clutch issue

[installman57]

Hi. I've got a 77 620 KC with a 5 speed trans. A while back the clutch disc dropped a spring. I didn't have the cash for a new clutch kit, so I put in a disc from another kit that I had. The disc is very good with little wear. It was replaced due to a pressure plate issue. What's happening is that when I first start the truck, everything is fine. After it warms up, the clutch won't disengage fully. It seemed like a hydraulic problem, so I replaced the slave and the flex hose. The problem is still there. Do I need to swap the master also, or do I need to save and do a whole clutch kit? Thanks in advance for your help.

[datzenmike]

Easy stuff first... Push down on the clutch peddle with your fingers. You will be pushing against a spring but there should be about 1/16" of slack before there is firm resistance. More than this and you are wasting peddle travel that could be used for moving the clutch. Next, check the tranny oil level. Now bleed the system at the slave.

[installman57]

Easy stuff first... Push down on the clutch peddle with your fingers. You will be pushing against a spring but there should be about 1/16" of slack before there is firm resistance. More than this and you are wasting peddle travel that could be used for moving the clutch. Next, check the tranny oil level. Now bleed the system at the slave.

 

 

Just bled the system and the adjustment is fine. I fabbed an adjustable actuator rod for the slave and that is good. The piston is almost bottomed out with the clutch disengaged. Also I drained and refilled the trans with new oil when I swapped the clutch.

[datzenmike]

OK

 

When cold measure the distance the slave pushrod moves and compare it to the distance when warm. If the same, there is nothing you can do from the outside and the problem may be inside.

[installman57]

OK

 

When cold measure the distance the slave pushrod moves and compare it to the distance when warm. If the same, there is nothing you can do from the outside and the problem may be inside.

 

 

Thanks. I will try that when the motor cools down. I might just replace the master anyway. It is about 6 years old and they are pretty cheap.

[installman57]

Thanks. I will try that when the motor cools down. I might just replace the master anyway. It is about 6 years old and they are pretty cheap.

 

Decided to just forget it and replaced the clutch, throwout and put in a nissan roller pilot bearing. Everything work fine now. On to brakes and bodywork.