1. If normal pedal force and stroke develops braking pressure, but the pedal then drifts to the floor, service the head and barrel (13).
2. If the pedal will not return to normal height after brake application, service the spring case (20).
3. If brake fluid leaks past the shaft or the spring case, replace seals (8-12) and (23).
4. If the supply tank (3) appears defective, discard and replace complete assembly.

When servicing the assembly, always refer to the nameplate assembly number on top of the supply tank.

Note that only 1-1/2" and 1-3/4" diameter assemblies are now available. Two-inch diameter assemblies are no longer manufactured.

Temporarily block fluid supply from Fluid Reservoir/Bleeder and drain fluid from the supply tank (3). Remove four stud bolts and head and barrel assembly (13). Clamp barrel lightly in vise in vertical position with piston end up. Remove stop wire (19A), support ring (19), piston (18), cup retainer (17), return spring (16), and valve and valve seat (14). Clean cylinder using only brake fluid or isopropyl alcohol. Do not use gasoline, cleaning solvent or mineral oil. Bypass port holes must not be clogged. If cylinder bore is scratched or pitted, discard and replace head and barrel assembly.

Reassemble head and barrel in reverse order using all new parts (14, 16-19A) from Head and Barrel repair kit. Lubricate parts with 21B Brake Fluid. Clean residual fluid from supply tank reservoir and reinstall head and barrel using new head gasket (31). Make sure that piston push rod aligns with socket on lever (5).

If the pedal will not return to normal height, loosen the three screws (26) and apply 125-175 in-lb counterclockwise torque to the spring case (20). Tighten screws. If this does not help, the clock spring may be defective. Loosen screws and unwind the spring case clockwise, remove the screws and spring case. The spring case is serviced as a J17626 kit including items 20-26. Note that a new spring case includes a 1-1/4" hex for tightening with standard wrench. A J 73923 gasket kit is also available including only items 23-26.

To reassemble, lubricate gasket (23) with brake fluid and slide over spring case (20). Insert assembly into supply tank (3) while rotating to engage pin (21) to slot in shaft (4). Attach three lock washers, case washers and screws loosely. Use wrench to wind spring counterclockwise to 125-175 in-lb torque. Tighten the screws and check torque by installing pedal with pad 14-15" above floor. With head and barrel (13) in place, depressed pedal must return to original height.

Remove retainer, felt seal, snap ring, retainer plate and "O" ring. Use new parts (8-12) from J10799 shaft kit. Dip "O" ring and felt seal in brake fluid and reinstall in reverse order.