Repair of the Lift Arm Assembly Crossmember{0679, 6107, 6119} Caterpillar

Wheel Loader:

950B (S/N: 31R1-UP)

950B (S/N: 63R1-UP)

950B (S/N: 65R1-UP)

950B (S/N: 22Z1-3188,3189-UP)

950E (S/N: 63R1-UP; 65R1-UP; 22Z1-3188,3189-UP)

950F Series II (S/N: 4DJ1-UP; 5SK1-UP; 8TK1-UP; 2LM1-UP)

950F (S/N: 7ZF1-UP; 6YG1-UP)

950G Series II (S/N: BAA1-UP; AYB1-UP; AYD1-UP; AYL1-UP; AXR1-UP; AYS1-UP; AXX1-UP)

950G (S/N: 2JS1-UP; 4BS1-UP; 6NS1-UP; 3JW1-UP; 5FW1-UP; 5MW1-UP; 8JW1-UP)

950H (S/N: N1A1-UP; M1G1-UP; J5J1-UP; K5K1-UP)

960F (S/N: 9ZJ1-UP; 4CL1-UP; 1YM1-UP)

962G Series II (S/N: BAB1-UP; BAC1-UP; BAD1-UP; AYE1-UP; AYG1-UP; AXS1-UP; AXY1-UP)

962G (S/N: BDP1-UP; 3BS1-UP; 5RS1-UP; 4PW1-UP; 6EW1-UP; 6HW1-UP; 7BW1-UP)

962H (S/N: N4A1-UP; M3G1-UP; J6J1-UP; K6K1-UP)

966C (S/N: 18B1-UP; 78G1-UP; 42J1-UP; 76J1-UP; 30K1-UP; 25U1-UP)

966D (S/N: 35S1-2523; 94X1-UP; 99Y1-UP)

966E (S/N: 2FD658-UP; 35S1-2523; 94X1-UP; 99Y1-UP)

966F Series II (S/N: 8BG1-UP; 1SL1-UP)

966F (S/N: 3XJ1-UP; 6ML1-UP; 7HL1-UP)

966G Series II (S/N: AXJ1-UP; AXL1-UP; ANT1-UP; AWY1-UP; ANZ1-UP; AWZ1-UP)

966G (S/N: AAH1-UP; HDH1-UP; 3ZS1-UP; 9RS1-UP; 3PW1-UP; 3SW1-UP; 8XW1-UP)

966H (S/N: A6D1-UP; A6G1-UP; A6J1-UP; FMW1-UP)

970F (S/N: 7SK1-UP; 9JK1-UP)

972G Series II (S/N: AXC1-UP; AXE1-UP; AXN1-UP; AWP1-UP; AXP1-UP; ANY1-UP)

972G (S/N: TLA1-UP; 7LS1-UP; 8TS1-UP; AAW1-UP; 1EW1-UP; 4WW1-UP; 6AW1-UP; 9GW1-UP)

972H (S/N: A7D1-UP; A7G1-UP)

980C (S/N: 13B1-UP; 2EB1-UP; 2XD1-UP; 63X1-UP)

980F Series II (S/N: 5XJ1-UP; 4RN1-UP; 8JN1-UP)

980F (S/N: 8CJ1-UP; 3HK1-UP)

980G Series II (S/N: AXG1-UP; AWH1-UP; AYT1-UP)

980G (S/N: 9CM1-UP; 2KR1-UP; 2SR1-UP)

980H (S/N: MHG1-UP; A8J1-UP; JMS1-UP)

988B (S/N: 50W1-UP; 62Y1-UP)

992C (S/N: 42X1-UP; 49Z1-UP)

Introduction

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Personal injury or death can result from fumes, gases and ultraviolet rays from the weld arc. Welding can cause fumes, burn skin and produce ultraviolet rays. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing area. Wear eye, ear and body protection before working. Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can cause death. Read and understand the manufacturer's instructions and your employer's safety practices. Do not touch live electrical parts. See "American National Standard Z49.1, Safety in Welding and Cutting" published by the American Welding Society. American Welding Society 2501 N.W. 7th Street Miami, Florida 33125 See "OSHA Safety and Health Standards, 29 CFR 1910", available from U.S. Department of Labor. U.S. Department of Labor Washington, D.C. 20210

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Personal injury can result from flame cutting or welding on painted areas. The effect of gasses from burned paint is a hazard to the person doing the cutting or welding. Do not flame cut or weld on painted areas.

