HEAD 9T8221 - Caterpillar

If the main relief valve is to be removed from the implement control valve on the machine, release all the pressure from the hydraulic system before any work is done to prevent possible personal injury.
1. Remove bolts (1) and main relief valve (2) from the implement control valve. 2. Remove valve (3), spring (6) and O-ring seals (5) from body group (4). 3. Remove the bolts, valve group (12), stem (11), stop (10), spring (9), valve (8), spring (16), retainer (15) and spool (14) from body group (13).4. Remove the shims from stem (11) and O-ring seals (7) and (17) from valve groups (12) and (13).Install Implement Control Main Relief Valve
1. Clean and inspect all parts of the implement control main relief valve. Make a replacement of any parts that are worn or damaged. 2. Put O-ring seals (1) and (10) in position on valve groups (6) and (11).3. Install the original shims in stem (5).4. Install valve (2), spring (3), stop (4), stem (5), valve (7), retainer (8), spring (9) and valve group (11) on valve group (6). Install the bolts that hold the valve together. 5. Install O-ring seals (14), valve (13) and spring (15) in valve group (12). 6. Put valve group (12) and valve body (6) in position on the implement control valve as shown, and install the bolts that hold them. Tighten bolts to a torque of 82 3 N m (60 2 lb.ft.).