Clutch won't disengage

We ran into a mystery while replacing the clutch assembly on Leftcoast65's van. Now, when you push the clutch pedal to the floor, the clutch is not fully disengaged. Grinding gears. The new throwout bearing was longer than the one we took out.

Discussion going on here:

https://vintage-vans.forumotion.com/t39210p225-dons-day#215705

Thanks.

Throwout bering in backwards?

The clutch kit is usually a matched set. In that the presure plate fingers are designed in such a way that when installed with the correct thickness of clutch disc. The presure plate fingers will be standing in a calculated position. The throw out bearing is also designed to meet the fingers in the intended location/position on the transmisions input shaft sleeve. The suplied throw out bearing "seeming to be" too tight is "the problem" that needed to be looked into to figure out why in the first place.
Installing the shorter throw out bearing was a bandaid attemp at making the problem go away, and in doing so you created a different secondary problem. The problem now of the clutch not fully disengaging is clearly because the shorter throw out bearing is consuming too much of the availible clutch linkage travel. 1/2" is a hell of alot of linkage travel to be lost.
You need to get rid of the shorter throw out bearing and go back to assesing the suplied bearings and its appearant " tight fit". The suplied bearing may in fact now fit that you have driven and seated in the new clutch disc and plate.
Normally any clutch installation will seem tight untill it is all assembled and you then pump the cluth and/or run it to alow it to seat and settle into where everything needs to be sitting.
In fact after installing any new clutch assembly, you realyy need a good run around the block a couple times before adjusting the "free play".

M1D

the story is,,,,,,,,,LeftCoast65 decides to replace his clutch in VanAgains driveway and I drive down 50 miles to bring him some tools and parts for it,,,,,,,and I hand him the tools while he lays in a puddle of 90w while 30w drips down from the floor on him,,,,,,,so I am not getting too close to the operation,,,,,I leave after we put the trans back in,,,,,,,,and he finishes it up,,,,,VanAgain is at work,,,,,the major problem is that the new throw out bearing wont fit between the fork and the fingers,,,,the fingers seem too far out,,,,now, the disk did come out a few times to check the pilot bushing, it could of ended up being put in backwards,,,,,,but NO WAY the new bearing would go in,,,,and the old short one fit good,,,,so he put it back in to get back on the road,,,,,and now he says the clutch wont disengage,,,,,so I am wondering why that little bearing was in there in the 1st place,,,,,,,it surely is not the same as the long one that comes in the clutch kit,,,,and now nothing works,,,,,,at least he could drive his van with a slipping clutch before,,,,so it needs to come out and see what is wrong,,,,,,maybe that clutch fork ball is the wrong length,,,throwing off where the release bearing rides,,,,,maybe a bad disk or plate,,,,,,but its all about learning about keeping these vans going,,,,so lets see how this situation turns out,,,,,,,,,

here is an old clutch I put back together,,,,,the fingers are flat and the longer 2" bearing fits ,,,,,,I think his fingers were sticking up too high,,,,,,,,

Here is the old pressure plate bolted to the old flywheel, with the old clutch disc in between. It's 4" from the tips of the pressure plate fingers to the back of the flywheel. But the important measurement is from the tips to the surface that mates to the crankshaft. That's approx. 3.45".





No wonder it had that shorter throw out bearing, with those fingers sticking up so high.

Next, I'll see if I can peek at the clutch fork ball through the torn rubber boot.

when a disk wears,the fingers move out towards the release bearing and his disk is down to the rivets, so that will move the fingers outward, but the normal fingers sit about 1/2" down inside of the cover and use the longer bearing,,,,

...measure the disk thickness,,,,,,I would say a good disk is a little thicker than .300

Great photos, Don! That site you linked to shows the 1.5" and 2" balls.



I peeked in through the torn boot on the clutch fork opening and put a straight edge against the backside of the fork. Then I measured the distance from there to the back face of the bellhousing. About 1".

Don, would you check the one in your photo to see if that's what you get? When the fork is attached to the ball, is it about 1" from the hex-head-end to the back of the fork? Looks like you and Leftcoast have got the shorter of the two, wouldn't you say?



It seems to me that a longer ball might allow his short throwout bearing to push in further. But I'd rather find a way to allow the taller bearing that came with the kit to fit. You said the fit was so tight on that taller throwout bearing that it would have taken a hammer to get it in there.  Would changing the length of the ball help?

