Usage:
April 12, 2004
U-110
A-73
D-88
O-90
| After failure only |
PRODUCT SUPPORT PROGRAM FOR REPAIRING CRACKS IN THE HYDRAULIC OIL TANK OF CERTAIN 735, 740 EJECTOR, AND 740 ARTICULATED TRUCKS |
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| 5056 |
PS50776
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NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
TERMINATION DATE
April 30, 2007PROBLEM
In certain conditions, the hoist and brake systems hydraulic tank may crack on certain 735, 740 Ejector, and 740 Articulated Trucks.AFFECTED PRODUCT
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| 740 EJ |
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| 735 |
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| 740 EJ |
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PARTS NEEDED
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ACTION REQUIRED
Refer to RENR5140 and SEPD0025. See the attached rework procedure.
***** Group 2 *****
Refer to RENR5140 and SEPD0025. See the attached rework procedure.
SERVICE CLAIM ALLOWANCES
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PARTS DISPOSITION
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.Attach. (1-Group 1 Rework Procedure)
(2-Group 2 Rework Procedure)
GROUP 1 REWORK PROCEDURE
Oil Tank on 735, 740 and 740 Ejector Articulated Trucks
Problem Description - Group 1 Machines
Cracks may develop on the front, left and right-hand side plates of the hoist and brake systems hydraulic oil tank on certain 735, 740 and 740 Ejector Articulated Trucks.
On the front plate, vertical cracks may develop where an internal baffle plate is welded to the tank's front plate, this is in an area approximately 330 mm from the left-hand side of the tank - see the illustration below.
Cracks may also develop in the front plate when tack welds have been used to temporarily locate the battery support plate during tank manufacture.
On the left-hand side plate, vertical cracks may develop where the hydraulic tank rear plate is attached to the side plate - see the illustration below.
On the right-hand side plate, vertical cracks may develop where the hydraulic tank front plate is attached to the side plate - see the illustration below.
Repair procedures are available for all crack locations, and are detailed below.
Use The Following Weld Procedure For All Welding
Clean the area to be welded of oil, grease, paint and dirt. Welding operator personal protection should be provided to assure that total weld fume in the operator's breathing zone is within safe limits.
All repair-welding operators must be qualified as outlined in the current ANSI/AWS D1.1, or D14.3, or Caterpillar Manufacturing Practices MC1000-105 for the SMAW (Shielded Metal Arc Welding) process in the position used for repairing the tank. The welding operator must also have used this process during the last six months or be re-certified for this process before welding. Documentation must be maintained of the weld operator's qualifications.
The tank must be at a minimum temperature of 16 degrees C (60 degrees F) before and during all SMAW and GMAW welding.
The SMAW process shall be used with E7018 (ANSI/AWS A5.5) welding electrode. The weld deposited by these electrodes will have the following minimum mechanical properties:
420 MPa ( 60 KSI ) Yield Strength
22% elongation in 50 mm ( 2 inches )
27 J ( 20 ft lb. ) Notch Toughness at -29 degrees C (-20 F)
The following chart relates to the electrode
diameter and approximate current settings for welding.
| Diameter | Amps |
| 3 mm (0.125 in) | 130 |
| 4 mm (0.156 in) | 180 |
| 4.8 mm (0.166 in) | 260 |
Use the direct current electrode positive (DC reverse polarity) setting and remove the slag after every pass.
As an alternate process the GMAW process may be used with ER70S-3 (A5.18) welding electrode and the manufacturers' specified shielding gas(es). The weld deposited by these electrodes will have the following minimum mechanical properties:
420 MPa ( 60 KSI ) Yield Strength
22% elongation in 50 mm ( 2 inches )
27 J ( 20 ft lb. ) Notch Toughness at -18 degrees C (0 F)
| Wire Feed Speed | Voltage | Approximate Amperage: |
| Minimum 200 IPM | 24 | 210 |
| Optimum 275 IPM | 28 | 250 |
| Maximum 325 IPM | 29 | 300 |
Use the direct current electrode positive (DC reverse polarity) setting and remove the slag after every pass.
