VALVE GP-CONTROL 8Y6734 - Caterpillar

1. Lift the bucket and put tooling (A) in position under the lift arm for support. Move the control lever and lower the weight of the lift arms and bucket on tooling (A) as shown.
Stop the engine, move all control levers backward and forward to release the pressure in the hydraulic system. Slowly loosen the cap to release any pressure in the hydraulic tank. Let the hydraulic oil become cool before any lines are disconnected in the hydraulic system.
VIEW FROM UNDER MACHINE2. Disconnect hose assemblies (1) and (2) from inside the front frame. 3. Remove bar (3) that holds the rod pin.4. Fasten a hoist to the lift cylinder.5. If necessary use tool (B) to clean the threads of the rod pin. 6. Install tool (C) and remove the rod pin from inside of the lift arm. 7. Remove bar (4) that holds the cylinder pin in the frame.8. If necessary use tool (B) to clean the threads in the cylinder pin (5). Use tool (C) and remove the cylinder pin.9. Remove the lift cylinder. The weight of the cylinder is 168 lb. (76 kg).Install Lift Cylinders
1. Pull the rod (1) almost all of the way out of the cylinder.2. Fasten a hoist to the lift cylinder and put it in position on the machine. 3. Install pins (2) and (3) to hold the cylinder in position. Install the bars to hold pins (2) and (3).
VIEW FROM UNDER MACHINE4. Put clean hydraulic oil on the O-ring seals and connect hose assemblies (4) and (5) to the lift cylinder.5. Put clean grease in the cylinder pins.6. Remove tooling (A) from under the lift arms and lower the bucket to the ground.7. Fill the hydraulic system with oil to the correct level.Disassemble Lift Cylinders
start by:a) remove lift cylinders1. Fasten a hoist to the lift cylinder and put it in position on tooling (A). 2. Remove tube assemblies (1) and (2) from the cylinder assembly. 3. Remove seals (3) from each side of the rod assembly. 4. Use tooling (B) to pull the bearing out of the rod assembly. 5. Remove seals (4) from each side of the cylinder assembly. 6. Use tooling (C) to pull the bearings and spacer from the cylinder assembly. 7. Make sure support (6) is in position under the rod and fasten strap (5) around the rod to hold it.8. Put a mark on the head and cylinder assembly for correct alignment at assembly. Remove four bolts (7).9. Pull the cylinder away from the rod and head with tooling (A). 10. Use tooling (D) to remove the nut that holds piston (8) on the rod. Remove piston (8) from the rod. 11. Remove wear ring (9) and seal assembly (10) from the piston. 12. Remove head (11) from the rod.13. Remove the back-up ring and O-ring seal (12) from head (11). 14. Remove three seals (13) from head (11).Assemble Lift Cylinders
TYPICAL EXAMPLE1. Use tool (A) to install seal (4) in head (1).2. Install seal (3)