……
Corvair DiagramCorvair Photo
Corvair Center
home forum corvairs calendar links Corvair Podcast
California Corvairs
Clarks Corvair
Clarks Corvair
“CORSA"



Chevy Corvair License Plate
Chevy Corvair Chrome Wheel
Corvair Center Forum :  Corvair Center Phorum - presented by CORSA The fastest message board... ever.
Corvair Center 
Pages: 12Next
Current Page: 1 of 2
not your typical clutch won't disengage story
Posted by: engr1962 ()
Date: March 11, 2017 02:50PM

Hello all,

In December, I dropped #5 intake valve seat in my Rampside. Several hundred dollars later from my favorite machine shop, I have all new seats, guides valves springs, etc. I had a few oil leaks to take care of so while she was out, I replaced push rod tube gaskets and the real main seal was leaking and got oil on the clutch, so I replaced that too.

I replaced the clutch disc and put it all back together. Back in the truck, started right up, but won't go into gear. booooo

A couple years ago, I converted it from a 3 speed to a 4 speed. At the same time I replaced my rattly fly wheel with a new one from CA corvairs, along with a heavy duty clutch disc and pressure plate, pilot bushing, etc.

At this point in time, I had to pull the clutch cable as tight as I could get it to get it to disengage.

Now, all the same setup, but new disc, and I cannot get it to disengage, no matter how tight I pull the cable.

I hung my head and after reading many articles, figured I did the worst and put the disc in backwards since it isn't marked. Well, that was not to be. That would be too easy!

I am pretty stuck now as to what I am doing wrong.

The pilot bushing is installed 1/8" into the flywheel.

The one thing I don't have is a press to test the pressure plate to see if it releases.

Any other ideas? What can I measure or test to get answer?

Thanks to all

dan

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: MattNall ()
Date: March 11, 2017 02:59PM

What's the thickness of the Disc? Many of the newer units are too thick...

Re: Can't get it into gear 4 speed.
Posted by: steve c goodman
Date: May 02, 2010 07:02PM

One other thing comes to mind but unfortunately like my other suggestions above it is too late now that the powertrain is together. I always measure the thickness of the disc, typical is .310-.319". If the disc is thicker than that there is the risk of a no release situation. Sometimes overadjusting the clutch will work for a bit, take the free play out of the pedal and after some use on the street the disc gets worn a bit and then a readjust will make it right.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: steve c goodman ()
Date: March 11, 2017 03:36PM

Dan I have stated the following before and I always do it here at the shop: on the bench bolt flywheel/disc/cover together as on the engine
then in my press I push fingers down 7/8" and check if disc moves. If tight there is either a mismatch of parts or wrong dimensions on disc thickness or poor cover. If disc moves and still no release in car you have control issues.

Make certain the release brng matches flywheel/cover too. Good luck

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC/V8 Registry

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: cnicol ()
Date: March 11, 2017 06:50PM

One thing to consider outside of the more likely issue with the disc and pressure plate... the clutch cable. FC cables usually fail because the outside housing weakens and some of the cable motion is lost to expansion of the outer housing.

You can spot this as a sort-of squirming of the housing while the pedal is being pushed down. Not *real* likely but a possibility and one that I've seen a couple of times.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: BobV66Vair ()
Date: March 11, 2017 09:20PM

Most cars allow one to remove an inspection plate from the bell housing and see the pressure plate and disc. Then a friend can depress the clutch all the way to the floor while you check for the pressure plate freeing the disc. Some even allow you to put a feller gage between the disc and pressure plate. If you can see that happen and it still stays engaged, the plate is probably in backwards or the flywheel bolts have a head that is too tall. My recollection is that they have a low head. Putting the disc in backwards is another way to cause problems but you can usually hear the clatter when that happens.

Sad to say but when you reach the end of all the troubleshooting in the car, it has to come out. Have Steve help you once it's out.

66RTVair
Oregon
1965 Corsa 140 stock
1966 Monza DP Racecar
1968 Monza Parts for now

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: Tom Turbo ()
Date: March 12, 2017 08:13AM

Is it possible the cable is stretching? It sounds like a little stretch could be a problem.

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: Wagon Master ()
Date: March 12, 2017 10:24AM

Tom Turbo Wrote:
-------------------------------------------------------
> Is it possible the cable is stretching? It sounds
> like a little stretch could be a problem.


If the inner cable is stretching that much on each application, it won't be a issue too long. It'll snap. Problem solved.

Friends Don't Let Friends Drive Stock
Been Aircooled Since 1973
Northwest Ohio 45840

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: cnicol ()
Date: March 12, 2017 10:41AM

I have never seen an FC clutch inner cable failure. I have seen several FC clutch cable outer housing failures. (Same symptoms)

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: Timothy Shortle ()
Date: March 12, 2017 12:15PM

Dan, you may not want to hear this but it is still true. You will have it apart faster than your first time. Also, (not for Steve G. to read) I prefer PGs.
As far as far as "I don't have a press" an awful lot of auto repair shops/old time auto parts stores/machine shops do have a press. I have inexpensively let others use my shop press. If they were working on THEIR Corvair there would not be a fee.
Where are you at?