Some wheel loaders may develop cracks in the crossmember of the lift arm assemblies. Cracking occurs in the welds between the tube that is on the crossmember or the tilt lever support bracket. This Special Instruction outlines repair procedures for the lift arm assembly crossmember. Weld the cracks and casting defects that can be repaired. Successful repairs to the crossmember will depend on the extent of the required repair. The repair methods that are being utilized will determine the success of the repair. The repair quality determines the success of the repair.

Note: The repairs should be made with the lift arm assembly heated to a temperature of 10 °C (50 °F) or above. Remove all of the paint, oil and grease from weld locations. Preheat the area to be repaired to a temperature of120 °C (248 °F) if the part is less than 76.2 mm (3.0 inch) thick or 150 °C (302 °F) if it is 76.2 mm (3.0 inch) or thicker in order to eliminate the potential for hydrogen gas pocket and to reduce stress.

Note: The welds also need to be heat treated to a temperature of 595 °C (1103 °F) at a rate of one hour per 25.4 mm (1.0 inch) based on the widest part of the area.

Note: Repairs to lift arm assemblies that had the crossmembers quenched and tempered are recommended for the type 1 repairs only. Refer to Table 1. The numbers listed in table 1 are the part numbers that are cast in to the crossmembers

Illustration 1	g01339267
The illustration is a 980H lift arm assembly. The locations of the crossmembers that are cracking are typical for other models. The guidelines for the welding repair process is the same. (1) Weld between the crossmember and side arms. (2) Crossmember casting. (3) Crossmember casting and tilt lever brackets.

Note: Reference the inside frame dimension chart for the A and the B dimensions.

Type 1 Crack Repair

Illustration 2	g01307664

Cracks in the crossmember to the side arm welds.

(1) Weld preparation area

(2) Surface crack in weld

(3) Weld defects

(4) Crossmember

(5) Side arm

(6) Welds

1. Clean the cracked area thoroughly.

2. Repair the crack and remove any weld defects with an air carbon arc torch or a similar tool.

3. When all of the weld defects have been removed (both length and depth), use a rotary file to trim the groove to eliminate any undercuts, carbon, and to provide at least a 45° opening.

4. To eliminate distortion, do not weld more than 457 mm (18 inch) at a time.

5. If the weld defect is less than 200 mm (7.87 inch) in length, spreader bars are not needed to minimize distortion of the lift arms.

6. Spreader bars are recommended if the weld defects in the front and rear quadrants are more than 200 mm (7.87 inch) in length. Refer to the illustration at the beginning of this instruction.

7. The distance between the lift arm pin bore surfaces should be spread 12.7 mm (0.5 inch) before any welding is performed

8. If the spreader bars are needed, use a section of tubing that has an 12.7 mm (0.5 inch) inner diameter. A wall thickness of 12.7 mm (0.5 inch) is required. This can be used as a spreader bar.

9. Use a hydraulic jack that has a capacity of at least 900 kN (202329.0000 lb) of force to put the spreader bar in position.

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Personal injury or death can result from the hydraulic jack slipping. The hydraulic jack can slip unexpectedly causing injury. To avoid possible injury or death use caution when a hydraulic jack is used to install a spreader bar.

10. Make the repairs by using a weld from the following chart as a guide to select the filler metal.
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    Table 2

    Weld Processes and Fillet Material.
    Weld Process.	AWS Specs	Manufacturer	Caterpillar Part Number
    SMAW	A5.5 E10018-D2	Lincoln	-
    GMAW	A5.18-79 ER7053	Lincoln	L-50.62 1U-6369
    FCAW (Gas Shielded)	A5.20 E70T-1	Alloy Rod	111AC 1/16 1U-5315
    FCAW (Gas Shielded)	A5.20 E70T	Alloy Rod	111AC 3/32 1U-5317
    FCAW (Gas Shielded)	A5.20 E70T	Alloy Rod	111HD 3/32 1U-5237
    FCAW (Gas Shielded)	A5.20 E70T	Alloy Rod	11-70 1/16 1U-5244

11. Allow the welds to cool down between each pass, maintain an interpass temperature of 38 °C (100.4 °F).

12. All welding must be done in a flat or a horizontal position. The maximum width of the weld bead is 12.7 mm (0.5 inch).

13. The weld grooves should be prepared and filled with the weld material. The contour of the weld should match the original weld profile.