Attach the welding ground cable directly to the tank. Do not allow welding current to travel through the machine's bearings or hydraulic cylinders. Protect all hydraulic cylinders, struts, hoses, and machined surfaces from sparks or spatter produced by the welding, chipping, and/or grinding operations.
Weld the joint using stringer beads or a weave pattern as desired. The welding pass size should be manageable, and generally, not exceed two times the electrode diameter. With a single pass of 1/8 inch E7018, the weld metal should be two times the electrode diameter. If the GMAW process is used the welding pass size should not exceed 8mm (0.312-inch) fillet volume.
| Part Number | Description | Quantity |
| 188-7298 | Gasket | 1 |
| 150-5939 | Adapter | 1 |
| 132-8876 | Filter Element | 3 |
| Item 1 | Plate | 1 |
| Item 2 | Plate | 1 |
| Item 3 | Plate | 1 |
Machine Preparation
1. Left Side Plate Repair
1. Remove all dirt, oil, grease and paint from the areas to be welded.
2. Remove the oil level gauge.
3. Inspect the area for cracks. Where cracks are present, use dye penetrant to identify the extent of the crack then carry out weld repairs as required. Dress the welded area flush to the tank face.
4. Manufacture Item 1 Plate using the dimensions and specifications provided below - all dimensions are in millimeters.
5. Position the Item 1 Plate on the left side
of the hydraulic tank, using the cut-out slot for the oil level gauge to
correctly position the plate - the gauge mounting holes in the hydraulic
tank should be positioned centrally in the slot and at equal distances
from the upper and lower radii of the slot - see the illustration below.
Note that the side face of the tank may have bowed and it may be necessary
to push the plate flush to the tank face
6. Secure the plate to the side face of the
tank using 4mm fillet welds completely around the outside edge of the plates
and in the 4 vertical and 6 horizontal pockets in the plate. Add a "capping"
weld across the fillet welds in the 6 horizontal pockets - see the illustration
below. Ensure there are no stops and starts in the weld runs.
7. Clean all weld spatter from the level gauge area and reinstall the gauge using a new 150-5939 Adapter kit. Torque the retaining screws to 7 Nm maximum.
2. Front Plate Repair
1. Remove all dirt, oil, grease and paint from the areas to be welded.
2. Inspect the area for cracks. Where cracks are present, use dye penetrant to identify the extent of the cracks, then carry out weld repairs as required. Dress the welded area flush to the tank face.
3. Manufacture Item 2 Plate, using the dimensions and specifications provided below - all dimensions are in millimeters.
4. Position the plate on the front face of
the hydraulic tank so there are 70mm gaps between the left and right hand
edges of the plate and the left and right hand walls of the tank structure,
and also so there is a 70mm gap between the bottom edge of the plate and
the top of the battery support plate - see illustration below. Note that
the front face of the tank may have bowed and it may be necessary to push
the plate flush to the tank face.
5. Secure the plate to the front face of the
tank using a 4mm fillet weld completely around the outside edge of the
plate and in the 3 vertical and 6 horizontal pockets in the plate. Ensure
there are no stops and starts in the weld runs. To provide additional bracing
in the area where the inner baffle plate meets the tank outer skin, add
a capping weld across the fillet welds in the 6 horizontal pockets (shown
in the illustration below) to complete the front plate installation.
6. Once the front plate has been installed, reweld the internal baffle to the inside front face of the hydraulic tank using a continuous 3mm fillet weld in place of the original stitch welds - see the illustrations below. It is not necessary to weld on both sides of the baffle - just the side that was stitch welded.
3. Battery Support Plate Repair
1. Thoroughly clean the area around the joint between the battery support plate and the front plate of the hydraulic tank to remove all dirt, oil and grease from the areas to be inspected and, where required, welded.
2. Check to see if tack welds have been applied
at the radiused edge between the battery plate and the hydraulic tank front
plate - see illustration below.
