- Off-Highway Truck/Tractor
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Introduction
Revision | Summary of Changes in SEBF8271 |
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16 | Updated tables with correct information by model, added correct footnotes |
15 | Updated the process for using plug gauge. |
14 | Republish due to errors. |
13 | Removed part number |
© 2018 Caterpillar All Rights Reserved. This guideline is for the use of Cat dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law.
Information contained in this document is considered Caterpillar: Confidential Yellow.
This Reuse and Salvage Guideline contains the necessary information to allow a dealer to establish a parts reusability program. Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.
For technical questions when using this document, work with your Dealer Technical Communicator (TC).
To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS Web) interface.
Canceled Part Numbers and Replaced Part Numbers
This document may include canceled part numbers and replaced part numbers. Use NPR on SIS for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.
Note: Illustrations in this guideline may appear different from some of the components. Although the illustrations are typical, the dimensions are actual.
Important Safety Information
Illustration 1 | g02139237 |
Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly. Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method, or operating technique that is not recommended by Caterpillar is used, ensure that it is safe for you and for other people to use. Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.
Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death. Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information. |
Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.
The hazards are identified by the safety alert symbol which is followed by a signal word such as danger, warning, or caution. The “WARNING” safety alert symbol is shown below.
Illustration 2 | g00008666 |
This safety alert symbol means:
Pay attention!
Become alert!
Your safety is involved.
The message that appears under the safety alert symbol explains the hazard.
Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.
Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.
The information, the specifications, and the illustrations that exist in this guideline are based on information which was available at the time of publication. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete, most current information before you start any job. Caterpillar dealers can supply the most current information.
Summary
This guideline will describe procedures which can be used for the inspection and salvage of tapered bores for the following components in the steering system:
- Steering Arm
- Center Arm
- Steering Box
Tapered bores that meet the specifications in this guideline can be expected to give normal performance in the same application until the next scheduled overhaul. Do not install a part that is not reusable. During reconditioning, correct any condition that might have caused the original failure.
Note: Do not weld on any of the components for the tapered steering bore. Refer to Reuse and Salvage Guideline, REHS2110, "Center Steering Arm Straight Bore Inspection and Salvage Procedure for Off-Highway Trucks".
This Reuse and Salvage Guideline will provide the procedure to measure the wear patterns on a bore by using a Plug Gauge. This Reuse and Salvage Guideline explains the proper process to use Bluing Paste. Refer to Table 4 through Table 12 for the Plug Gauge part numbers.
This document will use a typical steering arm and a typical steering box to illustrate these procedures.
This Reuse and Salvage Guideline will explain the lapping work and the oversize machining procedures for tapered bores. These processes will enable the customer to salvage the existing steering system by using either a new ball stud or an oversize ball stud. The required tools for lapping work are listed in Table 3.
This guideline contains the latest standards of engineering, which will help minimize owning and operating costs. A part can be expected to reach the next Planned Component Repair. A part that meets the specifications within this guideline and if the part is used in the same application. Use this guideline to determine whether a part should be reused. Do not install a part that is not reusable. During reconditioning, correct any condition that might have caused the original failure.
Illustration 3 | g01197906 |
A typical example of the steering system for a 793C is shown in this illustration. (1) Steering Arm (2) Steering Box (3) Center Arm (4) Tapered Bore (5) Ball Stud |
Service Letters and Technical Information Bulletins
NOTICE |
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The most recent Service Letters and Technical Information Bulletins that are related to this component shall be reviewed before beginning work. Often Service Letters and Technical Information Bulletins contain upgrades in repair procedures, parts, and safety information that pertain to the parts or components being repaired. |
References
References | |
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Media Number | Title |
REHS0541 | Procedure for the Inspection, Repair, and Component Replacement on the Frames of Certain Off-Highway Trucks/Tractors |
REHS2110 | Center Steering Arm Straight Bore Inspection and Salvage Procedure for Off-Highway Trucks |
REHS5059 | Field Procedure to Rework the Bores for the Steering Support |
SEBF8187 | Standardized Parts Marking Procedures |
SEPD0673 | Correction to Disassembly and Assembly , "Steering Cylinders |
SEPD0752 | Procedure to Inspect the Steering Ball Studs |
Tooling and Equipment
NOTICE |
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Failure to follow the recommended procedure or the specified tooling that is required for the procedure could result in damage to components. To avoid component damage, follow the recommended procedure using the recommended tools. |
Table 3 contains the items that are needed to complete the repair procedures in this guideline.