Now I'd like to compare your fork and his. That site shows pictures of a dozen different GM clutch forks (though none look cast like ours) and says this about them:



http://www.4speedconversions.com/gm-forks

And I double-checked, and there's no way the clutch disk could go in backwards. Not only would it collide with the crankshaft bolts, the springs on that side of the disk scrape even without the crank bolts there.

I would not rule out the disk being in backwards,,,,you can force anything and the plate fingers would absorb the springs even if they hit the flywheel bolts,,,,and that disk would be glued to the flywheel so it would never release,,,,,but the fingers are too high on his old and new plates,,,,see if you can measure his old disk,,,,needs to be at least .300....add washers or a shim to bring the thickness up if necessary,,,,,I want to know how much those fingers retract as you increase the disk thickness,,,,,and you could be right about the fork,,,,,,I think I need to bring more spare parts to see what works,,,,,,,

,,both my old clutches fingers sit about 1" from the disk,,,,,all my forks are the same,,,,he needs to also get a ball retainer clip,,,,,,and replace the pilot bushing whenever he gets back to work on his van,,,,,,

Well, the tranny has to come out no matter what. And then the bellhousing, to see what's going on in there. I sure wish these had an inspection cover on the bottom, like the automatics, so we could peek in there without taking everything off.

When you guys take it apart again, I will bring down a complete clutch set up and you can see what the differences are,,,,,,,

My clutch chatters a bit on slow starts and makes a ticking noise, I know it needs replacing and I am lining up a shop to do it soon, but any ideas what's causes the ticking sound? Finger hitting something? and should I worry about doing it sooner than later??

Do you have free play in the pedal,,,,,,,does the noise only happen with the clutch pedal down,,,,,when you step on the clutch the throw out bearings job is to  MOVE forward until it hits the fingers,,,,,now as a disk wears, it gets thinner and that makes the fingers move towards the bearing and makes it spin,,,,NOT GOOD,,,,,that wears it out,,,,so make sure you can pull backwards on the fork and that you feel the bearing move forward to touch the fingers,,,,,now the ticking could be the springs loose in the disk also,,,,,,I think things need to get a little  worst before anything bad happens,,,,,

Ticking sound- possibly one of the large springs inside the clutch plate is broken-ive had that before myself. can also be the pressure fingers hitting something? likely get it all replaced soon!! Ever seen anyone loose afoot or leg or 2 from an exploding clutch assembly??

a couple of other things about replacing the clutch is the flywheel may have cracks in it from heat,,,,you might be able to have it turned down and the pilot bearing that is pressed into the end of the crankshaft for the transmission shaft to fit in,   sometimes its hard to get out if it needs to be replaced,,,,,but people should be experts on clutches by the time this topic ends,,,,,,,

These are diaphram pressure plates,,,aint no springs in them,,,,,,HOWEVER,,,,he shouldnt be doing burn outs or wheelies until he gets the clutch changed,,,,,

All great info!  The free play is good and the ticking sound is heard at idle, goes away when the clutch is engaged and you hardly hear it while underway, but its there.  I remember when I first got the van, a mechanic told me it was probably one of the disc springs broken, loose or worn and hitting as it spins....I think I will visit a few shops sooner than later....hard to find a good shop anymore who is willing to work on vintage cars.  I may have found one nearby, there are always old muscle cars, Vettes and some 57's Chevy's there so I assume they could handle a van clutch, but I'm worried about dealing with the tranny hangar and radiator fan issue when dropping the trans down to remove it, hopefully I can find an old school mechanic who remembers how safely to do this withouit removing the radiator and/or fan first.  I have both shop manuals to show them, 63 truck and van supplement, but I'm sure I will get the "don't insult me" attitude when I offer the books for them to read the proper procedure...unfortunately, I don't have the facility or no-how to do this job myself and live too far from Donivan to bring it over for some help!.....

Doesn't this trick work, so you don't have to tilt the engine so much: Once the tranny hanger bolt is removed (and linkage and the other four tranny bolts removed), can't you rotate the transmission 90 degrees to get the hanger clear of the crossmember? Then you just pull the tranny straight out of the bellhousing?

that is true,,,,,,the further you lower the transmission, the closer the fan gets to the radiator,  so you need to watch what is happening,,,,,

I figured there was a trick to it without having to remove the radiator to do the clutch....I'll mention this and even show them the pics! Thanks!  Been saving my money to get this done by an experienced pro....

You are right to worry about strangers driving or working on our vans,,,,,they are different,,,,,they have their own set of rules,,,,,its better to be safe than sorry,,,,,,,we don't need people creating new problems when they try and fix old problems,,,,,