4. When the cracks have been repaired, apply a 4mm fillet weld completely around the outside edge of the joint where battery support plate meets the hydraulic tank front plate, welding it to the front of the hydraulic tank - see illustrations below. Ensure there are no stop/starts in the weld run.
4. Right Side Plate Repair
1. Remove all dirt, oil, grease and paint from the areas to be welded.
2. Inspect the area for cracks. Where cracks are present, use dye penetrant to identify the extent of the crack then carry out weld repairs as required. Dress the welded area flush to the tank face.
3. Manufacture Item 3 Plate using the dimensions
and specifications provided below - all dimensions are in millimeters.
4. Position the Item 3 Plate on the right-hand
side of the hydraulic tank, using the cut-out for the brake pump supply
hose adapter to correctly position the plate on the side of the tank -
see the illustrations below. Note that the side face of the tank may have
bowed and it may be necessary to push the plate flush to the tank face.
5. Secure the plate to the right-hand face of the tank using a 4mm fillet weld completely around the outside edge of the plate, in the 2 vertical pockets in the plate and around the cut-out for the brake pump supply hose adapter. Ensure there are no stops and starts in the weld runs.
Repair Completion and Machine Reassembly
Remove all weld spatter and slag from all repaired areas of the hydraulic tank.
Thoroughly clean and dry the inside of the hydraulic tank - it is essential that all dirt / foreign material is removed from the inside of the tank so care should be taken to ensure all weld debris is removed.
Replace the 3 x 132-8876 filter elements in the tank top cover assembly and reinstall the assembly into the tank using a new 188-7298 Gasket.
Fit appropriately sized blanking plugs to all open ports, then repaint the tank as required.
Referring to the Operation and Maintenance Manual, and the procedures detailed in RENR5140 - Disassembly and Assembly, 735, 740 and 740 Ejector Articulated Truck Machine Systems - reinstall the hoist and brake systems hydraulic tank.
Start the machine and perform a systems operation test.
Check the tank for oil leaks.
Referring to the procedures detailed the Operation and Maintenance Manual, and in RENR5140 - Disassembly and Assembly, 735, 740 and 740 Ejector Articulated Truck Machine Systems - reassemble the machine complete.
GROUP 2 REWORK PROCEDURE
Oil Tank on 735, 740 and 740 Ejector Articulated Trucks
Problem Description - Group 2 Machines
Cracks may develop on the right-hand side plate of the hoist and brake systems hydraulic oil tank on certain 735, 740 and 740 Ejector Articulated Trucks.
The cracks may develop where the hydraulic
tank front plate is attached to the side plate - see the illustration below.
Use the procedure detailed below to repair any crack that has developed in this location.
Use The Following Weld Procedure For All Welding
Clean the area to be welded of oil, grease, paint and dirt. Welding operator personal protection should be provided to assure that total weld fume in the operator's breathing zone is within safe limits.
All repair-welding operators must be qualified as outlined in the current ANSI/AWS D1.1, or D14.3, or Caterpillar Manufacturing Practices MC1000-105 for the SMAW (Shielded Metal Arc Welding) process in the position used for repairing the tank. The welding operator must also have used this process during the last six months or be re-certified for this process before welding. Documentation must be maintained of the weld operator's qualifications.
The tank must be at a minimum temperature of 16 degrees C (60 degrees F) before and during all SMAW and GMAW welding.
The SMAW process shall be used with E7018 (ANSI/AWS A5.5) welding electrode. The weld deposited by these electrodes will have the following minimum mechanical properties:
420 MPa ( 60 KSI ) Yield Strength
22% elongation in 50 mm ( 2 inches )
27 J ( 20 ft lb. ) Notch Toughness at -29 degrees C (-20 F)
The following chart relates to the electrode
diameter and approximate current settings for welding.
| Diameter | Amps |
| 3 mm (0.125 in) | 130 |
| 4 mm (0.156 in) | 180 |
| 4.8 mm (0.166 in) | 260 |
Use the direct current electrode positive (DC reverse polarity) setting and remove the slag after every pass.