Tooling and Equipment | |
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Part Number | Description |
- | Thread Tap |
Threaded Shaft | |
Disc Pad Holder | |
Discs (Coarse) | |
Spanner Wrench As | |
- | Penetrant |
- | Developer |
Flapper Wheel (2" x 1" 120 grit) |
|
Wheel Adapter | |
2 1/2 inch Socket | |
- | 1 lb bottle of Lapping Compound |
Eye Loupe | |
12 oz bottle of Lapping Compound | |
Surface Texture Comparison Gauge | |
Metal Marking Pen | |
Die Grinder | |
Right Angle Die Grinder | |
- | Crack Detection Kit |
- | Bluing Paste |
UV Light Kit | |
- | 1 inch Square Drive Ratchet |
Part numbers for the Required Plug Gauge, Lapping Tool, and Ball Stud | ||||
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Part Number | Part Name | Plug Gauge Gp | Lapping Tool | Ball Stud |
Center Arm | ||||
Steering Arm | ||||
Box / Bracket Assembly |
Part numbers for the Required Plug Gauge, Lapping Tool, and Ball Stud | ||||
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Part Number | Part Name | Plug Gauge Gp | Lapping Tool | Ball Stud |
Center Arm | ||||
Steering Arm | ||||
Box / Bracket Assembly |
Part numbers for the Required Plug Gauge, Lapping Tool, and Ball Stud | ||||
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Part Number | Part Name | Plug Gauge Gp | Lapping Tool | Ball Stud |
Center Arm | ||||
Steering Arm | ||||
Bracket Assembly |
Part numbers for the Required Plug Gauge, Lapping Tool, Tapered Reamer, and Ball Stud | |||||||
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Part Number | Part Name | Plug Gauge Gp | Lapping Tool | Ball Stud | Roughing Reamer | Finishing Reamer | Oversize Ball Stud |
Center Arm | |||||||
Steering Arm | |||||||
Bracket Assembly |
Part numbers for the Required Plug Gauge, Lapping Tool, Tapered Reamer, and Ball Stud | |||||||
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Part Number | Part Name | Plug Gauge Gp | Lapping Tool | Ball Stud | Roughing Reamer | Finishing Reamer | Oversize Ball Stud |
Center Arm | |||||||
Steering Arm | |||||||
Bracket Assembly |
Part numbers for the Required Plug Gauge, Lapping Tool, Tapered Reamer, and Ball Stud | |||||||
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Part Number | Part Name | Plug Gauge Gp | Lapping Tool | Ball Stud | Roughing Reamer | Finishing Reamer | Oversize Ball Stud |
Center Arm | |||||||
Steering Arm | |||||||
Bracket Assembly |
Part numbers for the Required Plug Gauge, Lapping Tool, Tapered Reamer, and Ball Stud | |||||||
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Part Number | Part Name | Plug Gauge Gp | Lapping Tool | Ball Stud | Roughing Reamer | Finishing Reamer | Oversize Ball Stud |
Steering Arm | N/A | ||||||
Support Assembly |
Part numbers for the Required Plug Gauge, Lapping Tool, Tapered Reamer, and Ball Stud | |||||||
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Part Number | Part Name | Plug Gauge Gp | Lapping Tool | Ball Stud | Roughing Reamer | Finishing Reamer | Oversize Ball Stud |
Center Arm | N/A | ||||||
Steering Arm | |||||||
Support Assembly |
Part numbers for the Required Plug Gauge, Lapping Tool, Tapered Reamer, and Ball Stud | |||||||
---|---|---|---|---|---|---|---|
Part Number | Part Name | Plug Gauge Gp | Lapping Tool | Ball Stud | Roughing Reamer | Finishing Reamer | Oversize Ball Stud |
Center Arm | N/A | ||||||
Steering Arm | |||||||
Support Assembly |
Standardized Parts Marking Procedure
Reference: SEBF8187Reuse and Salvage Guidelines, "Standardized Parts Marking Procedures".
The code is a Cat standard and is used to record the history of a component. The code will identify the number of rebuilds and hours at the time of each rebuild. This information is important and should be considered for any decision to reuse a component.
Ensure that the mark is not covered by a mating part. Use a metal marking pen to mark the code onto the component.
NOTICE |
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Do not use numbering stamp punches to mark internal components. The impact from striking the stamp will cause an abnormal stress riser. The added stress riser may cause premature part failure. |
Illustration 4 | g06124077 |
DO NOT use numbering stamp punches to mark internal components. |
The procedure for marking components is a Cat standard. This code is helpful when the machine is sold into a different territory after the first rebuild. During an overhaul, the previous code of a part should never be removed.
Illustration 5 | g03683915 |
Illustration 5 shows code (1-15). The first number (1) indicates that the component had been repaired once. The second number (15) indicates that there were 15,000 hours on the component at the time of repair. |
Illustration 6 | g03683920 |
Illustration 6 shows code (1-12) and code (2-10). Code (2-10) represents the information from the second repair. The first number (2) indicates that the component had been repaired twice. The second number (10) indicates that there were 10,000 hours on the component at the time of repair. |
This coding can be used by all dealers and will help with identification at time of repair. Identification can be especially helpful if units that have been repaired are sold into different territories. As new overhauls are completed, the previous markings should be left on the part. To obtain the total number of hours for the component in Illustration, 6 you must add first and second repaired hours. In this example the component has a total of 22,000 hours.
Cleaning Recommendations
Personal injury can result when using cleaner solvents. To help prevent personal injury, follow the instructions and warnings on the cleaner solvent container before using. |
Personal injury can result from air pressure. Personal injury can result without following proper procedure. When using pressure air, wear a protective face shield and protective clothing. Maximum air pressure at the nozzle must be less than |
Illustration 7 | g03721203 |
Typical burr removal tooling. (A) Right Angle Die Grinder (B) Die Grinder (C) ( D) ( E) Conditioning Discs, Disc Pad Holder, and Threaded Shaft (F) ( G) Flapper Wheels |
- Clean all surfaces for inspection before you inspect the part. Make sure that you remove all debris, paint, and oil.
