What are the mechanical limits to clutch freeplay?

[malpais]

I have an 8BA with an 11” clutch and ’39 transmission in a ’39 PU frame. Original pedal mechanism. Trying to understand he clutch operation – I’m probably missing the obvious. I want to make sure it’s correct before putting a new clutch from FWC and body parts on.

First, there seems to be no way to get a 4”adjustable push rod, as mentioned on some posts, in there, and have reasonable pedal position. The original rods were at 6” – I still have them for several 39 transmissions (out of several ’39 pickups) and they are rust-frozen at 6”. Any reason a pickup should be longer?

The clutch seems to work , but there is about ½” total travel of the TBO front to back before it hits the PP fingers, allowing the pedal to move (free play) over 6”. Pedal position is ok where the TBO hits the PP, but there is nothing stopping the pedal coming back. What should stop the pedal on the way back, toward the seat? Floorboard?

Thanks,

Gordon

[malpais]

I forgot to look at the Green Bible. 6" is correct for a commercial.

Thanks,

Gordon

[George/Maine]

There is one thing about 39s,to work correct,
you need the orginal 39 lever on the trans,and a spring return for pedal.

[jimvette59]

Originally Posted by George/Maine

There is one thing about 39s,to work correct,
you need the orginal 39 lever on the trans,and a spring return for pedal.

Can you show a picture and length of a 39 clutch leaver ?

[George/Maine]

I don,t have a picuture,from center to center about 3 1/2" goes off about 11 oclock and is in line with 39 pedals.
The pedals have a short throw little movemnent and when used with 4" lever grinds in gears with correct adjustment.
Shorter the lever the more throw. 39 is a one year arm.

[malpais]

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Jim,

This is the one that was on my 39 pickup.......it's roughly 4 1/4 inches center to center

[malpais]

The Green Bible (page 340) says 39-42 passenger and commercial both use the same arm - 91A 7511. Unfortunately, it doesn't give the dimensions.

[George/Maine]

I don,t know if the larger pickups are the same linkage.
If you have a 1/2 ton the lever is to long.
Could bend it is shape of S to make shorter.
Shorter more clutch movement.
Someone put a 32 trans in my 39 car, and thats how i know.

[malpais]

George, Thanks for all your help.

I'm going to have to do some diggin' in the parts piles. I'm pretty sure this 39 pu came with the arm that's on it, and according to your experience, that's too long.

I have a 3 1/2 arm that someone welded to the release shaft. Maybe I can grind that off and use it. Sure wish I could find the length of the 91A-7511 that the bible says is correct.

Too many of my tranny's no longer have release mechanisms!

I may post the original question again sometime: What stops the pedal on the return stroke? Maybe it's the floor pan.

Thanks again,
Gordon

[V8 Bob]

Originally Posted by malpais

...The clutch seems to work , but there is about ½” total travel of the TBO front to back before it hits the PP fingers, allowing the pedal to move (free play) over 6”. Pedal position is ok where the TBO hits the PP, but there is nothing stopping the pedal coming back. What should stop the pedal on the way back, toward the seat? Floorboard?
Thanks, Gordon

The floor is the pedal return stop, so the cab and floor have to be in place with the pedal fully spring returned before any clutch adjustment can be made. There only needs to be about a .100" clearance between the TOB and clutch fingers when FULLY released. This should give about 1"-1 1/2" pedal free play. Check to make sure the clutch does not exceed the manufacturer recommended maximum disc/plate clearance when the pedal is against the floor, usually around .040"-.060", depending on style. i.e., Long, B&B or diaphragm.

[malpais]

Bob, thanks for the reply.

You have answered my primary question - I just thought Henry would have something more substantial than the floor to stop the pedal on return. Shouldn't have taken this thing apart so many years ago.

I think a 38 pedal mechanism I have has a stop built in - at least it seems to hit the hub casting.

One question always leads to another though, and I'll have to figure out if the 4 1/4 in release arm I have is right. The green bible and folks' experience don't seem to agree.

Thanks much,

Gordon

[V8 Bob]

[QUOTE=malpais;554519]Bob, thanks for the reply.

You have answered my primary question - I just thought Henry would have something more substantial than the floor to stop the pedal on return.

Gordon,
All the V8 Ford cars and trucks I am familar with that have floor mounted pedals use a rubber pad on both the clutch and brake padal arms that prevent metal to metal contact as well as provide a seal to keep weather/fumes out of the interior. Suspended pedals in Ford '52-up cars and '57-up (?) trucks may or may not have some mechanical pedal stops.

[George/Maine]

If you have floor up the adj rod should be pretty straight forward.
The orginal lever is bent to keep in line.
Now from side to get max pedal,
up hitting floor after floor is back in place. 1/2 inch.
now when i hits pp should be about 1 oclock full pedal down about 11 oclock.
The 39 is a one year lever.Someone is making them new, they are hard to find.
If you have a 1/2 ton pu 11 inch clutch is to big. 9 or 10 ok.

[Karl Wolf]

If you'ld like, happy to measure my 39 Deluxe... Just not right this moment...
I would recomend cutting and welding to shorten an arm. I made a fake 1932 clutch arm from 3 different pieces, grinding sides to blend the parts... Came out real well.

Let me know on the measurement thing,
Karl

[malpais]

George,
Thanks again for taking the time to answer my questions. Hope I’m not making a mountain out of a mole hill. Started ‘cause I want to clamp something to the frame to simulate the floor, just to try things out. (Final adjustment will have to happen after the cab is on). Your pedal positions are real helpful. I guess if “touching the PP” is 1:00, the pedal in resting position, with floor in truck, must be 2:00 or 3:00?

I’ve found the transmission and linkage may or may not be the original, so the lever could be anything – probably explains why it’s too long.

I ordered a 95A-7511 lever from the Early Ford Store. That’s what the Green Bible says is correct for 39-42. If it’s not 3 1/2 “, I can start cutting and welding.

I realized at some point the 11” clutch is too big, so I found a 10” flywheel and have a 10” PP on the way from Fort Wayne clutch.

Thanks again, Gordon

[malpais]

Karl,

I'd appreciate that measurement when you get a chance. From the earlier posts, seems pretty sure it'll be 3 1/2 inches, but would be nice to know. No hurry. It's colder in Colorado than California, and my shop isn't heated, so have to wait for sunny days to work on stuff.
Thanks much,
Gordon

[barnfind08]

All these ford arms have the part number on them . your arm should have 91A-7511.

[malpais]

Barnfind,

Thanks for the info that they should have #'s. The one I started with doesn't have any (photo), but knowing they should be there allowed me to find them on some comparison arms.

Seems the one I started with is a 40-7511B (4-1/2"), same as a big truck tranny I have.

I found a 48-7511 (3-1/2") too, but it's welded to a shaft.

Interestingly, looking at these things, the pin bore is at different angles and would change the position of the arm......

I'll have it made when the 91A-7511 I ordered gets here.

Thanks, Gordon