HELP!!! Clutch won't disengage on 83 after engine drop (long)

[ischmitz]

I can't believe this GRRRRRRRR!!!! After putting MikeZ's powertrain back into the car I thought we we all done. It fired right up. He broke 2nd gear and we did some R&R to the 3.6. See here for details. However, now the stupid clutch won't disengage. I don't know what I did wrong. Here is where I am at:

When I put the transmission back onto the engine I made sure the clutch release fork went into the groove of the throughout bearing. I have done this many times before. We are talking about a '83 915 with the helper spring mechanism. I double-checked that the clutch fork was in there by peeking through the cutouts of the bell housing. The splined shaft that actuates the clutch fork felt fine, too.

Next we put the entire package into the car, hooked everything up, put oil in and fired her up. It sputtered a little bit (air in the fuel lines) and then it came to life and pured like a kitten. Great, at least the engine didn't hand-grenade.....

Next, I put the helper spring mechanism onto the transmission and tightned the clutch cable to the transmission housing. Then I put the smaller lever onto the splined shaft and adjusted the 13mm hexagon screw to have about 1mm gap. The clutch pedal feels great (stiff, almost no play) and it actuates the lever just fine. I double-checked that once you start pressing the clutch pedal you get action on the throwout lever being pushed by the adjustment screw. Tavel looks ample. However, with the engine running the clutch won't disengage. We have the car on axle stands. Once I put it into first gear the weels start to spin. When I press the clutch and then engage the E-brake it stalls the engine.

WTF, I am stomped. The only thing short of dropping the engine again is to get a mirror and see if I can get a visual on the throwout bearing through the upper cutout of the bellhousing with the engine in the car. BTW, we didn't even have the clutch off the pressure plate.

Any other ideas out there???

Ingo

[MotoSook]

Have you tried to readjust the cable tension? Sometimes the sheathing doesn't seat into the tunnel port until you actuate the clutch...then you 'll have more slack...

[ischmitz]

I watched the lever getting actuated just fine while Mike pressed the clutch pedal. I checked the workshop manual. It says you you should be able to measure about 29mm of travel of the arm. I will take calipers to the cable tomorrow and verify. But it looked fine.

I am beginning to think it could be the bearing in the flywheel...

[MotoSook]

Bearing in the flywheel? Do you mean TOB assembly in the pressure plate and shims/washers? They are so thin I have a hard time thinking they are preventing full throw.

Sounds strange...I would check the clutch cable and lever arm again. Have Mike pull up on th eclutch lever while you push the sheathing into the tunnel port and then adjust the tension at the lever.

If the fork is on the TOB, and the TOB is moving with the fork, it has to be cable related.

Of course since we're dealing with a 3.6 on a 915, the flywheel, clutch disk and PP arrangement may be slightly different than I expect. Yet's all mechanical, so if the TOB moves, so should the disk

[ischmitz]

Regarding the cable we already tried this: Mike ever so slightly started pressing the clutch pedal while I was watching the lever under the car. Once he started to press the lever started to move. And it kept moving while he pushed the pedal to the floor. The two adjustment nuts for the cable tension are roughly in the same positon they where in before the drop. I can see the clean parts of the thread on the metal guide tube of the cable. So that looks all good, too.

But to be absolutely sure I will measure the throw distance of the release lever according to the WSM tomorrow. But as I said; it looks normal.

I am 99.9999% sure the fork is on the TOB. I hope I can get a mirror so I can see the TOB moving when Mike presses the clutch tomorrow to be 100% sure. The fact that I can't rotate the splined shaft with the small lever by hand in either direction kind of seems to confirm this. Even a cresent wrench does not give me enough leverage to turn shaft with the short lever. But the lever rotates the shaft fine when the clutch cable is hooked up to the larger lever acting on the smaller one.

I was thinking about the pilot bearing in the flywheel being frozen. I did not have the pressure plate off the flywheel at all. So there can't be any fault in assembly. But what if the little bugger is for some reason frozen.....

Is there any waty that the clutch disk somehow got "bonded" to the pressure plate or to the flywheel? I am lost.....

[ischmitz]

OK, I am heading over to Mike again and I found Wayne's 101 projects. 25mm is what I am looking for in terms of travel. Let's see. More later....

[MotoSook]

I find it difficult to believe that the pilot bearing would create enough of a hold on the shaft to stall the car.

Take the helper spring out of the picture. You really don't need it, the tried to rotate the lever..still same resistance?

Very strange

[Joe Bob]

Still having problems....any ideas, please call 805-259-7332....at least tell us a joke or something....%^B

[Joe Bob]

Well...we figure the clutch disc is hanging on the shaft....gonna drop the drive train and lube the bastard.....

[MotoSook]

Sorry Mike. I'd recommend taking the clutch package apart and inspect the parts too, esp. the splines on the clutch disk.

[Early_S_Man]

Well ... a lot of the traditional explanations are dependent upon a long hibernation time under humid conditions, and this isn't the case, at least not the long time part:

1. Dryer venting into the garage ... flywheel and clutch disk bonded by rust ...

2. Humid storage conditions, i.e., coastline/lakefront garage ... same result as above.

3. Pilot bearing dry of all lube and rusted/bonded to input shaft.

4. Input shaft rusted/bonded to clutch disk splines ...

Could be a combination of two or more of the above ... none individually bad enough to cause the problem, but, when you combine the friction forces ...

[Joe Bob]

it's out...less than an hour....

[Joe Bob]

Disc was stuck to flywheel....

[Early_S_Man]

La Nina strikes ... maybe?

[Joe Bob]

Dunno....been hot AND DRY.

Engine is in....connecting stuff now...

[ischmitz]

A couple of images say more than a 1000 words.....







It seems like there is lots of activated metal in that clutch disk and on the friction surfaces. Given that brake disks haze over within 10 minutes when you wash a car it's no surprise that this clutch disk froze to the flywheel and to the pressure plate. I took some steel wool to the flywheel and the pressure plate and used a razor blade to make sure no surface imperfections where left. After putting everything back together it's alive and the clutch felt good. Not grabby or strange at all. I learned my lesson: Always take the pressure plate off after washing an engine with water involved.

Thanks again to Souk and Dave@TRE for listening patiently to my rumblings on a Sunday and to Dan for coming over and helping on the record engine drop. 55 minutes from taking a wrench to it to having it sitting next to the car. What's left to do. There is a tiny oil leak from the drivers side chain tensioner cover. The mating surface of the little cover is slightly bend. Oh well, it could be worse.

Cheers,
Ingo

[MotoSook]

You guys are like a 3-man army of ants!

Congrats!

[ischmitz]

Ha, that's funny. We almost felt like a pit crew while NASCAR was up on the TV in Mike's garage.

BTW, after we talked I had it in 3rd reving the engine with both wheels on and in the air. I stabbed the throttle about 30 times and reved the thing up to 5.5k with the clutch depressed. Nada. Tach and speedo were moving in union while the entire engine tranny package twisted noticable in the body from all the inertia of the two 9 inch wheels. That 3.6 would have most likely snapped the input shaft if we had tried something more radical like pulling the e-brake at speed. And I didn't feel like going through the 915 again.

[MotoSook]

I wish I was there to supervise while testing the California beer

Ya..better to have spent the time to pull it than have to track down another shaft....now go grab a beer!

[sammyg2]

My guess is that the clutch plate is stuck to the flywheel for some reason.
You'll proly have to pull it back apart, clean it up, and try again.

No no, don't mention it, I'm just glad I could help