Correct Clutch?
 

My 67 GMC clutch arm clip broke so I needed to pull the Bell housing and realized the clutch was bad as well. So I wanted to pull it apart before ordering a clutch. So today I got it apart and someone had a 12" clutch in it ..

When looking up parts it shows 10" or 11" clutch.. it's only a 6 cylinder so I'm thinking 11"


What is the correct size ?

Re: Correct Clutch?
 

Post a picture of the throwout bearing and the face of your flywheel....

:chevy::chevy::chevy:

Re: Correct Clutch?
 

Here's my flywheel and throw out bearing..

Re: Correct Clutch?
 

Measure the diameter on the face of the pressure plate, that will give you the dimension. If all else fails, take the 3 parts (disk, pressure plate, TO bearing) to the parts house for matching.. Remove the flywheel and have it refaced.. It's an operation that's part of the job.

Re: Correct Clutch?
 

Measure the diameter of the clutch disk, that looks like a 11" but a tape measure across its face will verify.

Have the flywheel refaced and replace the bronze bush in the end of the crank. It looks like it has walked out a little.

Watch installing the clutch lever, make sure you add a little grease on the pivot. Also make sure the pivot ball is not worn out.

Finally, check the mounts for the transmission and replace if they are soft...it looks like there is some oil leakage in that area so check it out.

:chevy::chevy::chevy:

Re: Correct Clutch?
 

I planned on resurfacing the flywheel, the clutch measures roughly 11 3/4".

Re: Correct Clutch?
 

it looks as if only the outer 1 1/2" of the clutch disc was touching. I run a 12" heavy duty clutch in my 69 suburban with no issues, I went with the larger diameter since its a 3/4 ton 4x4. definitely have the flywheel turned, looks like it has hot spots.

Re: Correct Clutch?
 

I'm guessing here as to the style clutch you have, but I've seen diaphragm pressure plates warp and "cup" from overheating.. Usually caused by excessively slipping the clutch for whatever reasons.. Under any event, the abnormal wear pattern on the disk is caused from a "cup" shaped pressure plate.

It's already been stated by the posters here, but due to the importance, I'll say it again.. Reface the flywheel....

Re: Correct Clutch?
 

Thanks for the responses. I already planned on the resurfacing of the flywheel.

This is the pressure plate that was in it.

To save opening another post. Does anyone have a recommendation for gear lube transmission is to use GL-4 and it's no longer available from what I see and what I read I should not use GL-5. Because of the yellow metals in my transmission..

Re: Correct Clutch?
 

I just bought a quart of GL-4 Valvoline at my local Car Quest..

https://67-72chevytrucks.com/vboard/...1&d=1707179839


Others that are commonly available:

https://67-72chevytrucks.com/vboard/...1&d=1707175840

https://www.amsoil.com/medias/mtgqt-...E3MzQxMmI1NGFj

Re: Correct Clutch?
 

The bushing came out in my fingers and it not right at all in the crankshaft..

Re: Correct Clutch?
 

I guess I need to look around a little better

Re: Correct Clutch?
 

Picked up a new pilot bushing went in tight like its supposed to. Dropping off the flywheel tomorrow for resurfacing.

Re: Correct Clutch?
 

Looking at the clutch plate wear and the loose bronze bush in the crank, I would be very carefully checking out the front bearing on the trans input shaft.

Grab the end that goes into the crank and try and move it up and down across the face of the trans.....that front bearing may be ready to collapse....

Also triple check the engine and trans mounts and the pivot ball and bushes on the clutch pivot Z link.

:chevy::chevy::chevy:

Re: Correct Clutch?
 

Looks like a 12'' clutch. They measure at 11-3/4 to 11-7/8''. You can put on that flywheel what ever you want really. I'd stick with 11 or 12. Clutch wear is running on the outside edge because the last person to install a clutch in it did not have the flywheel surfaced

Re: Correct Clutch?
 

So I went to my local AutoZone and they had pennzoils syncromesh, I picked up a couple of quarts. The bottle says GL-3 is this sufficient?

Re: Correct Clutch?
 

GL-3 is fine....

GL-4 and GL-5 should not be used where yellow metal (synchro rings) are being used by the transmission....

:chevy::chevy::chevy: