Reusability of Worm Gear Sets {5207, 7552} Caterpillar

Motor Grader

120H (S/N: 1241-UP; CAF1-UP; 4MK1-UP; 5FM1-UP; 6NM1-UP; 6TM1-UP; 2AN1-UP; 6YN1-UP; 9YR1-UP; ALZ1-UP)

120K (S/N: SZN1-UP; JAP1-UP)

120K Series 2 (S/N: SZS1-UP)

120M (S/N: PJB1-UP; B9C1-UP; B9N1-UP; B9W1-UP; D9W1-UP)

120M Series 2 (S/N: M9C1-UP; M9H1-UP; R9N1-UP; R9W1-UP)

12H (S/N: 1251-UP; XZJ1-UP; CBK1-UP; 4XM1-UP; 5ZM1-UP; 8MN1-UP; 2LR1-UP; 2WR1-UP; 4ER1-UP; 2GS1-UP; AMZ1-UP)

12K (S/N: JJA1-UP; SZP1-UP)

12M (S/N: B921-UP; B9F1-UP; B9R1-UP)

12M Series 2 (S/N: F9B1-UP; F9M1-UP; R9P1-UP; R9S1-UP)

12M Series 3 (S/N: N9B1-UP; N9F1-UP; N9P1-UP; N9R1-UP)

135H (S/N: CBC1-UP; BDJ1-UP; 3YK1-UP; 7MM1-UP; 8WN1-UP; AMX1-UP)

140H (S/N: 1261-UP; CCA1-UP; XZH1-UP; 2ZK1-UP; APM1-UP; 5HM1-UP; 8JM1-UP; 8KM1-UP; 9TN1-UP; 9ZN1-UP; 3AS1-UP)

140K (S/N: JPA1-UP; SZL1-UP)

140K Series 2 (S/N: SZW1-UP)

140M (S/N: B9D1-UP; B9G1-UP; D9G1-UP; B9M1-UP)

140M Series 2 (S/N: M9D1-UP; R9G1-UP; M9J1-UP; R9M1-UP)

140M Series 3 (S/N: N9D1-UP; N9G1-UP; N9J1-UP; N9M1-UP)

143H (S/N: 1AL1-UP; APN1-UP)

14H (S/N: ASE1-UP; 7WJ1-UP)

14L (S/N: B941-UP)

14M (S/N: B9J1-UP; R9J1-UP)

14M Series 3 (S/N: E9S1-UP; N9S1-UP)

160H (S/N: ASD1-UP; 9EJ1-UP; XZK1-UP; 2FM1-UP; 3GM1-UP; 6WM1-UP; 9JM1-UP; CCP1-UP; 2HS1-UP)

160K (S/N: SZM1-UP; JBP1-UP)

160M (S/N: B9E1-UP; B9L1-UP; B9T1-UP; D9T1-UP)

160M Series 2 (S/N: M9E1-UP; M9K1-UP; R9L1-UP; R9T1-UP)

160M Series 3 (S/N: N9E1-UP; N9K1-UP; N9L1-UP; N9T1-UP)

163H (S/N: 5AK1-UP; ARL1-UP)

16G (S/N: 93U1-UP)

16H (S/N: 6ZJ1-UP; ATS1-UP)

16M (S/N: B9H1-UP; R9H1-UP)

16M Series 3 (S/N: E9Y1-UP; N9Y1-UP)

18M Series 3 (S/N: N9A1-UP; E9W1-UP)

24H (S/N: 7KK1-UP)

24M (S/N: B931-UP; B9K1-UP)

Introduction

© 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.

Summary

This guideline provides the procedures that are required to evaluate the reusability of worm gear sets for motor grader circle drives. This guideline allows Cat dealer personnel to determine the reusability of a worm gear set accurately. The information that is provided in this guideline can also be submitted to a customer to ensure that proper reusability guidelines are being followed. Part numbers that are affected by this guideline are shown in Table 2. Often, worm gears may be reused even if significant wear is evident. This guideline contains the latest standards that will help minimize owning and operating costs. Parts that meet the specifications in this guideline can be expected to give normal performance until the next scheduled overhaul. Do not install a part that should not be used again according to this guideline. Any condition that might have caused the original wear to occur should be corrected during the repair procedure.

