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#1 |
Registered User
Join Date: Jun 2022
Location: Battle Creek Mi
Posts: 66
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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 ? |
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#2 |
Moderator
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Location: Cherryville, NC
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Re: Correct Clutch?
Post a picture of the throwout bearing and the face of your flywheel....
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Family and country before all others... 2006 Chevy Silverado (Daily Driver) 2012 Chevy Equinox ![]() ![]() ![]() |
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#3 |
Registered User
Join Date: Jun 2022
Location: Battle Creek Mi
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Re: Correct Clutch?
Here's my flywheel and throw out bearing..
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#4 |
Registered User
Join Date: Dec 2017
Location: Elkhart, Texas
Posts: 1,692
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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.
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#5 |
Moderator
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Location: Cherryville, NC
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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. ![]() ![]() ![]()
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#6 |
Registered User
Join Date: Jun 2022
Location: Battle Creek Mi
Posts: 66
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Re: Correct Clutch?
I planned on resurfacing the flywheel, the clutch measures roughly 11 3/4".
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#7 |
Born Psycho
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Location: brentwood,cal,usa
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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.
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jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA |
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#8 |
Registered User
Join Date: Dec 2017
Location: Elkhart, Texas
Posts: 1,692
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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.... |
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#9 |
Registered User
Join Date: Jun 2022
Location: Battle Creek Mi
Posts: 66
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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.. |
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#10 | |
All stock and staying that way
![]() Join Date: Jul 2003
Location: Elkland, PA
Posts: 1,456
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Others that are commonly available: ![]()
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1970 K/5 Blazer CST 4WD, Bronze, 93k ACT. miles, 350, 4 speed, positraction, 16.5" x 8.25" wheel option, tilt, tach, vacuum, AM/FM, manual throttle...Dad ordered and purchased new 4/70. Currently frame off restoration in progress... ![]() 1972 Cheyenne Super 20 2WD, DK Blue/White, 90K ACT. miles, 402, TH400, 4.10 open, tilt, tach, vacuum, A/C, AM/FM, manual throttle.. A mostly original paint never rusted Texas survivor... ![]() 2017 Sierra 1500 SLT 4WD, Black, 41k miles, 5.3, 6L80E, 3.42 LS, 20" polished wheels, everything but moonroof and 6.2... 2019 Canyon SLT 4WD, White, 60k miles, 3.6, 8L45, 3.23 LS, 18" wheels |
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#11 |
Registered User
Join Date: Jun 2022
Location: Battle Creek Mi
Posts: 66
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Re: Correct Clutch?
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#12 |
Registered User
Join Date: Jun 2022
Location: Battle Creek Mi
Posts: 66
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Re: Correct Clutch?
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#13 |
Registered User
Join Date: Jun 2022
Location: Battle Creek Mi
Posts: 66
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Re: Correct Clutch?
Picked up a new pilot bushing went in tight like its supposed to. Dropping off the flywheel tomorrow for resurfacing.
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#14 |
Moderator
![]() Join Date: Jun 2017
Location: Cherryville, NC
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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. ![]() ![]() ![]()
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#15 |
Senior Member
![]() Join Date: Mar 2003
Location: Colfax-California
Posts: 8,519
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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
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#16 |
Registered User
Join Date: Jun 2022
Location: Battle Creek Mi
Posts: 66
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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?
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#17 |
Moderator
![]() Join Date: Jun 2017
Location: Cherryville, NC
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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.... ![]() ![]() ![]()
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Family and country before all others... 2006 Chevy Silverado (Daily Driver) 2012 Chevy Equinox ![]() ![]() ![]() |
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