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: engr1962 ()
Date: March 12, 2017 03:05PM

You're right, Tim, it was out easily and apart. I took off the transmission and dropped the pressure plate and flywheel.

I reassembled the 3 on the bench, and went out and got an inexpensive press, I needed one anyway. It does release when I push far enough on the fingers.

Took it all part and the disc measures 0.355" ! I bought it from California Corvairs, for spyders, trucks and vans. If what I read above is true of 0.310", this one is way over, or I have the wrong pressure plate.

Ideas? smiling smiley

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: MattNall ()
Date: March 12, 2017 03:49PM

Way over.... Jeff's guys missed that... let him know!! They may have a bad batch..

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: not your typical clutch won't disengage story ; more info
Posted by: engr1962 ()
Date: March 12, 2017 04:43PM

When I put the combination on the press, I didn't really measure the depth. If I pump it down to 1/2" it releases nicely, if I go to 3/4" it binds up. At 3/4" the throw out bearing is being jammed onto the hub of the clutch disc and shoves the disc back against the fly wheel. Seems like I had too much throw on my clutch linkage, and I just instinctively pushed the pedal all the way down.

Funny how you assume more travel is better!

Should the bearing straddle the hub of the clutch disc and not bind or do I just need to pull back the linkage so it stops at 1/2"?

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: Frank DuVal ()
Date: March 12, 2017 09:00PM

Does this new disc have the welded center, or the riveted center?

I'm wondering, because the original welded center discs have "FLYWHEEL SIDE" stamped into the metal. Sure, after a few sandblasting cleanings for relining, it gets harder to read, but it is there.

I have had the riveted centers hang on the flywheel to crankshaft bolts. I will NEVER use another one!

So, to do this test right, with the press, one would also need to place the flywheel to crankshaft bolts in place to make sure they clear. Then I would not have had to R&R the brand new clutch disc I had put in....

You should not have the wrong pressure plate or flywheel, as they DID work!

Frank DuVal

Fredericksburg, VA

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: corventure Dave ()
Date: March 13, 2017 08:29AM

Can you verify that the clutch disk was indeed installed correctly? One side should say 'flywheel side".
The symptom you described originally is a classic one of having the clutch disk installed backwards. The clutch will hardly disengage or not engage if the disk is installed backwards. It's easy to overlook.

Corventyure Dave

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: engr1962 ()
Date: March 13, 2017 08:50PM

Here are a couple pictures of my clutch/throw out bearing and pressure plate combination.

The clutch disc is showing the pressure plate side.

I bolted together the pressure plate/clutch to the flywheel. I measure about 1/2" from the top of the hub to the top of the fingers on the pressure plate.

The hub diameter measures about 1.42" and the inside of the throw out bearing measures 1.37".

Thus the bearing binds on the hub when it travels more than 1/2".

Wrong throw out bearing?

Attachments:


Options: ReplyQuote
Re: not your typical clutch won't disengage story -Updates
Posted by: engr1962 ()
Date: March 26, 2017 11:04AM

Hi All,
I am still battling this one. I went ahead and got a new welded clutch disc from Clark's and it is oh, right on .310". I _can_ get this one to disengage, but to do so, I have to tighten ALL the slack out of the clutch cable so that the throw out bearing is hugging the pressure plate. This can't be a good idea, I don't think.

If I measure the cable travel at the transmission mount unloaded it moves about .8" loaded it only moves about .5" Seems like there is some loss someplace. What are the places you have seen? Cable stretch? Bending brackets? I am having trouble figure out where the .3" travel loss is.

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: MattNall ()
Date: March 26, 2017 11:22AM

Did you check the clutch cable's HOUSING as Steve G. suggested?

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: cnicol ()
Date: March 26, 2017 11:22AM

Did you read my early comments about the clutch cable housings weakening, expanding a little under pressure and causing lost motion? I've seen this several times over the years.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: Denisschoen ()
Date: September 25, 2022 08:23AM

Was this ever figured out ? I seem to be having the same problem .I did install a new clutch cable after reading this topic . Didn't make a difference. My combination is a 64 110hp FC block , using a PP and FW from a 65 180 turbo engine with new Clarks disc , bolted to a 64 diff and 64 4spd. Cable adjusted so TO bearing is touching PP fingers . When cold it allows shifting gears but when it warms up it can't be shifted into gear. ????

1962 Rampside 140 4SPD 3.55
1961 Greenbrier 110 PG 3.27
Northern California

Options: ReplyQuote
Re: not your typical clutch won't disengage story
Posted by: RobertC ()
Date: September 25, 2022 09:50AM

Denisschoen Wrote:
-------------------------------------------------------
> Cable adjusted so TO bearing is touching PP fingers .

Feeble memory does not think this is the correct adjustment.

As stated above, the issue may be a clutch disc that is too thick.

Options: ReplyQuote
Pages: 12Next
Current Page: 1 of 2


Sorry, only registered users may post in this forum.
This forum powered by Phorum.