The GMC CCKW

My pressure plate is stuck to the fly wheel. Someone mentioned to me about taking a board and shoving it up against the clutch pedal and it might pop loose That did not work. Someone also told me to take a thin putty knife and slip it in between the clutch plate lightly tapping it, rotating the flywheel and going around the whole pressure plate. That did not work. Someone told me to loosen all of the bolts a little around the pressure plate cover and try the tapping again and that did not work. So I think I am ready for a new pressure plate, throwout bearing, etc.

Is there a new upgraded pressure plate, bearing, etc. and where do I find them?

Thank you. Steve

A typical failure of the CCKW clutch is that the diaphragm spring on the pressure plate breaks. When this happens you will have uneven force on the clutch plate, and the clutch will bind.

I have had two (2) "GMC Clutch" failures. In both cases, the diaphragm twisted and would not release. Both times it was caused by incorrect clutch pedal adjustment. You can over stress the spring easily and cause it to fail.

To adjust your clutch, make it disengage fully about 3/4" above the floor. The free play when the pedal is out, is what it is: When new, the pedal will have lots of free play. I can use the clutch with my heal on the floor. When the disc is worn out, you will have little or no free play.

Think about how the clutch works and what it needs to do: Engage and disengage. It is a sandwich of the flywheel, disc and pressure plate. You only need to apply the throw out bearing pushing against the spring enough to allow the disc to slip. Any more is overkill and will KILL the spring!

I have I think 5 CCKW manuals. Four of them are wrong.

Also, from my experience, do NOT have a clutch shop rebuild the pressure plate unless you supply a NOS spring. They put in one too heavy for the rest of the mechanism. I put it in and took it out. It is still hanging on the wall...

Start the truck in gear and drive it around...jerking it as much as possible.. then drive into a tree or bank of dirt, at a speed of something less than ten mph.....sounds crazy, i know...but this is a common failure with old trucks that have been sitting...this really works...once it breaks free it will work fine..trust me....I have done this twice and afterwards they drive just fine....gaining access to the pressure plate is a major fix...you can't just slip something between them, like a putty knife because there is a resess between them.
Gib

Sorry, I have to STRONGLY dis-agree with GibBuckbees suggestion. While it may work for some, it is an extremely destructive way to attempt a fix. If it were my truck that had this problem and had been out of service for some time, I would drop the transmission, pull the clutch, disc, and flywheel and take them into a big truck friction material shop and have everything rebuilt and resurfaced. It may be a BIG job to do, but it is "do-able" and is the correct procedure. Then your rebuilt assembly will last for at least another 35 years.
Crashing a vehicle into something to try to fix the clutch is like trying to remove the dust from Ming Dynasty Vase by hitting it with a ball peen hammer. There are some things that Ya' just don't do.