C 2500 Truck 2WD V6-262 4.3L VIN Z (1992)
Vacuum Brake Booster: Symptom Related Diagnostic Procedures
Accumulator Leak-Down, System Does Not Hold Charge
1.
Contamination in steering hydro-boost system.
2.
Internal leakage in accumulator system.
Grabby Brakes or Booster Chatters/Pedal Vibrates
1.
Faulty spool action caused by contamination in system.
2.
Power steering pump belts slip.
3.
Low fluid level in power steering pump.
4.
Faulty spool operation caused by contamination in system.
Slow Brake Pedal Return
1.
Excessive seal friction in booster.
2.
Faulty spool action.
3.
Restriction in return line from booster to pump reservoir.
4.
Damaged input rod end.
Brakes Grab
1.
Faulty control valve.
2.
Broken or damaged hydraulic brake lines.
3.
Faulty master cylinder seals.
4.
Cracked master cylinder casting.
5.
Air in hydraulic system.
Hard Pedal
1.
Internal vacuum leak.
2.
Faulty control valve.
3.
Broken or damaged hydraulic brake lines.
4.
Collapsed or damaged vacuum hose.
5.
Plugged or loose vacuum fitting.
6.
Bad stud welds on front or rear housing on power head.
7.
Faulty booster diaphragm.
8.
Restricted air filter element.
9.
Worn or distorted reaction plate or levers.
10.
Cracked or broken power pistons or retainers.
Slow or No Release
1.
Faulty pushrod adjustment.
2.
Binding linkage.
3.
Blocked passage in power piston.
4.
Air valve sticking shut.
5.
Broken piston return spring or air valve spring.
