K 2500 Truck 4WD V8-379 6.2L DSL (1989)
Vacuum Brake Booster: Testing and Inspection
Delco-Moraine Brake Boosters
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.