- When you move parts that require cleaning, always use a proper lifting device. This device must protect the part from damage. For the safety of the operator, all lifting devices must be inspected before use.
- During cleaning, do not damage machined surfaces.
- Use pressurized air to dry parts.
- If the tapered bore cannot be inspected immediately after cleaning, put hydraulic oil on all machined surfaces to prevent rust or corrosion. Carefully store the parts in a clean container.
Inspection of the Tapered Bore
Unless you have an established inspection program for the particular application, inspect the ball studs after every 1000 hours of operation. Refer to the appropriate Operation and Maintenance Manual. A ball stud may be checked for cracks by using several methods one method is Ultrasonic Testing. Ultrasonic Testing can be completed without removing the ball stud. Refer to Service Magazine, SEPD0752, "Procedure to Inspect the Steering Ball Studs"
During every scheduled replacement for the ball stud, inspect the tapered steering bore. Also, when you find cracks in a ball stud, inspect the tapered steering bore. Refer to Illustration 8 and Table 13 through Table 15 for the dimensions that need to be inspected on the tapered bores.
Illustration 8 | g03646975 |
(A) Depth of ball stud inside tapered bore
(B) Overall length of bore (C) Upper diameter for ball stud (D) Measurement location for gauge diameter (E) Gauge diameter (F) Taper (G) Surface finish (H) Straight bore diameter |
- Remove the ball stud from the tapered steering bore. For the removal procedure of ball studs, refer to Disassembly and Assembly Manual, SEPD0673, "Correction to Disassembly and Assembly, "Steering Cylinder" and Correction to Disassembly and Assembly, "Tie Rod (Steering)".
Show/hide table
Illustration 9 g03646979 Remove corrosion from the tapered bore prior to inspection. - To inspect the bore properly, the surface must be free of paint or corrosion. If the surface finish is not free of paint or corrosion, use a 4C-8515 Flapper Wheel and a 4C-8521 Wheel Adapter or use the Lapping Procedure to clean the bore. Refer to the"Lapping Procedure for a Tapered Bore".
Process for using the Plug Gauge
- Apply Bluing Paste to the taper surface of the Plug Gauge. Make sure that the Bluing Paste is evenly distributed onto the taper surface with minimum thickness. For models 768-777 steering box taper bores, skip this step and proceed to Step 2.
- Gently insert the Plug Gauge into the tapered bore by using hand pressure. Turn the Plug Gauge by approximately 180 degrees.
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Illustration 12 g03646990 Show/hide tableIllustration 13 g03646995 (A) Checking steps. - Although the Plug Gauge is located inside the tapered bore, the steps on the small end of the tapered Plug Gauge can be used to verify that the length of the tapered bore is correct. This will allow the ball stud to seat properly when the ball stud is torqued. See Illustration 13.
On some Plug Gauges the step is machined into the Plug Gauge on others there are four color coded steps in the end of the Plug Gauge. The green marked steps are used to check a tapered bore that is new. Use a standard ball stud in this type of tapered bore. The red marked steps are used to check a tapered bore that has been machined oversize. Use an oversized ball stud in this type of tapered bore.
The face of the new standard bore or oversize bore that is being inspected should fall within the tolerance that is machined into the end of the Plug Gauge. This tolerance is indicated by a step between either two green marks or two red marks. If the steps on the gauge extend beyond the face of the bore, the tapered bore is out of tolerance. The proper torque on the ball stud cannot be obtained if the bore is outside of the proper tolerance.
You may ream the bore to an oversized dimension if the bore is outside of the tolerance range for a standard bore. You may then use an oversized ball. If the oversized bore is out of tolerance, the part cannot be used and the part must be scrapped.
Note: Models 768-777 do not have the option for an oversized ball stud. For these models if the standard bore is out of tolerance, the part cannot be used and the part must be scrapped.
Show/hide tableIllustration 14 g01198001 This is an unacceptable wear pattern. - Once you have completed the steps above, remove the Plug Gauge straight. Visually inspect the contact surface on the bore.
Note: For models 768-777, the steering cylinder tapered bores located in the steering box are exempt from Step 4.
The Bluing Paste must indicate that at least 75% of the surface of the gauge contacted the bore. The Bluing Paste must also indicate solid contact for the full length of the 75% contact area. The bore in Illustration 14 does not meet the 75% rule.
Illustration 10 | g03646984 |
This is a |
Illustration 11 | g03646948 |
Note : Bluing is not required for models 768-777 steering box tapered bores. |
Note: Do not use any other Bluing Paste. This paste was chosen for this application. Do not add oil to the Bluing Paste.
