11" Clutch Problem

2

29Jethro

Junior Member
I have a 59ab with a '39 3 speed top loader. The flywheel is drilled out for a 11" pressure plate and clutch disk. When i press down on the clutch pedal i have about 1" of free play then the clutch disengages and works properly. If i press the clutch pedal all the way down the clutch engages again. Should there be a stop for the clutch pedal or release shaft? Any help would be appreciated.
 
Sounds like when you press the clutch to the floor the fingers are catching on the pressure plate. Adjust a little more free play into it. I wonder if there are some mis matched parts here like the collar the T.O bearing is on or if there is an arm on the shaft. Maybe wrong T.O. bearing (too thick)
 
I will look for these things tonight. There could be mis matched parts. This was with the RPU when i bought it. it was never working.
 
Jethro, not liking the sound of
The flywheel is drilled out for a 11" pressure plate and clutch disk
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I will relate a horror PIA occurrence using a flywheel originally manufactured for a particular pressure plate / clutch but modified for a larger combo as it seems you have. After installing a rebuilt 8BA engine & ‘39 ****** in my ‘35 all seemed ok up to 700-800 rpm while checking operation of clutch @ idle speeds. After satisfied all clearance & operation was fine I took it out for its maiden ride after refreshing the all the mechanics. I immediately noticed a vibration starting @ 1000 rpm & getting worse the more it revved. Unfortunately as all seemed fine with clutch operation I went on a search & find for 3 months checking the drive shaft balance, rims, engine pulleys, removed the engine twice checking to see if my crank had a bent flange @ flywheel. Finally had a friend on FB with a local shop look @ it. Having more experience than I he discovered the problem was the flywheel modification by someone obviously without machine shop experience had drilled & tapped the new flywheel mounting hole pattern for his chosen pressure plate size was .040”-.060”, not concentric. As FB friend indicated to me it’s a more common problem than you think. Hope your flywheel if redrilled & tapped for different pressure plate than original is correctly done on a precision turntable & Bridgeport.
 
There are no built in stops on the clutch arms except the cover itself. Your best bet is to put as much free play as it takes to have the clutch engage at a point near the floor. If it still acts like what you suggest, I think you need to pull the clutch out and see what is going on. Has the clutch pedal or any of the linkage been modified?
If you have the clutch out, get or borrow a magnetic dial indicator and check the holes where it had been drilled as AnthonyG described, they might not be concentric. If they are not, get another flywheel, and a 10" clutch. You don't need that 11" one. Especially if you have a light car. That 11 is for big trucks.
 
The pressure plate is a long finger type that has had the fingers shorten to fit around the gear box input shaft cover. Other than that everything is stock.
 
Jethro, Do yourself a BIG favor and use a 10 inch clutch and pressure plate.
You will have to have the flywheel redrilled very accurately and perhaps balanced.
 
19Fordy,
I have a new 9" clutch setup that i'm thinking about having the flywheel drilled and balanced. I have a very competent machine shop in town that can do it. Would a 9" be to small?
 
Reading over Rumbleseat's articles, he ran a 9inch in his "48" convertible with no problems. Drag raced it and even towed a trailer at times.
 
Not sure what actual combination of parts you have, but when you said the clutch fingers needed to be shortened, that was a bit odd to me? I've never had an issue with a flathead clutch where the clutch fingers needed to be shortened - so I don't know what actual pressure plate this combo started with (or the disc that is in it).

I see no reason to run a 11" clutch - unless you have a dump truck. There is not a single advantage to speak of - and a few downsides (like acceleration).

A 9" clutch (if correctly built) will handle the load of even a high-performance flathead, but I have no clue as to what 9" clutch/disc you have, its clamping force, etc. I'm always suspect when somebody has some parts laying around, that they're going to throw on another engine - who knows the specs on what they have? They may work, they may not . . . your gamble.

If it was mine, I'd be looking for a new flywheel and 10" clutch/disc setup - about as standard as it gets.
 
I believe Rumble seat ran heavier springs in his 9". I have a 9" with a flywheel with the blob weight trimmed off, stock PP springs and I can make it slip with a 59A with Merc crank, single carb, Merc cam. I like it though, it revs up fast. Need to get some stronger springs in there though
 
When you say "blob weight" trimmed off . . . are you talking about the weights on the outside of the clutch forks? If so, then you've lost the additional clamping force that these weights provided - which would contribute to your slippage issue.

As you noted, you can increase the static spring clamping force (heavier springs) to overcome the loss of the centrifugal clamping force that the PP originally came with.
 
The blob is the big weight around the 9" flywheels, about 40 or so on back. trim it flat in a lathe, and you take off about 12 pounds if I remember correctly. Lightest "Ford" flywheel you can get according to Rumble seat
 
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I think I understand what is going on with my clutch. The finger height and free play were not set correctly. The clutch fingers could be depressed so far that the fingers hit the spring on the clutch disc that it caused binding and the clutch to drag. It seems that the floor board is the "clutch pedal stop". I will play with it some more and If I don't feel comfortable, I will pull it had have the flywheel set up for a 9" clutch. Thank You everyone for all of your help and support!!!!!
 
cas3 said:
I believe Rumble seat ran heavier springs in his 9". I have a 9" with a flywheel with the blob weight trimmed off, stock PP springs and I can make it slip with a 59A with Merc crank, single carb, Merc cam. I like it though, it revs up fast. Need to get some stronger springs in there though
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Yes, he used 10 inch pressure plate springs. He stated he pretty much proved the 9 inch clutch will take the punishment.


I'm running a nine inch also with a lightened up flywheel. I don't have any slippage, with that said, my car is also very lite.
 
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1964-1972 Mustangs only have 10"and 10.5" clutches and they have way more horsepower than a flathead I can't see any reason to ever install a heavy 11" clutch on a flathead unless it is a heavy truck. And, I have never heard of somebody grinding away the clutch fingers. Get rid of that clutch and put in the correct one.
 
Are you sure you have the clutch plate in the correct way around. I did that on my first attempt. The proud side of the clutch plate should go towards the flywheel.
 
29Jethro said:
19Fordy,
I have a new 9" clutch setup that i'm thinking about having the flywheel drilled and balanced. I have a very competent machine shop in town that can do it. Would a 9" be to small?
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y

My 40 Coupe came new from the factory with a 9 in. clutch and the original owner drove it for 23 years with no problems. Then I bought it and drove it for 2 more years with no problems. The only reason I changed to a 10 in clutch and pressure plate was because I installed a 1950 Merc engine that came with the Merc. 10 in. clutch, pressure plate, flywheel. All I had to do was install those parts using the OEM 1940 throwout bearing . You will be just fine with the 9 in. clutch. There was no noticeable driving difference between the 9 and 10 in. clutch.

 
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