WRENCH (7/8" & 15/16" HEX) 3B1285 - Caterpillar

Remove Pilot-Overspeed Valve
1. Remove cover (1) from the hydrostatic power control unit. 2. Remove oil lines (2) from the underspeed and pilot-overspeed valves. Put plugs in the oil line openings. 3. Remove bolts (3) from the linkage on the pilot valve stem.4. Disconnect rod end (4) from the power control unit linkage. 5. Remove bolts (5), and remove pilot-overspeed valve (6). Bolts (5) must be removed from the pilot-overspeed valve so there will be enough clearance to remove the valve from the hydrostatic power control unit.Install Pilot-Overspeed Valve
1. Put pilot-overspeed valve (1) in the position shown; then put bolts (2) in the valve. Install the pilot-overspeed valve the remainder of the way, and tighten the three bolts that hold it in place. 2. Put the linkage in position on the pilot valve stem, and install bolt (3) to hold it in place.3. Connect rod end (4) to the power control unit linkage. 4. Be sure the washers and seal on the oil lines are in the position shown. 5. Install oil lines (5) on the underspeed and pilot-overspeed valves.6. Install the cover on the hydrostatic power control unit.Disassemble And Assemble Pilot-Overspeed Valve
START BY:a. remove pilot-overspeed valve1. Disassemble and assemble the pilot valve stem as follows:a. Remove the two bolts that hold plate (1) in place. Remove pilot stem (5) from the valve body.b. Put spring (3) under compression, and remove retainers (2) and (4) from the stem. Remove spring (3) from the stem.c. If a replacement is necessary, remove rod end (6) from the stem.d. If the rod end was removed from the stem, install rod end (6) in stem (5) so dimension "X" is 27.7 0.5 mm (1.09 .02 in.), and tighten the locknut. Dimension "X" is the distance from the center of the eye in the rod end to the end of stem (5).e. Install larger retainers (4) on stem (5). Put spring (3) on the stem over retainers (4). Put the spring under compression, and install retainers (2) to hold the spring in place. Put clean oil on the valve stem.f. Install stem (5) in the valve body as shown. Put plate (1) in position on the valve body to hold the stem in place, and install the two bolts that hold it in place. Tighten the bolts to a torque of 25 5 N m (18 4 lb.ft.).2. Disassemble and assemble the overspeed valve spool as follows:a. Remove plug (10), spring (9), spool (8) and piston (7) from the valve body.b. Loosen the locknut on adjusting screw (12), and remove adjusting screw (12), washer (11) and the seal from plug (10).c. Install washer (11) and the seal on adjusting screw (12). Install the adjusting screw in plug (10).d. Put clean oil on piston (7) and valve spool (8). Install piston (7) in valve spool (8). Install valve spool (8) and spring (9) in the valve body. Install the seal on plug (10), and install the plug in the valve body