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.

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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.

Service Letters and Technical Information Bulletins

Tooling and Equipment

Table 3 contains the items that are needed to complete the repair procedures in this guideline.

Prepare the Area for Inspection

Illustration 3	g00008666

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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.

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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 205 kPa (30 psi) for cleaning purposes.

Illustration 4	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

• Before you inspect a part, clean the part thoroughly to ensure that all components are free from rust, oil, burrs, and debris prior to inspection. A surface irregularity can hide the indication of an unacceptable defect.

• 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 component 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.

Considerations for the Reusability of Circle Worm Gear Sets

The circle worm is a machined steel casting with one thread. The worm is meshed with the brass (16-24 machines) or aluminum (12.14, 120-160 machines) worm gear in the circle drive to provide the torque increase and speed reduction needed to rotate the blade. During normal operation of the circle drive, worm and worm gear wear will occur. The worm is a hardened steel component. Therefore, most wear will be restricted to the worm gear, but pitting and scoring will also occur on the worm. Wear on both components is normal. Wear on the worm gear that is kept within the specifications suggested in this guideline will not have a detrimental effect on the operation of the machine. A significant amount of wear can occur before the worm gear set must be removed and replaced with a new worm and worm gear. Do not apply the criteria for reusability of a gear worm to any other gear. The application of the gear worm is different from a typical transmission, final drive, or any other type of gear.

To determine reusability of the worm gear set, the following must be considered:

The width of the individual teeth on the worm gear

Inspect the individual teeth on a worm gear. The teeth should not be worn to a knife edge. As wear occurs, the gear loses tooth thickness. The width of the remaining surface is defined as the face width.

A reusable gear worm may also exhibit various types of wear. The gear may be reused in most instances even with the following types of wear.

• Scoring or galling from abrasive wear may be present particularly if insufficient lubrication has been applied.

• Scratches and pits from abrasive wear may be present due to fine abrasive material in the film of the lube or insufficient lube.

Note: The life of the worm gear set depends lubrication. Adequate lubrication with the recommended oil type for the circle drive will greatly extend the life of the worm gear set and other circle drive components. Refer to the appropriate Operation and Maintenance Manual.

Illustration 5	g03652264
This gear shows the tooth worn to a knife edge and CANNOT BE REUSED. No part of the tooth face should be at a knife edge.

Illustration 6	g03652272
This gear has significant material remaining and should be reused.

Illustration 7	g03652280
This gear has a face width greater than 3.0 mm (0.12 inch), the variation between gears is between 3.0 mm (0.12 inch) and 6.0 mm (0.24 inch), and should be reused.

Illustration 8	g03652282
Dimension (A) shows the remaining face width. The critical dimension in determining the reusability of a gear worm is the width of the tooth face. Measure the remaining face width to determine the reusability of the worm gear.

Note: When wear occurs, individual gear teeth may exhibit various face widths. A difference in the remaining face width of 3 mm (0.12 inch) to 6.0 mm (0.24 inch) is acceptable. Gears with variation between the face widths of individual gear teeth that are more than 6.0 mm (0.24 inch) should not be reused.

Procedure for Inspection of the Circle Drive Gear Worm

1. All safety precautions must be followed before measuring the worm gear.

2. Clean the worm gear, removing any lubrication and debris prior to completing the measurement.

3. Use a vernier caliper to measure Dimension (A) for every tooth. Dimension (A) represents the remaining face width and must be equal to or greater than 3.0 mm (0.12 inch). If any tooth face has become a knife edge, the part cannot be reused.

Note: The remaining face width should be measured from the center of the gear face. Refer to Illustration 8.