Illustration 15 | g01198147 |
Unacceptable wear patterns are shown on the tapered bore. Some of the bores in this illustration meet the “75% rule”. However, these bores fail to meet the “full length of the taper at some point rule”. DO NOT USE AGAIN You may recondition the bore. Refer to the"Lapping Procedure for a Tapered Bore". |
Illustration 16 | g01198152 |
Acceptable wear patterns on a tapered bore. |
Illustration 17 | g01198155 |
Acceptable wear patterns on a tapered bore. |
Note: The examples in Illustrations 14 through 17 represent the results that may be obtained through the process of bluing. To be used again, the contact area must be visible across the full length of the taper. The “full-length” contact area does not include the bottom section that is not tapered. Therefore, the bottom section should not show any signs of contact.
Illustration 18 | g03647045 |
Typical example of a tapered bore. |
Specifications for the Tapered Bore of the Steering Arm | |||||||||
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Truck Model | Part Number | A Min | A Max | B | D | E | F | G | H |
769, 771 | Min |
Max |
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1:8 | F | |
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770, 772 | |
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773, 775 | |
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777 | |||||||||
785 | Min |
Max |
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789 | Min |
Max |
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793 | |||||||||
797A | (1) | |
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795 | Min Max |
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797B, 797F |
(1) | NOTE: Upgrade the steering linkage on a 797 to the 797B steering linkage. Do not rework the steering linkage for a 797. |
Specifications for the Tapered Bores on the Center Arm | |||||||||
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Truck Model | Part Number | A Min | A Max | B | D | E | F | G | H |
769, 771 | Min |
Max |
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1:8 | F | |
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773, 775 | |
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777 | |||||||||
785 | Min |
Max |
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789 | Min |
Max |
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793 | |||||||||
797A | (1) | |
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797B, 797F | Min |
Max |
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(1) | NOTE: Upgrade the steering linkage on a 797 to the 797B steering linkage. Do not rework the steering linkage for a 797. |
Specifications for the Tapered Bores on the Steering Box | |||||||||
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Truck Model | Part Number | A Min | A Max | B (1) | D | E | F | G | H |
769, 771 | Min |
Max |
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1:8 | F | |
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773, 775 | |
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777 | |||||||||
785 | Min 6.10 mm |
Max 9.10 mm |
N/A | |
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789 | Min |
Max |
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793 | |||||||||
795 | N/A | N/A | (2) | |
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797A | (3) | ||||||||
797B,797F | N/A | N/A |
(1) | NOTE: Dimension (B) is not critical for determining the reusability of the steering box. |
(2) | NOTE: The 795F, 797, 797B, 797F steering boxes do not utilize ball studs. |
(3) | NOTE: Upgrade the steering linkage on a 797 to the 797B steering linkage. Do not rework the steering linkage for a 797. |
Lapping Procedure for a Tapered Bore
If the tapered bore did not meet the specifications that were outlined in the "Process for using the Plug Gauge" section of this guideline, use the following instructions to recondition the bore. Lapping is the recommended procedure for the repair of a tapered bore.
After the Lapping Procedure has been completed, the tapered bore must be inspected again with the Plug Gauge Procedure. If the bore fails to meet the inspection specifications after lapping, replace the component or you should machine the bore to an oversize dimension.
Procedure
The Lapping Tool should be used to lap the tapered bores. Failure to use the appropriate tooling may result in an unsatisfactory tapered bore and premature failure of the ball stud or tapered bore.
Illustration 19 | g01198158 |
Apply Lapping Compound to the Lapping Tool. Apply Lapping Compound to the area (A) that is shown in Illustration 19. |
- Apply Lapping Compound on the Lapping Tool. The compound should be applied so that the thickness is approximately
1.5 mm (0.06 inch) thick. - Insert the tool into the tapered bore and lightly tap the tool with a rubber mallet. Mark the location of the tool and the component so the number of rotations can be counted.
Show/hide table
Illustration 20 g01198162 Lapping the tapered bore. - Use the Spanner Socket to turn the Lapping Tool 12 times in the clockwise direction.
Note: Throughout the Lapping Procedure, apply a downward force. Be sure to keep the Lapping Tool straight in the tapered bore.
- Use the Spanner Socket to turn the tool 12 times in the counterclockwise rotation.
- Remove the Lapping Tool from the bore.
Note: Be sure to remove the Lapping Tool straight out of the bore.
- Thoroughly clean the bore to remove all Lapping Compound.
- Inspect the surface texture of the tapered bore. An F surface finish should be maintained after the lapping procedure. Use the 9A-1593 Surface Texture Comparison Gauge.
- Inspect the contact pattern on the tapered bore. Refer to the "Inspection of the Tapered Bore" section of this Reuse and Salvage Guideline.
- If the bore has passed inspection, clean the tapered bore. Install a new ball stud and tighten to the appropriate torque. Refer to the appropriate manual for Disassembly and Assembly.
Lapping Tool Usage
The Lapping Tool is hardened to extend the service life. Repeated usage will cause the tool to wear. As the tool is used, the surface finish will degrade. After repeated usage, the Lapping Compound will score the surface.
Due to the nature of lapping work, a Lapping Tool has a finite life. The Lapping Tool should be able to lap approximately eight bores before the tool should be replaced.
If the Lapping Tool does not achieve the specified finish and the specified contact pattern, the Lapping Tool should be discarded and a new tool should be used.
