Excessive Clutch Travel Mystery almost solved...

[maddmaxx1949]

Hey all, In my '49 basket case thread I had asked about and had been having some trouble with my clutch pedal travel really far before getting any engagement. I was checking everything, linkage, springs, forks, bellhousing measurements, anything I could think of. Since I had the lower bellhousing off I could see my clutch disk and I wasnt getting very much separation, basically none. All this at the last inch of travel basically on the floor. I snuck my head underneath and noticed that my pressure plate levers were being constantly depressed creating a large amount of travel for the throwout bearing before it engaged. Not quite sure on the exact cause of this yet, but this is for sure why my engagement was so late. You can see the depressed levers in the photos below. If you have seen this before, comment below, in the meantime I'm going to be checking the clutch disk construction, possible interference from another part etc. This is not pressure plate exclusive, I've had two different ones on and two fluid drive units as well.

[Dodgeb4ya]

Is the clutch disc too thick?

[maddmaxx1949]

It is the same thickness as the old one I pulled out, the only difference is the center build is modern. There is a comparison photo here.
https://p15-d24.com/topic/55913-clutch-disk-center-distance/?tab=comments#comment-600867

 

Protruding side goes towards the trans correct?

 

Edited July 23, 2021 by maddmaxx1949

[maddmaxx1949]

40 minutes ago, Dodgeb4ya said:

Is the clutch disc too thick?

You might be onto something there. The manual states it should be .125 inches thick and im at about double that. Plus if I back it off an approx. 1/8" the levers are just about where they ought to be. 

[maddmaxx1949]

I'm not sure what its supposed to look like to be honest. I lack the experience. Sometimes these things make it seem like I'm an idiot the other half the time its like I almost know what I'm doing. 

[maddmaxx1949]

Okay so I had a spare fluid unit and pulled the clutch disk and pressure plate to compare to one I pulled from the 51, assuming it was in driving condition at one point. Here is the difference. and what the fingers look like. The disks look almost identical in terms of thickness but maybe not so much because When I bolt down the pressure plate I get a noticeable amount of lever travel on the new disc. Measurements in picture for comparison. Any sage advice on what I should see would be appreciated. Picture on the left is old disk, picture on right is new disk.

 

[Dodgeb4ya]

Your disc thickness looks normal to me.

A disc too thick will cause the clutch cover levers to pull inward too far.

The correct new clutch disc lining...

Takes two as you mentioned .125".

New MoPar FD disc's are .325" thick.

 

[Dodgeb4ya]

It is normal for the fingers to pull in maybe 3/8"...on a good clutch disc that's not worn thin when tightening the clutch pressure plate.

Your release bearing after adjusting the length of the clutch fork rod should almost be right up against the three clutch cover fingers.

I think your disc and cover are probably OK.

.......Have you messed with the over center spring turn buckle?

......Adjusted the clutch fork rod (lengthened it to move the bearing up to the fingers) leaving 1/2" to 1"  free play at the top of beginning pedal movement?

 

[maddmaxx1949]

Okay thank you, Then that looks normal to me as far as depth for the new disk.

My release bearing has a good 1" at least of travel before it contacts the fingers. This is with the adjustment rod taken to where its just about to fall off and I checked the overcenter spring adjustment and worked its way from all the way in to most of the way out with very little change. The sleeve length matches to my other fluid drive car so I don't think it's that either. It has me stumped and frustrated...

 

I should add that my adjustment rod matches the length on my 51 and 50 and so does the rod the connects the pivot arm to the pedal.

I have at least 4-6 inches of free play.

Edited July 24, 2021 by maddmaxx1949

[kencombs]

Is the throwout bearing carrier original to that clutch housing and lever?  There are more than one of those over the long life of the flathead drive train and they vary in length.  When I was figuring out what I needed for my Frankentrans/clutch/housing I discovered I had 5 different ones in the shop.  Not even sure where they all came from.

[maddmaxx1949]

Yes it came with the car which included the the bellhousing and fork. It also matches the length of the '51 fluid Drive sleeve in length and is fairly long compared to the other truck ones and non-fluid drive carriers I have.  I'll get a measurement tomorrow and am going to drop the lower bellhousing on the 50 chrysler and see if there is any difference in length/ pressure plate depth etc. I will also double check the distance from the clutch fork ball to the pivot arm. That's kind of the only other thing I can think of is maybe the whole engine and trans can be moved up a 1/2" or so, but I find that as unlikely since its bolted in.

[Dodgeb4ya]

I believe it's improper linkage assembly or parts.

[maddmaxx1949]

I'll put the set together from the '51 parts so at least the fluid drive, clutch disc and Pressure plate and throwout bearing all match. I can also take the linkage and pivot arm from the 51 as well. That at least gives me a baseline of similar parts. I don't remember how the clutch felt on it before I took it apart but I don't remember anything bad about like this one.

[maddmaxx1949]

Okay so here's what I'm working with. The painted parts came attached to my '49 when I bought it. The rusty linkage I pulled from the '51 I had.

Throwout sleeve matches the one pulled from the 51 as well. Linkage all measures the same. Pressure plates are the same model B&B 952. Distance from clutch pedal lever to ball on frame is the same. I'll keep measuring things until I find something. Overcenter spring distance I'll adjust at the end as it doesn't affect the travel distance.

[maddmaxx1949]

Well to be honest fellas, this is still a bit of a mystery but I can only speculate at this point. I had removed all the linkage to compare and I assembled it all back together this time excluding the transmission so I could see where everything was. I installed the pressure plate and the old disk and just guesstimated the alignment just for a mock up. installed the clutch fork and made sure the throwout bearing was on properly. Viola, now I am right up against the pressure plate and actually had to back off my free play adjustment a decent bit. No clue what the difference was. Maybe the clutch fork was only on one side of the bearing sleeve? Not over the ball on the bellhousing properly? All I know now is that the pedal feels like a normal pedal. I'll check the disk clearance when I get a helper but it will be plenty. If it changes after I install the transmission (which should make no difference whatsoever) then I might have another problem. One of those head scratchers...

[maddmaxx1949]

Well with the pressure plate completely bolted down and transmission installed, I was able to take up most the play in the clutch pedal with the adjustment. I have about an inch and a half maybe 3/4" of free play and could probably get it down some more but I am not comfortable taking the adjustment out anymore.It is likely the linkage is worn a decent bit and definitely has a little slop so I am attributing the lack of remaining adjustment to the worn linkage. I have some but like I said not much so I dont want to unthread the rod accidentally.  I am curious to see how much play I'd have with the new disc ( I imagine I'd have a decent bit more maybe 2- 2-1/2" in but no way I'm taking the trans and pressure plate off again just to see.

[squirebill]

This could be a shot in the dark but it is easy to do.  I had an excessive free play on the clutch of my '49 B1B  truck.  Free play was almost down to the floor board. After going through a lot of what you are doing, on a recommendation by someone on this forum, I measured the thickness of the flywheel.  Turns out it was thin by 0.2 inches.   If I remember correctly it was 1.1 inches thick and a new one is something like 1.3 inches thick.  I had already sent my clutch assembly to Randall at Tennessee Clutch.  I called Randell  and the remedy was for him  to adjust the clutch fingers 0.2 inches from the normal specification.  I recommend you measure the thickness of you flywheel and compare to thickness of a new one.  Your car thickness may be different than my truck thickness.  Flywheels are often machined to true them up for various reasons which reduces their thickness.  As I said, could be a shot in the dark but an easy measurement to take. Regards