K 3500 Truck 4WD V8-5.7L VIN R (1998)
4. Check the power steering pump belt for wear and improper tension.
5. Check the power steering pump pressure.
FUNCTIONAL TEST
1. With the ignition OFF, apply and release the brake pedal several times. This will empty the accumulator.
2. Apply and hold the brake pedal with 180 Nm (40 lb) of force.
3. Start the engine.
The pedal should fall away, and then push back against your foot.
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. Refer to Hydraulic Brake Booster
Replacement (Accumulator Overhaul) and Hydraulic Brake Booster Replacement (Check Valve Replacement).
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.