Note: The Lapping Tool may experience uneven wear if the Lapping Tool is used on various sized tapered bores. If the wear is uneven, the Lapping Tool will not be effective.
Avoid using the Lapping Tool on different-sized bores. Designate an individual tool for each truck model or bore size.
Oversize Machining Procedure
NOTICE |
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When completing the oversize reaming procedure, it is critical that the proper surface finish and minimum contact area be achieved. Use the Hard Gage for inspection purposes. If the minimum specifications cannot be achieved following the reaming procedure, the component should be replaced. |
Use the following steps to verify that the assembled ball stud will be properly seated in the tapered bore after the ball stud is torqued:
- Use a suitable lifting device to install the steering arm or the center arm onto a suitable station for machining.
If the steering box is being reamed, refer to the following note:
Note: To machine the steering box in chassis, the engine must be removed. When possible, the repair of the steering box should be scheduled to coincide with normal engine repair and maintenance.
If proper tooling for the machine is not available to rework the steering box in chassis, refer to Special Instruction, REHS0541, "Procedure for the Inspection, Repair, and Component Replacement on the Frames of Certain Off-Highway Trucks/Tractors" for information concerning the 785 to 793. This procedure can be performed while the engine is installed.
- Calculate the initial cut depth of the Roughing Reamer. If the Roughing Reamer is new, refer to Table 16. If the Roughing Reamer has been sharpened, calculate the depth of the initial cut by using Step 2.a through Step 2.c.
Show/hide table
Table 16 Initial Cut Depth of the Tapered Reamer (1) Model Roughing Reamer 784, 785 132.62 mm (5.221 inch) 789 793 797 143.68 mm (5.657 inch) (2)Show/hide table(1) See Table 7 through Table 12 for the part numbers for the correct reamer. (2) The 797B reamer is designed as a Roughing Reamer and a Finishing Reamer. - Measure the large end of the reamer (W).
- Calculate dimension (J) on the Roughing Reamer through the following equation:
L − (W − E) × 8 = J
Show/hide tableTable 17 Roughing Reamer Dimensions Model L E 784, 785 142.20 mm
(5.598 inch) 76.59 mm
(3.015 inch) 789 75.04 mm
(2.954 inch) 793 797 171.00 mm
(6.732 inch) 101.44 mm
(3.994 inch) Show/hide tableIllustration 22 g06284383 (A) Depth of ball stud inside tapered bore
(D) Measurement location for gauge diameter
(E) Gauge diameter
(H) Straight bore diameter
(K) Measurement location for gauge diameter
(X) Measurement thickness of steering component - Calculate the initial cut depth by using the following equation:
K + J −
2.00 mm (0.079 inch) = M (Initial Cut Depth)See Illustration 23.
Note:
2.00 mm (0.079 inch) is subtracted from the calculated cut depth to leave some material for the operation for finishing.Show/hide tableTable 18 Oversized Tapered Bore Dimensions Truck Model A Min A Max D E H K 785 Min 6.10 mm
(0..240 inch) Max 9.10 mm
(0.358 inch) 55.20 ± 1.0 mm
(2.173 ± 0.039 inch) 76.59 mm
(3.015 inch) 69.46 ± 0.25 mm
(2.735 ± 0.01 inch) K = X - D 789 Min 5.68 mm
(0.224 inch) Max 8.68 mm
(0.343 inch) 65.00 ± 1.0 mm
(2.559 ± 0.039 inch) 75.04 mm
(2.954 inch) 67.00 ± 0.25 mm
(2.638 ± 0.01 inch) 793 797A (1) 795 Min 11.97 mm
(0.471 inch) Max 14.97 mm
(0.589 inch) 65.00 ± 1.0 mm
(2.559 ± 0.039 inch) 101.44 mm
(3.994 inch) 93.24 ± 0.25 mm
(3.671 ± 0.01 inch) K = X - D 797B, 797F Show/hide table(1) NOTE: Upgrade the steering linkage on a 797 to the 797B steering linkage. Do not rework the steering linkage for a 797.
Show/hide tableIllustration 21 g03647214 (W) Large width of reamer
(L) Full length of reamer
(E) Gauge diameter
(J) Measurement location for gauge diameter - Install the Roughing Reamer in the drill. Use the 202-8960 Roughing Reamer for the models 784 through 793. Use the 258-5684 Reamer for the 797B. See Table 7 through Table 12.
Show/hide table
Illustration 23 g03647221 (A) Shim
(M) Initial cut depth - Locate the Roughing Reamer to the top face of the component that is being reamed. Use the 8H-8581 Feeler Gauge and the
0.005 mm (0.0002 inch) to the0.008 mm (0.0003 inch) shim. - Locate the center of the tapered bore. Use the dimensions in Table 22 through Table 2and Illustration 25 through Illustration 29 in the "Machining Dimensions" section of this Reuse and Salvage Guideline.
Note: Step 4 and Step 5 are critical because the reamer must be perpendicular to the surface of the component.
- Complete the operation for rough reaming.
- Remove the Roughing Reamer.
- Calculate the initial cut depth of the Finishing Reamer. If the reamer is new, refer to Table 19. If the reamer has been sharpened, calculate the depth of the initial cut by using Step 8.a through Step 8.c.