14. Grind the repaired area to ensure a smooth transition between the casting and side plate.

15. After the repairs have been completed, inspect the frame assembly for the correct inside dimensions. See the following chart for the correct dimensions.
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    Table 3

    Inside Frame Dimensions (Plate to Plate)
    Model	Lift Arm - Frame End (A)	Lift Arm Bucket End (B)
    992C	1291.8 mm (50.86 inch)	1342.6 mm (52.86 inch)
    988B	1066.8 mm (42 inch)	1123.7 mm (44.24 inch)
    980C - 980H	900 mm (35.43 inch)	900 mm (35.43 inch)
    972G	970 mm (38.19 inch)	938 mm (36.931 inch)
    972H	930 mm (36.61 inch)	940.6 mm (37.03 inch)
    970F	880 mm (34.65 inch)	896 mm (35.28 inch)
    966C	641.1 mm (25.24 inch)	993.7 mm (39.12 inch)
    966D, 966E, 966F	880 mm (34.645 inch)	890 mm (35.04 inch)
    966G, 966H	930 mm (36.61 inch)	940 mm (37.00 inch)
    962G, 962H	850 mm (33.46 inch)	863 mm (33.98 inch)
    950B, 950H	850 mm (33.46 inch)	863 mm (33.98 inch)

Repairing the cracks in the crossmember casting.

Note: High quality weld repairs of the cracks in the crossmember are required in order to provide acceptable service life after the crossmember has been repaired. Failure to eliminate all casting defects such as the introduction of weld slag, porosity or lack of fusion, will result in reduced service life of the crossmember after the repairs have been made.

Type 2 Crack Repair

Cracks in the tube section of the crossmember casting.

Note: Repairs to lift arm assemblies with quenched crossmembers and with tempered crossmembers are not recommended for this type of repair. Please consult with the dealer or consult with the manufacturer before making this repair.

Note: This procedure does not apply to the fabricated crossmember.

Illustration 3	g01308931
Crossmember repair (1) Crack. (2) Weld preparation. (3) Casting used as backup material.

1. Clean the area that is being repaired thoroughly. use an air carbon arc torch, or a similar tool to gouge out the area of the crack and casting defect.

2. Refer to illustration 3. Cracks that are less than 75 percent of the casting wall thickness should be prepared for welding by using a rotary file. Complete the weld processes by using the weld that is listed in table 2.

Illustration 4	g01309183
Crossmember repair (crack through crossmember). (4) Crack (5) Backup material

3. If the crack or the casting defect extends through the crossmember wall thickness, an opening must be made and a backup strip installed. Make the opening large enough to install 4.8 mm (0.189 inch) thick backup strips.

4. Place the metal strips through the opening and tack weld the strip into position.

5. Preheat the area to a temperature of 120 °C (248 °F) if the part is less than 76.2 mm (3.0 inch) thick or 150 °C (302 °F) if it is 76.2 mm (3.0 inch) or thicker in order to eliminate the potential for hydrogen gas pocket and reduce the stress.

6. Completely fill the groove with the weld. Use one of the welding processes that are listed. SMAW A5.5 E10018-D2 electrode is preferable. Multiple weld passes are preferred so that there are extra welds above the surface. Allow the welds to cool down between passes, maintain a interpass temperature of 38 °C (101 °F)

7. Grind down the extra welds in the repaired area so that it blends in with the casting profile. All welds must be free of undercuts, porosity, and cracks.

8. Avoid high grinding pressures that may cause excessive heat and discoloration of the weld material.

9. Upon the completion of welding, perform the post weld heat treatment to the welds at a temperature of 595 °C (1103 °F) at a rate of one hour per 25.4 mm (1.0 inch) based on the widest part of the area.

10. With a standard ball peen hammer or a pneumatic needle scaler peen the service area. Peen the service area in order to improve the fatigue life of the crossmember repairs. Peening is used to counteract metal shrinkage which occurs upon cooling.

Type 3A Repair

Crack in the tilt Lever support bracket that are less than 31.75 mm (1.25 inch) in depth.

Illustration 5	g01309477
Crossmember/Tilt lever brackets (6) Crack 31.75 mm (1.25 inch) maximum depth.

Note: Repairs to the lift arm assemblies that had their crossmembers quenched and tempered are not recommended for this type of repair. Please connsult with the caterpillar dealer or the manufacturer before a repair is made.

Note: This procedure does not apply to the fabricated crossmembers.

1. Clean the area to be repaired thoroughly. With an air carbon arc torch or similar tool, gouge out the crack to create a 60° single vee. Use a rotary file to remove any rough surface and foreign material. Check the area to make sure it is clean and that the crack has been completely removed.

