Hydraulic Booster Seal Leak Diagnosis

INPUT ROD SEAL
A fluid leak from the inside of the driver's compartment at the power brake booster vent hole indicates a damaged input rod seal (5). Remove and disassemble the power brake booster. Check the input rod bore for any scratches that may cause the leak. If scratches are present, replace the housing cover. If no excessive scratches are present, replace all the seals using the power brake booster seal kit.

POWER PISTON SEAL
Fluid leaking between the brake master cylinder and the power brake booster indicates damage of the power piston seal (3). This can possibly reduce the power assist. Remove and disassemble the power brake booster. Check the piston for any scratches that may be the cause of the leak. If no scratches are present, replace all the seals using the power brake booster seal kit.

HOUSING SEAL
A fluid leak between the two housings indicates a damaged housing seal (6). Remove and disassemble the power brake booster. Replace the housing seal (6), input rod seal (5) and power piston seal (3) using the power brake booster seal kit.

SPOOL VALVE PLUG SEAL
Damage to the spool valve plug seal (2) causes fluid to leak past the accumulator cap. Replace the spool valve plug seal (2) with the power brake booster on the vehicle.

ACCUMULATOR SEAL
Damage to the accumulator seal (4) causes fluid to leak past the accumulator cap. Replace the accumulator seal (4) with the power brake booster on the vehicle.

RETURN PORT FITTING

NOTICE: Tighten the return port fitting (3) to 10 Nm (88 inch lbs.). Refer to Fastener NOTICE in Service Precautions.

If the leak continues, replace the seal ring under the return port fitting.