Show/hide table
Table 19 Initial Cut Depth of the Tapered Reamer (1) Model Finishing Reamer 784, 785 131.62 mm (5.182 inch) 789 793 797 Show/hide table(1) See Table 7 through Table 12 for the part numbers for the correct reamer. - Measure the large end of the reamer (W).
- Calculate dimension (J) on the reamer through the following equation:
L − (W − E) × 8 = J
Show/hide tableTable 20 Finishing Reamer Dimensions Model L E 784, 785 139.20 mm
(5.480 inch) 76.59 mm
(3.015 inch) 789 75.04 mm
(2.954 inch) 793 797 171.00 mm
(6.732 inch) 101.44 mm
(3.994 inch) - Calculate the initial cut depth by using the following equation:
K + J = M (Initial Cut Depth)
See Illustration 23.
Note: This is the depth that is needed to achieve the proper gauge diameter and this measurement should be used for the Finishing Reamer. Dimension (K) is listed in Table 18.
- Install the Finishing Reamer in the drill. Use the 202-8961 Finishing Reamer for models 784 through 793. Use the 258-5684 Reamer for the 797B.
- Locate the Finishing Reamer to the top face of the component that is being reamed. Use the 8H-8581 Feeler Gauge and the
0.005 mm (0.0002 inch) to the0.008 mm (0.0003 inch) shim. - Locate the center of the tapered bore. Use the dimensions in Table 22 through Table 2and Illustration 25 through Illustration 29 in the "Machining Dimensions" section of this Reuse and Salvage Guideline.
Note: Step 10 and Step 11 are critical because the reamer must be perpendicular to the surface of the component.
- Complete the operation for finishing.
- Remove the Finishing Reamer.
- Check the surface finish of the tapered bore. Use the 9A-1593 Comparison Gauge (SURFACE TEXTURE). The surface must be an F finish.
Note: Obtaining an F finish is critical. If the proper surface finish cannot be obtained in any of the tapered bores, the respective component should be replaced.
- Check the tapered bore by using the procedure that is in the "Process for using the Plug Gauge" section of this guideline.
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Illustration 24 g01233861 - If the bore has passed inspection, clean the tapered bore. Install a new oversized ball stud and tighten the ball stud to the appropriate torque. Refer to the appropriate Disassembly and Assembly manual for the installation procedures. Refer to Table 21 for the part numbers and the dimensions for oversized ball studs.
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Table 21 Summary of Ball Studs Part Number (Original Equipment) Part Number (Oversize Ball Stud) Original Diameter (Z) Diameter (Z) (Oversize) 9M-5901 ,6D-1726 ,6D-9908 ,193-4624 N/A 44.45 ± 0.25 mm
(1.750 ± 0.01 inch) N/A 273-3160 N/A 44.76 ± 0.25 mm
(1.762 ± 0.01 inch) N/A 273-0120 ,316-6375 N/A 53.57 ± 0.08 mm
(2.109 ± 0.003 inch) N/A 7D-1292 ,221-5305 N/A 53.34 ± 0.08 mm
(2.100 ± 0.003 inch) N/A 5T-8597 ,8X-9619 217-8419 82.55 ± 0.25 mm
(3.250 ± 0.01 inch) 83.34 ± 0.25 mm
(3.281 ± 0.01 inch) 5T-6502 ,8X-9620 123-6672 156-8136 192-5702 ,438-1135 N/A 109.73 ± 0.25 mm
(4.320 ± 0.01 inch) N/A Show/hide tableNOTICE If Dimension (A) is less than the minimum specification, the proper torque on the oversized ball stud nut cannot be obtained.
If any of the specifications are not met, the tapered bore cannot be salvaged and the component must be replaced.
- If the proper finish or the contact area is not within the specifications, increase the depth of the reamer until the specifications are met. Dimension (A) must not be less than the minimum specification in Table 18.
- If all the measurements and contact areas are acceptable, ream the next tapered bore by following Steps 1 through Step 17.
Machining Dimensions
Illustration 25 | g03646202 |
Typical example of steering arm. |
Illustration 26 | g03646261 |
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(1) | Refer to Illustration 26 |
Illustration 27 | g03646440 |
A typical example of center arm. |
Dimensions for Machining Center Arms | ||||||
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(1) | In two places. |
Illustration 28 | g03646512 |
Typical example of 768B through 785 and 797 steering boxes. |
Illustration 29 | g03646521 |
Typical example of 789 through 793 steering boxes. |
Dimensions for Steering Boxes | ||||||
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Part Number | X | Y | Z | AA | BB | CC |
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Crack Detection Methods
NOTICE |
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Regardless of which crack detection method is used, it is important that the instructions furnished with the detection equipment are followed closely when checking any component. Failure to do so may cause inaccurate results or may cause injury to the operator and/or surroundings. |
There are five major crack detection methods or Non-Destructive Testing (NDT) listed in this section: Visual Surface Inspection (VT), Liquid Penetrant Testing (PT), Dry / Wet Magnetic Particle Testing (MPT), Ultrasonic Testing (UT).