As an alternate process the GMAW process may be used with ER70S-3 (A5.18) welding electrode and the manufacturers' specified shielding gas(es). The weld deposited by these electrodes will have the following minimum mechanical properties:
420 MPa ( 60 KSI ) Yield Strength
22% elongation in 50 mm ( 2 inches )
27 J ( 20 ft lb. ) Notch Toughness at -18 degrees C (0 F)
| Wire Feed Speed | Voltage | Approximate Amperage: |
| Minimum 200 IPM | 24 | 210 |
| Optimum 275 IPM | 28 | 250 |
| Maximum 325 IPM | 29 | 300 |
Use the direct current electrode positive (DC reverse polarity) setting and remove the slag after every pass.
Attach the welding ground cable directly to the tank. Do not allow welding current to travel through the machine's bearings or hydraulic cylinders. Protect all hydraulic cylinders, struts, hoses, and machined surfaces from sparks or spatter produced by the welding, chipping, and/or grinding operations.
Weld the joint using stringer beads or a weave pattern as desired. The welding pass size should be manageable, and generally, not exceed two times the electrode diameter. With a single pass of 1/8 inch E7018, the weld metal should be two times the electrode diameter. If the GMAW process is used the welding pass size should not exceed 8mm (0.312-inch) fillet volume.
| Part Number | Description | Quantity |
| 188-7298 | Gasket | 1 |
| 150-5939 | Adapter | 1 |
| 132-8876 | Filter Element | 3 |
| Item 3 | Plate | 1 |
Referring to the Operation and Maintenance
Manual, and the procedures detailed in RENR5140 - Disassembly and Assembly,
735, 740 and 740 Ejector Articulated Truck Machine Systems - remove the
hoist and brake systems hydraulic tank. Thoroughly clean the outside of
the tank in preparation for repairs. Remove the top cover assembly from
the tank.
Plate Repair Procedure
1. Remove all dirt, oil, grease and paint from the areas to be welded.
2. Inspect the area for cracks. Where cracks are present, use dye penetrant to identify the extent of the crack then carry out weld repairs as required. Dress the welded area flush to the tank face.
3. Manufacture Item 3 Plate using the dimensions
and specifications provided below - all dimensions are in millimeters.
4. Position the Item 3 Plate on the right-hand
side of the hydraulic tank, using the cut-out for the brake pump supply
hose adapter to correctly position the plate on the side of the tank -
see the illustrations below. Note that the side face of the tank may have
bowed and it may be necessary to push the plate flush to the tank face.
5. Secure the plate to the right-hand face of the tank using a 4mm fillet weld completely around the outside edge of the plate, in the 2 vertical pockets in the plate and around the cut-out for the brake pump supply hose adapter. Ensure there are no stops and starts in the weld runs.
Repair Completion and Machine Reassembly
Remove all weld spatter and slag from all repaired areas of the hydraulic tank.
Thoroughly clean and dry the inside of the hydraulic tank - it is essential that all dirt / foreign material is removed from the inside of the tank so care should be taken to ensure all weld debris is removed.
Replace the 3 x 132-8876 filter elements in the tank top cover assembly and reinstall the assembly into the tank using a new 188-7298 Gasket.
Fit appropriately sized blanking plugs to all open ports, then repaint the tank as required.
Referring to the Operation and Maintenance Manual, and the procedures detailed in RENR5140 - Disassembly and Assembly, 735, 740 and 740 Ejector Articulated Truck Machine Systems - reinstall the hoist and brake systems hydraulic tank.
Start the machine and perform a systems operation test.
Check the tank for oil leaks.
Referring to the procedures detailed the Operation and Maintenance Manual, and in RENR5140 - Disassembly and Assembly, 735, 740 and 740 Ejector Articulated Truck Machine Systems - reassemble the machine complete.