Diaphragm Clutch?

J

jeepguy1948

Well-known member
I just completed the installation of a new flywheel, pressure plate, and disc, all from Van Pelt. We went for a 10” clutch to try a soften it up (it’s in an ‘51 F-1 but since this truck will never haul more than a cooler and a couple lawn chairs so I consider it a car). Truck has the 3 speed light duty side shift truck (large bell, cast bellhousing) transmission. It chatters so bad the truck is un driveable. This is not the first clutch installation that I have ever done and I followed all the rules (clean, clean, clean). I checked flywheel run out as best I could. The 11” clutch that I removed chattered bad too which is why I replaced it. The linkage is as good as I can figure out how to make it so (most of the linkage parts are unavailable and used ones wouldn’t gain me anything. I am aware that as the clutch is engaged the movement of the motor causes the linkage to change which can create an oscillating chatter but if that’s the problem, I don’t know what to do about it. I’m thinking of going with a diaphragm clutch (I know that there are at least 2 different ones that have been used for this after drilling the flywheel) I’m open to suggestions.
 
Have you checked your motor/transmission mounts? That is the first place I'd be looking . . .

I can't see a new clutch solving the issue - as it probably had nothing to do with the new setup.
 
New motor mounts front and rear. I forgot to include that in my original post. Also, although it now has a duplicate of the original 3 speed in it, it had the original before the clutch/flywheel swap.
 
How tight do the front mounts need to be before the cotter pin is installed in the castelated nut? Never seen a spec. and some rubber mounts are quite hard and others soft. Who sells a proper set?
 
This is instructions from Ford Repair Manual for Transmissions and Clutches… might help with your chatter

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Note: some pressure plates now being sold do NOT have adjustable 'fingers' . Have heard of these PPs fingers Not being even when installed. Who buys cores and rebuilds the original Ford PPs ?? Newc
 
Hey Newc, this is Don the guy you sold the transmisssion to. It leaks a bit but not too bad. My problem now is the clutch.
 
By all means buy the diaphragm, you won't be sorry. I bought a complete package (disc, PP and flywheel) from Centerforce for my 8BA.
A search of this board and others like it is filled with complaints of rebuilt Long/Borg and Beck finger clutches. Seems not many check the finger adjustment.
 
The fingers on the clutch PP I removed were adjustable, the ones on the new PP are NOT adjustable. They were off by about .010 so I used a flap disc and made them even (I realize that I will not be able to return but that was a risk I was willing to take). I tried it before I evened the fingers and it chartered so I tore it apart, leveled the fingers, re assembled it. Still chatters BADLY. I tore it apart again and here’s what I got (it gets a little complicated for me to know how to explain it but I’ll give it a try). Using a dial indicator I find that the flywheel is off by .008” measured from the highest to the lowest so I’m not sure if that is considered .004” runout, or .008”. I also find that when I lay a straight edge across the flywheel there is a difference of approx .007” between the inner disc/flywheel surface and the outer disc/flywheel surface (this is over a distance of approx 2”) is this normal? Stranger yet, looking at the clutch disc itself on the flywheel side, all the wear is in the inner 3/4” of the radius (again, the disc surface is approx 2”). What has me ballfled is that is the opposite of what I would expect based upon that .007” difference inside to outside. I have no idea if this is making any sense but I’m doing my best. I think that something is very wrong but I don’t know what. I have also heard that sometimes the little spring layer is missing that is supposed to be between the flywheel side of the disc and the PP side of the disc. I don’t see anything like that but I may not know what I’m looking at. FWIW the flywheel, disk, PP, and pilot bearing are all new from Van Pelt. These problems have occurred with 2 different (matching) 3 speed transmissions. The original, and one I just bought from Newc. Unfortunately I no longer have the original flywheel or clutch disk because the tile setter thought that he would help out by taking them to recycle. Gene, I have heard real good things about Centerforce clutches (in the Jeep world).
 
The flywheel is brand new from Van Pelt. I described what I found with the flywheel surface in my last post. It doesn’t seem right to me but I’m no expert. If it’s supposed to be perfectly flat, it’s not.
 
I see that a precise .295” spacer block is required for proper measurement of the PP. I just happen to have a couple of those laying around (I’m kidding)
 
Check the thickness of the clutch disc. Most of the new discs are slightly thinner than the original. That coupled with an improperly surfaced flywheel and the PP not adjusted could can cause the clutch to slip/chatter.
 
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I will check that FlatTop. Does anybody want to tell me what the origianal thickness was? I know that the new one looks pretty thin to me.
 
Gene1949 said:
By all means buy the diaphragm, you won't be sorry. I bought a complete package (disc, PP and flywheel) from Centerforce for my 8BA.
A search of this board and others like it is filled with complaints of rebuilt Long/Borg and Beck finger clutches. Seems not many check the finger adjustment.
Click to expand...

Second this. I've very happy with the Centerforce clutch and pressure plate set up. I have it attached to a Weber aluminum flywheel. Works great.
 
When clutch chatter made my '49 undriveable, it was the throw out bearing assembly. Another Barn member had mismatched arm and hub that caused severe chatter. Might be worth checking.

This is what I found.
 

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