Crack detection methods or NDT is methods for testing components for cracks without damaging the component. VT, PT, Dry/ Wet MPT, and UT are methods recommended. There may be more than one acceptable crack detection method for the testing of a given part, although PT is the most versatile. For example, the PT method can be used when testing smooth machined components such as shafts, gear teeth, and splines, but using the Wet MPT is more accurate. Refer to Table 25 for advantages and disadvantages and Table 26 for standards and requirements for these NDT methods.
Crack Detection Methods Advantages vs. Disadvantages | ||
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Detection Method | Advantages | Disadvantages |
Visual Surface Inspection (VT) | - Least Expensive
- Detects most damaging defects. - Immediate Results - Minimum part preparation |
- Limited to surface-only defects.
- Requires inspectors to have broad knowledge of welding and fabrication in addition to Non-Destructive Testing (NDT). |
Liquid Penetrant Testing (PT) | - Inexpensive
- Minimal Training - Portable - Works on nonmagnetic material. |
- Least Sensitive
- Detects surface cracks only. - Rough or porous surfaces interfere with test |
Dry Magnetic Particle (MPT) | - Portable
- Fast/Immediate Results - Detects surface and subsurface discontinuities |
- Works on magnetic material only.
- Less sensitive than Wet Magnetic Particle Testing (MPT). |
Wet Magnetic Particle (MPT) | - More sensitive than Liquid Penetrant Testing (PT).
- Detects subsurface as much as |
- Requires power for light.
- Works on magnetic material only. - Liquid composition and agitation must be monitored. |
Ultrasonic Testing (UT) | - Most Sensitive
- Detects deep material defects. - Immediate Results - Wide range of materials and thickness can be inspected |
- Most Expensive
- Requires operator training and certification. - Surface must be accessible to probe |
Applicable Crack Detection Standards | |||
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Detection Method | Standard | Acceptance
Criteria |
Minimum
Required Personnel Qualifications |
Visual Surface Inspection (VT) | EN-ISO 5817
AWS D1.1 |
EN-ISO 5817 - Level B
AWS D1.1 - Table 6.1 |
EN-ISO 9712
ANSI-ASNT SNT-TC-1A |
Liquid Penetrant Testing (PT) | EN-ISO 3452
ASTM E165 |
EN-ISO 23277
AWS - D1.1 |
EN-ISO 9712
ANSI-ASNT SNT-TC-1A |
Magnetic Particle Testing (MPT) | EN-ISO 17638
ASTM E709 |
EN-ISO 23278 - Level 1
AWS D1.1 - Table 6.1 |
EN-ISO 9712
ANSI-ASNT SNT-TC-1A |
Ultrasonic Testing (UT) | EN-ISO 17640 - Level B
AWS D1.1 |
EN-ISO 11666 Technique 2 - Level 2
AWS D1.1 - Class A - Table 6.3 |
EN-ISO 9712
ANSI-ASNT SNT-TC-1A |
Visual Surface Inspection (VT)
Illustration 30 | g06085008 |
Example of Visual Surface Inspection (VT) Tooling (A) Flashlight (or adequate light source) (B) Magnifying Glass (C) Tape Measure (or other measuring device) (D) Inspection Mirror (E) Weld Size Inspection Gauges |
Refer to Tooling and Equipment Table 3 for part numbers.
Components and welds that are to be tested using PT, MPT, or UT shall first be subject to a Visual Surface Inspection (VT). VT is often the most cost-effective inspection method and requires little equipment as seen in Illustration 30. Personnel performing VT shall either be trained to a company standard or have sufficient experience and knowledge regarding the components being inspected. Personnel performing VT shall take routine eye exams.
Liquid Penetrant Testing (PT)
Personal injury can result from improper handling of chemicals. Make sure you use all the necessary protective equipment required to do the job. Make sure that you read and understand all directions and hazards described on the labels and material safety data sheet of any chemical that is used. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of chemicals. |
Materials and Equipment Required
Refer to Tooling and Equipment Table 3 for part numbers.
- Cleaner: Removes dirt before dye application and dissolves the penetrant making possible to wipe the surface clean.
- Penetrating Oil: This solution is highly visible, and will seep into openings at the surface of a part with capillary action.
- Developer: Provides a blotting action, bringing the penetrant out of the discontinuities and providing a contrasting background to increase the visibility of the penetrating oil indications.
- Wire Brush: Removes dirt and paint.
- Cloth or Wipes: Use with cleaner and for other miscellaneous uses.
Procedure
- Preclean the area to be tested. Spray on cleaner/ remover to loosen any scale, dirt, or any oil. Wipe the area to be tested with a solvent dampened cloth to remove remaining dirt and allow the area to dry. Remove paint where there are visible cracks using paint remover or a wire brush.
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Illustration 32 g06103803 Typical example of applying penetrating oil to areas to be tested. - Apply penetrant by spraying to the entire area to be tested. Allow 10 to 15 minutes for penetrant to soak. After the penetrating oil has been allowed to soak, remove the excess penetrating oil with clean, dry wipe.
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Illustration 33 g06103816 Typical example of removing penetrating oil with a cloth. - The last traces of penetrating oil should be removed with the cleaner solvent dampened cloth or wipe. Allow the area to dry thoroughly.
