1986 GMC Safari Clutch won't release

MIKE 1

MEMBER
1986 GMC SAFARI
6 CYL
2WD
MANUAL
192,000 MILES

When clutch pedal fully depressed, engine is not disconnected from transmission (5 speed).

Pushrod moves out of slave cylinder about 0.5 inch instead of required 1 inch.

Replaced master and slave cylinders (new units) then bled line, many times - same result.

Clutch has about 12,000 mostly highway miles on it. External inspection through hole where clutch fork installed reveals lots of clutch pad remaining and area is very clean (no dust).

Clutch fork has considerable forward/backward play. If I apply gentle pressure on back of fork, pushrod will move back into slave cylinder about 1 inch.

Pressing on clutch pedal, no resistance for first two thirds of travel then resistance felt (point where pushrod starts moving fork).

Seems like all would be OK if pushrod was about a half inch longer.

Any help as to what may be the problem would be appreciated.

Thanks,
Mike

1 Reply

MIKE 1

MEMBER
3 POSTS

Problem solved!

Original work:
Replaced master and slave cylinders then bled system following instructions in GM service book - no change (clutch would not disengage and there was about 2 inches of pedal travel before any resistenace felt)

Subsequent work:
Bled slave cylinder by holding clutch pedal to floor then opened bleeder just enough for air and fluid to escape. Closed bleeder then slowly pumped clutch pedal until pressure built up. Did several times. (Slave cylinder bolted to vehicle)

Bled master cylinder the same way only loosened hydraulic pipe fitting slightly. Did several times.

Clutch worked, but just OK. Then noticed that master cylinder was not securely bolted to firewall. Once tightened, clutch worked OK