Replacement of Lift Arm Crossmembers on Wheel Loaders{6107, 6119} Caterpillar

Wheel Loader:

950B (S/N: 31R1-UP; 63R1-6053; 65R1-3087,3088-UP)

950E (S/N: 63R6054-UP)

950F (S/N: 6YG1-UP; 4DJ1-2074)

950F Series II (S/N: 5SK1-UP; 8TK1-UP; 2LM1-UP; 4DJ2075-UP)

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

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

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

960F (S/N: 9ZJ1-UP; 4CL1-UP; 6XL1-UP; 1YM1-UP)

962G (S/N: 3BS1-UP; 5AS1-UP; 5RS1-UP; 9BS1-UP)

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

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

966C (S/N: 18B1-UP; 9KC1-UP; 78G1-UP; 42J1-UP; 76J1-UP; 30K1-UP; 25U1-UP)

966D (S/N: 35S1-2522; 99Y1-5314,5315-UP)

966E (S/N: 35S2523-UP; 2FD1-657,658-UP)

966F (S/N: 4YG1-UP; 3XJ1-UP; 6ML1-UP; 7HL1-UP)

966F Series II (S/N: 9YJ1-UP; 1SL1-UP; 8BG1-UP)

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

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

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

970F (S/N: 7SK1-UP; 9JK1-UP; 7PL1-UP)

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

972G Series II (S/N: TLA1-UP; AXC1-UP; AXE1-UP; AXN1-UP; AWP1-UP; AXP1-UP; ANY1-UP)

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

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

980F (S/N: 8CJ1-UP; 3HK1-UP; 5XJ1-UP)

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

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

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

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

988B (S/N: 50W1-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.

Premachined lift arms are now available on many of the models that are listed. Heat treated crossmembers are available for field service. Use the following procedures in order to replace severely cracked crossmembers. Reference the Parts Manual, and the Service manual. Reference the Special Instruction, SMHS8433.

Note: Clean all surfaces before parts are installed.

Do not perform any procedure in this instruction or order any parts until you understand the information that is contained in this instruction.

Note: All heat treated crossmembers are premachined. Finished boring is required. Refer to the Service Manual for the machine.

Installation of the Reinforcement

Illustration 1	g01306070
(A) Cross ties that are Horizontal. (B) Cross ties that are Vertical.

1. The use of steel that is solid, square, and hot rolled. This square steel stock should be 102 mm (4.0 inch). Weld the cross support to the lift arms, as shown. Weld the cross ties to the welded cross supports. Weld one cross tie on the front and one cross tie on the back of the cross supports. Use a section of the 102 mm (4.0 inch) stock and weld stock into the center gap between the cross ties.

Illustration 2	g01306210
(C) Lift Arm (D) Cross support (E) No weld (F) Fillet weld

Note: The location of the support is not critical. Be sure to allow enough room to weld.

Illustration 3	g01306236
(D) Cross Support (G) Spreader Bar location (H) V-Bracket (J) Crossmember Bore Bar (K) Lift Arm (L) Vertical Cross ties (M) Fillet Weld (N) Locator Fixture

2. Insert a bar with the same diameter as the crossmember bore, and support bar with a V-bracket. Weld the bracket to the bracket to the lift arms as shown above.

3. Weld the locator bars to the cross ties. These bars help to locate the new crossmember. By using the V-bracket and locator bars, you will be able to position the new crossmember and maintain the correct F-pin joint location as well as the orientation of the new crossmember.

Crossmember Removal and Installation

1. Remove the bore bar and cut out the old crossmember.

2. Make sure the surface where the new crossmember will be welded is free from cracks, undercuts and splatters. The surface should be ground smooth and flush.

3. Install the new crossmember by using a V-Bracket and the locator bars.

4. Position the lift arms so that the new crossmember will be welded vertically.

5. Place a 2.38 mm (0.10 inch) diameter soft wire stick electrode between the crossmember and lift arm that is spaced diagonally at 152 mm (6.0 inch). Be sure that the 2.38 mm (0.10 inch) wire is far enough under the J-groove weld on the crossmember, so that the wire does not melt during the welding.

   Note: The lift arms may be expanded in order to install the crossmembers.

Illustration 4	g01306309
(P) Crossmember (Q) Side Plate Assembly (R) Groove Weld (F) Fillet Weld (S) Soft Wire Spacers (T) A smooth transition of the fillet weld to the crossmember casting and the side plate. (U) Make six 20 mm (0.79 inch) fillet weld passes along each side before attempting to spread the lift arm. (V) Use a butter bead weld on the full length of the groove and the fillet weld.

6. Using AWS A5.20 Class E70T-5 Electrode, lay in a butter bead weld on the lift arm. You may use alloy rods T-75 flux core wire with CO2 shielding gas or equivalent.

Note: If aSMAW A5.5 Class E10018-D2 Electrode is used for the butter bead weld, preheat the lift arm to 204°C (400°F) and maintain the lift arm temperature at 149°C (300°F) to eliminate hydrogen gas pocket potential and reduce the stress.

7. Weld the first of six passes using AWS A5.20 Class E70T-1 (low hydrogen) Electrode or equivalent. Refer to the figure above for start/stop zones, initial weld passes, and final weld passes. All other start/stop points should be staggered.

   Note: Points (W), (X), (Y), and (Z) are start/stop zones for the initial and final weld passes. Clean the weld area thoroughly after each pass.

8. All weld passes should follow the same direction on both sides to avoid scissoring action of lift arms.

9. Install jacks with 900 kN (202,329.0 lb) of force at both ends of the lift arms, then remove cross supports from step one. All tacks and notches on the lift arm side plate profile should be removed, ground smooth, and be free of porosity, slag and cracks.

10. Spread lift arms 25 mm (1.0 inch) from the inside face of the bearing surface. Install the spreader bars at each end that have a diameter of 127 mm (5.0 inch) or larger. Wall thickness of spreader bars should be 12.7 mm (0.5 inch) minimum.

Note: Do Not weld the spreader bars. Remove the jacks.

11. Finish welding the lift arms one side at a time.

12. Lift arms should have a tendency to pull in. Use the following procedure to relieve the stress.

    1. Use a rose bud tip with a outside diameter of 12.7 mm (0.5 inch) to 19 mm (0.74 inch). This is used for oxygen fuel torches.

    2. Heat a vertical area on the outside face of the lift arm. Heat one side at a time.

    3. Begin 25 mm (1.0 inch) down from the top profile, 152 mm (6.0 inch) to 254 mm (10.0 inch) from the crossmember in a 25 mm (1.0 inch) to 38 mm (1.5 inch) wide pattern.

    4. Heat this area until the metal of the lift arm is red. Then, move in intervals. Slowly heat the area all the way down 25 mm (1.0 inch) from the bottom edge.

    5. Repeat the procedure above for the other side.

    6. Repeat the procedure above each time. Move farther down the lift arm each time until the spreader bars fall out.

    7. Permit the lift arms to air cool. Lift arms may draw back while cooling.

If the lift arms draw in too much, repeat step 10 in order to spread the lift arms more than 25 mm (1.0 inch). If the lift arms do not come back far enough, repeat the heating procedure above on the inside of the lift arms.

Note: When welding the back side of the lift arms, avoid heating any machine surfaces directly.

13. Clean and paint all areas affected by the heating and welding.

Refer to the Service Manual for the installation of the lift area and the installation of the hydraulics for the machines that are listed.