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-   -   Clutch not Disengaging (https://67-72chevytrucks.com/vboard/showthread.php?t=600118)

jhama78 10-12-2013 12:25 PM

Clutch not Disengaging
 
Long story short, I finally got my 67 delivered to my house and depressing the clutch pedal doesn't disengage the disc from the flywheel. About 4 months ago I had the same problem when I stopped by where my truck was stored. To fix it then all I did was start it in gear with my foot on the clutch and the disc evidently freed itself up. This time it hasn't worked. All linkage for shifters and clutch are working, the disc just doesn't seem to want to disengage.

Anybody had this problem before? Any ideas how to free this thing up so I don't have to drop the trans? I drove it down the road earlier and matched speeds to shift all the while the clutch was depressed, but it never disengaged.

Any help or suggestions would be appreciated. If it doesn't fix itself soon I'm gonna start yanking the trans out.

Cheers

-j-rod

Richardwa 10-12-2013 12:44 PM

Re: Clutch not Disengaging
 
sounds like clutch plate stuck to flywheel. I have got them to break loose by putting it in high gear, foot on the brake and just bumping the starter till it pops loose

72supermike 10-12-2013 12:49 PM

Re: Clutch not Disengaging
 
another possibility is that the clutch disc in in backwards. Did this one time and it would slip the clutch when fully depressed but not fully disengage. You could get it running and moving but it wasn't right.

geezer#99 10-12-2013 01:05 PM

Re: Clutch not Disengaging
 
Adjust the free play out of the clutch. THe long threaded rod between the zbar and the fork is where you make the adjustment. Loosen the lock nut and turn the rod until there is no free play on the tob on the disc. Once there, turn it back a couple turns to place the tob about 1/8 to 1/4 inch from the disc. Tighten the lock nut up again and it should be good.

jhama78 10-12-2013 01:59 PM

Re: Clutch not Disengaging
 
I definitely don't think the disc is in backwards, the drivetrain only has a few thousand miles on it since my grandad had it rebuilt in the early 90s. The truck has just been sitting more over the last year since he passed back in January. I drove the truck back in July and it was fine after the disc unstuck itself. I'm gonna try putting it in 3rd and bumping the starter with the clutch depressed and see if it frees itself up.

Backup plan is to see if I can get a brakleen straw in there some way to possibly give it a quick shot and dissolve some rust. Anybody see anything wrong with that as a plan B before I pull the trans?

cdowns 10-12-2013 02:09 PM

Re: Clutch not Disengaging
 
lack of use and the thing is stuck together by rust/// we used to just bump it into a tree to get them to break free

adjusting linkage will do nothing to help

jhama78 10-12-2013 02:25 PM

Re: Clutch not Disengaging
 
Yeah, the linkage and freeplay is fine, I checked that out last night. Hopefully I can get this thing squared away so I can drive it some this afternoon.

Thanks again gents for the input.

-j-rod

geezer#99 10-12-2013 02:36 PM

Re: Clutch not Disengaging
 
Quote:

Originally Posted by jhama78 (Post 6311240)

Backup plan is to see if I can get a brakleen straw in there some way to possibly give it a quick shot and dissolve some rust. Anybody see anything wrong with that as a plan B before I pull the trans?

If you want to pull the tranny and change out the disc then spray away with your brakekleen. Because you will be changing the clutch! Cause you never, ever get any petroleum based cleaners on the disc surface!!

fp1967 10-12-2013 03:19 PM

Re: Clutch not Disengaging
 
I've seen this a few times too. When it happened to me on a 4WD, I removed the cover from the bottom of the bellhousing. While somebody else was holding the clutch pedal down, I pounded a gasket scraper between the disc and the flywheel and pressure plate to break the rust loose. It's been so long since I worked on a 2WD with a standard that I don't know if you have the room to do this with the crossmember under the bellhousing.

jhama78 10-12-2013 03:36 PM

Re: Clutch not Disengaging
 
Quote:

Originally Posted by geezer#99 (Post 6311288)
If you want to pull the tranny and change out the disc then spray away with your brakekleen. Because you will be changing the clutch! Cause you never, ever get any petroleum based cleaners on the disc surface!!

Clutch disc material is similar to brake lining material isnt it? That's why I figured bpc would be OK. I've always cleaned every flywheel and pressure plate I've installed with parts cleaner to get the oil off of them prior to installation and haven't had a problem. Obviously I'm missing something in the composition of as clutch disc.

richard2717 10-12-2013 03:43 PM

Re: Clutch not Disengaging
 
I have sprayed my clutch plate,pressure plate and flywheel down on several occasions(with brake kleen) with no adverse effects back when I had a leaky rear main seal on the engine. Cleans things up fine. Don't know that it would help unstick the rust but shouldn't hurt it either.

hyatt 10-12-2013 03:52 PM

Re: Clutch not Disengaging
 
Start and drive it with pedal depressed accelerate and let off quickly a few times and it will come loose I have several antique cars and it is a common occurance

jhama78 10-12-2013 06:22 PM

Re: Clutch not Disengaging
 
Tried everything including driving it with clutch depressed. Ended up pulling the flywheel dust cover and slipping a putty knife in between the disc and flywheel to free it up while my bud held the clutch in.. Then drove about 25-30 miles this afternoon. All is good.:chevy:

oklalawnboy 10-12-2013 11:50 PM

Re: Clutch not Disengaging
 
I love a good ending to a story. Glad you got it free. Rust is never a friend.

Mr Handy 10-13-2013 08:24 AM

Re: Clutch not Disengaging
 
Quote:

Originally Posted by fp1967 (Post 6311333)
I've seen this a few times too. When it happened to me on a 4WD, I removed the cover from the bottom of the bellhousing. While somebody else was holding the clutch pedal down, I pounded a gasket scraper between the disc and the flywheel and pressure plate to break the rust loose. It's been so long since I worked on a 2WD with a standard that I don't know if you have the room to do this with the crossmember under the bellhousing.

This works, this had been happening to my buddy's c20. take the inspection plate off, have someone push the clutch in, or use something to depress the clutch. Climb under truck and use a thin putty knife to free the clutch plates from the fly wheel. Go for a drive with a working clutch.

Edit, great to here you got it working. It's pretty simple when you know what to do!


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