2. Pre heat the area to a temperature of 120 °C (248 °F) if the part is less than 76.2 mm (3.0 inch) thick or 150 °C (302 °F) if it is 76.2 mm (3.0 inch) or thicker in order to eliminate the potential for hydrogen gas pocket and reduce the stress.

3. Completely fill the groove with weld by using one of the weld processes earlier (SMAW A5.5 E10018-D2 electrode is preferable). Multiple weld passes are preferred so that there are extra welds above the surface.

4. Allow the welds to cool slowly between each pass, maintaining an interpass temperature of 38 °C (101 °F).

5. Grind down the extra welds in the repaired area so that it blends in with the casting profile. All welds must be free of undercuts, porosity, and cracks.

6. Avoid high grinding pressures that may cause excessive heat and discoloration of the weld material.

7. Upon the completion of welding, perform the post weld heat treatment to the welds at a temperature of 595 °C (1103 °F) at a rate of one hour per 25.4 mm (1.0 inch) based on the widest part of the area.

8. Peening with a standard ball peen hammer or a pneumatic needle scaler is recommended to help improve the fatigue life of the crossmember. Peening is used to counteract metal shrinkage which occurs upon cooling.

Type 3B Repair

Repair of cracks in the tilt lever support brackets that are deeper than 31.75 mm (1.25 inch).

Illustration 6	g01309685
Tilt lever repairs (7) Weld preparation (8) Crack that is deeper than 31.75 mm (1.25 inch)

Note: This repair is not recommended for cracks that propagate deeper than 63.5 mm (2.5 inch). This repair is not recommended for cracks that extend into the the tilt lever, web or if the tilt lever it is completely broken.

Note: The lift arm assembly should be heated to a temperature of 10 °C (50 °F) or above.

Note: Repairs to the lift arm assemblies that had the their crossmembers quenched and their crossmembers tempered anr not recommended for this type of repair. Please consult with the dealer or consult with the manufacturer before making this repair.

Note: This procedure does not apply to the fabricated crossmembers.

1. Clean the area to be repaired thoroughly. With an air carbon arc torch or similar tool, gouge out the crack to create a 60° single Vee. The depth of the Vee should be one half of the thickness of the flange. Refer to illustration 6.

2. Use a rotary file to remove any rough surface and foreign material. Check the area to make sure it is clean and that the crack has been completely removed.

3. Preheat the area to a temperature of 120 °C (248 °F) if the part is less than 76.2 mm (3.0 inch) thick or 150 °C (302 °F) if it is 76.2 mm (3.0 inch) or thicker in order to eliminate the potential for hydrogen gas pocket and reduce the stress.

Illustration 7	g01309782
Tilt lever repairs. (9) First weld

4. First fill the groove to one half the depth of the groove by using one of the weld processes listed earlier (SMAW A5.5 E10018-D2 electrode is preferable). Refer to illustration 7. Alternate the weld passes in order to minimize heat and distorttion.

Illustration 8	g01309873
Tilt lever repairs (10) Second weld. (11) Third weld. (12) Fourth weld.

5. Air carbon arc out the opposite side of the arm to remove the crack and form a 60° vee. Air carbon arc the material until the bottom of the groove is in the repair weld material of the first side.

6. Secondly, fill the groove to one half the depth of the groove by using one of the weld processes listed earlier (SMAW A5.5 E10018-D2 electrode is preferable). Refer to illustration 8. Alternate the weld passes in order to minimize heat and distorttionRefer to illustration

7. Allow the welds to cool slowly between each pass, maintaining an interpass temperature of 38 °C (101 °F)

8. Alternate the welds from side-to-side as shown in the illustration 8. Make sure that the multiple passes are such that there are extra welds above the surface.

9. Grind down theextra welds in the repaired area until the surface is smoth and the area matches the profile of the tilt lever. All welds must be free from undercuts, porosity and cracks.

10. Avoid high grinding pressures that may cause heat and discoloration of the weld material.

11. Upon completion of the welding perform the post weld heat treatment to the welds at a temperature of 595 °C (1103 °F) att a rate of one hour per 25.4 mm (1 inch) that is based on the widest part of the area.

12. Peening with a standard ball peen hammer or a pneumatic needle scaler is recommended to help improve the fatigue life of the crossmember. Peening is used to counteract metal shrinkage which occurs upon cooling.