VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Unable to disengage clutch in 31

In previous posts I have described how I was having issues grinding gears when I attempted to put my 31 into gear. After replacing the transmission fluid with 600w gear oil, and adjusting my clutch pedal per repair manual specs I am still having the same issue. Finally I took off the bottom clutch housing cover and had someone turn the engine while the clutch pedal was fullying depressed. Interesting, the drive shaft is still turning even with the clutch fully depressed. So that explains the grinding... Any suggestions on what to look for when I take the clutch off?

Thanks,
John

Was the clutch replaced recently or has it been sitting for a long period of time? If replaced recently it's possible that the disc was not lined correctly or if the flywheel was turned it may have not been done so correctly. Also the release levers inside the clutch pressure plate could be worn or the surface they ride on worn reducing the release travel.

If the clutch plate is too thick, the throw-out carbon worn, pressure plate arms worn it may not release.

If the car has been stored for an extended period the clutch plate may be held by rust or corrosion. If that is the case start the car in gear and then press in on the clutch while alternating and braking. The stress may be enough to break it loose. Let it warm up well as heat can weaken the bond. If that does not do it then drive it to stress the system even more. Yes you can often start a warm engine with the transmission in first gear. Or push it in second gear to start it. I have done all of the above in the past 50 years.

Thanks for the suggestions, the are very helpful. They reminded my Dad that he never disassembled and restored the clutch. The clutch assembly is covered with rust which I thought was recent and pretty minor. It has probably been 50 years since the clutch has been disengaged.

My '28 had the same problem after sitting for over 40 years. I finally pulled the tranny (left the engine in the truck) and discovered the splines in the tranny drive shaft were rusted, thus preventing the clutch from disengaging.

Cleaned up the splines, put a dab of grease in the pilot bushing, put in a new clutch and newer-style throwout bearing, and been happily shifting ever since.

Cheers, Dean

I took apart my clutch and have not found any rust problems yet. I did find a couple of things that I am concerned about and want to get expert opinion. The issues are

A). The wrong clutch plate was installed in the car. A 10" versus the correct 9".

B). On the clutch throwout bearing sleeve there was some rather thick brazing on the collar. The collar is almost twice as thick as original. This looks like some form of repair that was done to the car before we bought it in 1975.

C). One of the cap screws that attached the pressure plate to the flywheel broke off. Do you think I can get by with just 7 cap screws or do I need to drill out the broken bolt and replace it?

D). The pressure plate assembly has clearly been restored including the presence of yellow clutch springs. Given that the car had a 1 1/2 ton truck clutch plate installed I am wondering if it has the correct clutch springs. The clutch springs look modern. I could not find any color code information online.

I am hoping to avoid taking apart the pressure plate assembly if possible. Do you think that issue (A) and (B) are the source of my disengagement issues, or do I need to keep looking? My throwout bearing does not appear to be original, but does look to be in good shape. So I don't that is the issue...

Thanks,
John

Here is a picture of the repaired clutch throwout bearing sleeve. Note the thick brazing on the collar.

[img]https://drive.google.com/file/d/0B-vMV_RPLv9ubzVNV0Y0R19tN2s/view?usp=sharing[/img]

I'm just guessing, but I suspect the thickness of that brazing is preventing the clutch sleeve from traveling far enough to actuate the clutch fingers, thus preventing the clutch from disengaging.

Since you have the whole thing apart, I suggest getting a new clutch throwout sleeve, a newer ball bearing type throwout bearing, and the correct clutch plate.

And, if it were me, I'd get that broken bolt out. I also suggest using new bolts to hold the pressure plate in place. That broken one might indicate that the others are weak too.

When I have something like the clutch assembly apart, I try to be as proactive as possible to prevent failures in the future. A few dollars spent now could prevent a future teardown.

All my best, Dean

When I tear mine down here in the next month or so I am replacing ANYTHIGN that looks SUSPECT. Not going to take any chances, take time and replace while i have it open. not wanting to open it again to fix later.

I redid my clutch last year, there is a new sleve out & the
thrust bearing is on the end of it. Where your is welded.
,it engages against the donut versas friction. It will cure future donut problems. Also you should replace the bolt holding the knuckle for the wishbone holding the carbon donut. mine broke so you need to put a stronger one in.
this bolt can be adjusted to engage your thrust bearing sooner.
make sure your thrust bearing is free when your clutch is out. just screw this bolt tighter until the thrust bearing is about 1/8"or so free
with the motor ideling. & clutch is out.
This is probably why your pressure plate don't release quick
enough when you push the clutch in.
Also I use wd 40 to clean the pressure clutch disk
while idling .

Remember when you reinstall your tranny to have it IN GEAR so you can twist it a little to line up the spleens, otherwise the spleens can float & not line up very good.
learned that the hard way.
Dulty

I talked to a fellow from Washington State, His dad died leaving a lot of old chev parts of the 20s to him, he said he could not find someone to give or sell to them so he sent 2 dumpsters full to the trash, too bad.
Dulty

One more thing, My 31 clutch pressure plate did not have springs in it. so yours with springs (cuts the chatter) the fingers hitting the springs may cause them to engage the disk too much, to cure that grind them where the springs hit a little so they are always free of the springs,
good luck
Dulty

The bolt that the wishbone shaft knuckle goes on can be adjusted from below by taking the clutch pan off. as time goes by , to engage or disengage the throwout bearing a little , to stop gear grinding or clutch slipping, This is good to know I think.
Dulty

Thanks for everyone's help. After replacing the clutch plate and the throw-out sleeve I can now disengage the clutch. The car is now one huge step closer to actually moving under its own power!

Did you get a sleeve with the thrust bearing milled on the end?
Dulty