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Illustration 34 g06103820 Typical example of applying the developer. - Before using developer, ensure that the developer is mixed thoroughly by shaking the container. Hold the container approximately
203 - 305 mm (8.0 - 12.0 inch) away from the testing area. Apply an even, thin layer of developer over the testing area. A few thin layers are a better application method than one thick layer.Show/hide tableIllustration 35 g06084042 Typical example of cracks found during Liquid Penetrant Testing (PT). - Allow the developer to dry completely for 10–15 minutes before inspecting for cracks. Defects will show as red lines in white developer background, refer to Illustration 35. Clean the area of application of the developer with solvent cleaner.
Illustration 31 | g06103795 |
Typical example of pre-cleaning the testing area. |
Dry Magnetic Particle Testing (MPT)
Materials and Equipment Required
Refer to Tooling and Equipment Table 3 for part numbers.
Illustration 36 | g06085930 |
(A) Indications shown by Dry Magnetic Particle Testing (MPT).
(B) Electromagnetic Yoke (C) Dry Powder Bulb |
- Dry magnetic powder shall be of high permeability and low retentively and of suitable sizes and shapes to produce magnetic particle indications. The powder shall be of a color that will provide adequate contrast with the background of the surface being inspected.
- Dry magnetic particles shall be stored in suitable containers to resist contamination such as moisture, grease, oil, non-magnetic particles such as sand, and excessive heat. Contaminants will manifest in the form of particle color change and particle agglomeration. The degree of contamination will determine further use of the powder.
- Dry magnetic powder shall be tested in accordance with ASTM E709 Section 18 (Evaluation of System Performance/Sensitivity) when not performing.
- Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least
4.5 kg (10 lbs) . - Check dry powder blower routinely to ensure that the spray is a light, uniform, dust-like coating of the dry magnetic particles. Blower should also have sufficient force to remove excess particles without disturbing those particles that are evidence of indications.
- All equipment shall be inspected at a minimum of once a year or when accuracy is questionable.
Procedure
- Ensure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and other contaminants.
- Apply the magnetic field using the yoke against the faces and inside diameter of each bore.
- Simultaneously apply the dry powder using the dry powder blower.
- Remove excess powder by lightly blowing away the dry particles.
- Continue around the entire circumference of each bore. Position the yoke twice in each area at 1.57 rad (90°) to ensure that multiple directions of the magnetic field are created.
- Observe particles and note if any clusters of particles appear revealing an indication.
- Record the size and shape of any discontinuities or indications found.
Wet Magnetic Particle Testing (MPT)
Materials and Equipment
Refer to Tooling and Equipment Table 3 for part numbers.
Illustration 37 | g06085937 |
(A) Indications shown by Wet Magnetic Particle Testing (MPT).
(B) Electromagnetic Yoke (D) Ultraviolet Lamp |
Illustration 38 | g06003178 |
Pear Shaped Centrifuge Tube |
- Wet magnetic particles are fluorescent and are suspended in a vehicle in a given concentration that will allow application to the test surface by spraying.
- Concentration:
- The concentration of the suspended magnetic particles shall be as specified by the manufacturer and be checked by settling volume measurements.
- Concentrations are determined by measuring the settling volume by using an ASTM pear shaped centrifuge tube with a
1 mL (0.034 oz) stem with0.05 mL (0.0017 oz) divisions, refer to Illustration 38. Before sampling, the suspension shall be thoroughly mixed to assure suspension of all particles, which could have settled. A100 mL (3.40 oz) sample of the suspension shall be taken and allowed to settle for 30 minutes. The settling volume should be between0.1 mL (0.0034 oz) and0.25 mL (0.0085 oz) in a100 mL (3.40 oz) sample. - Wet magnetic particles may be suspended in a low viscosity oil or conditioned water.
- The oil shall have the following characteristics:
- Low viscosity not to exceed
5 mm2/s (5 cSt) at any temperature at which the vehicle is to be used. - Low inherent fluorescence and be non-reactive.
- Low viscosity not to exceed
- The conditioning agents used in the conditioned water shall have the following characteristics:
- Impart good wetting characteristics and good dispersion.
- Minimize foaming and be non-corrosive.
- Low viscosity shall not exceed a maximum viscosity of
5 mm2/s (5 cSt) at38° C (100° F) . - Non-fluorescent, non-reactive, and odorless.
- Alkalinity shall not exceed a pH of 10.5.
- Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least
4.5 kg (10 lbs) .
Procedure
- Ensure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and any other contaminants.
- Apply the magnetic field using the yoke against the surface in the area to be inspected.
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Illustration 39 g03536210 - For case hardened and ground surfaces:
- Due to the sensitivity required to locate the grinding cracks, inspection of case hardened and ground surfaces require that the yoke is applied so that the magnetic field is 1.57 rad (90°) to the expected direction of the indications. Also, due to the increased sensitivity resulting when the yoke is energized, the yoke is not moved until the evaluation is completed in the first direction. An AC yoke shall be used. See Illustration 39 for an example of yoke placement.
- Visually inspect for indications of discontinuities using the proper illumination.
- Record the size and shape of any discontinuities found.