Clutch Slip

[BobbyG]

Guys, Went for a little drive and after about 12 miles my clutch started to slip.

When in top gear if I hit the gas too quick the engine starts to race without a whole lot else happening.

1937 V8 with 37 3 spd box - can someone tell me how to adjust clutch or point me to a info source please.

I am hoping it is just an adjustment but knowing my luck it will be engine & trans out.

Thanks

Bob

[V8COOPMAN]

If there's any freeplay in the pedal, I don't believe your optimistic (adjustment) idea is gonna pan-out. DD

[FlatheadTed]

Remove the cotter pin from the clutch arm ,then screw in the clevis until your pedal has play against the floor board .

[ford3]

clutch pedal should have at least 1 to 1 1/2 " free play when depressed down with your fingers

[BobbyG]

My pedal sits at the point where there is zero free play when pushing it down, however if I pull the pedal up from this sitting position there is about 3" of play before it gets resistance.

I know nothing about this clutch/box system - all help appreciated

[Mart]

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Bobby, there should be a spring pulling the pedal up. It will rest on the underside of the floorboard. There should be free play from this position before it picks up the slack in the linkage and starts to release the clutch.

Mart.

[BobbyG]

Mart - no spring on mine but if there was ( and there will be just as soon as I can find one suitable) there would be about 3" of slack before the pedal starts to do anything when pushing down.

Can someone advise how to adjust it please

[Mart]

Fit a spring so the pedal comes up against the underside of the floorboard. You could fit some rubber bumpers under the floorboard so those flattened areas of the pedal arms contact the bumpers when the pedals are "up".
That threaded clevis is where you do the adjustment. Undo one end and loosen the locknut. Turn the clevis end until the correct amount of pedal free play is achieved. around 1-1/2" at the pedal pad has been quoted above. Refit the clevis pin, nip up the locknut and carry onski.

[V8COOPMAN]

Originally Posted by BobbyG

Mart - no spring on mine but if there was ( and there will be just as soon as I can find one suitable) there would be about 3" of slack before the pedal starts to do anything when pushing down.

Can someone advise how to adjust it please

With 3" of pedal free play, my dumb bet would be that your clutch hat (pressure plate), at the least, has some broken springs within, as I was alluding to in my first post. If so, that won't "adjust-out". DD

[BobbyG]

Fitted a spring - adjusted push rod - test drive seemed ok not slipping yet - Very Happy

Going to put some more miles in over the weekend.

Thanks all for your help on this very much appreciated

Bob

[Vic Piano]

Good for you Bob. Funny how some guys always look for the worst case scenario before suggesting doing any troubleshooting to solve a problem.

[Bluebell]

Bobby G, What you might have learned is that as your clutch wears, the "free board" (The slack bit of pedal travel) becomes less and less.
When you have used up all of the free board, the thrust bearing starts loading up on the fingers of the pressure plate, just the same as if you were already pushing on the clutch pedal.
With the Ford type pressure plate the fingers have weights on them which tend to throw out (with engine revs) This has an added clamping effect on the clutch plate,but would not happen if you had run out of clearance.
By re setting the clutch free board you have now let this clamping effect happen.
You might notice the free board is different at idle than it is when you have the revs on.
You may well have completely solved your trouble.
I hope that helps to give you some understanding.

[Ross F-1]

I can't see how reducing from 3" of free play to 1-1/2" would improve a slipping clutch?! Surely the weight of the pedal (because of the missing spring) wouldn't cause slip?

[V8COOPMAN]

Originally Posted by Ross F-1

I can't see how reducing from 3" of free play to 1-1/2" would improve a slipping clutch?! Surely the weight of the pedal (because of the missing spring) wouldn't cause slip?

I'd be open-minded enough to have someone (maybe Vic can troubleshoot what I overlooked) explain that to me, too. Always open to learning. DD

[Vic Piano]

I'd like to help you Coopman but I'm too busy out driving our cars & trucks.

[Old Henry]

Bob, Here's the spring you're missing to pull your pedal back up to the floor: http://macsautoparts.com/campaign_pr...S0R3CHL1072420

It's # 7523 in this diagram. I hooks around the knob on the passenger end of the rear clevis pin. I can see that knob in your picture bare naked of the spring.

[Bluebell]

Ross, V8 Coopman, Is this directed at me?
I read BobbyG's first post, and the one where he indicated it was fixed. I made the mistake of assuming he had no freeboard left. (the normal fault) I'd missed the 3" travel bit. (I read it all before but not recalled all the detail. Maybe that bolt in the bottom clevis was binding enough, that with the weight of the pedal (and no return spring ) it was enough to let the clutch slip?
I don't know, but something has changed. I was just trying to give BobbyG some understanding of how it worked.
BTW BobbyG, that shouldn't be a bolt in that clevis. It should have a clevis pin.

[Ross F-1]

General comment, not directed at you in particular. Maybe I'm missing something, but I can't see how anything is really changed that would eliminate slipping. I wonder if water/antifreeze got on the disc, and has dried out?

[Old Henry]

Originally Posted by Bluebell

BTW BobbyG, that shouldn't be a bolt in that clevis. It should have a clevis pin.

Good call Bluebell. You were more observant than I. I missed that one.
The pin is 5/16" X 31/32". The cotter pin 1/8" X 5/8".
Sorry I couldn't find a source.

[Old Henry]

Originally Posted by Ross F-1

General comment, not directed at you in particular. Maybe I'm missing something, but I can't see how anything is really changed that would eliminate slipping. I wonder if water/antifreeze got on the disc, and has dried out?

Originally Posted by Ross F-1

I can't see how reducing from 3" of free play to 1-1/2" would improve a slipping clutch?! Surely the weight of the pedal (because of the missing spring) wouldn't cause slip?

Originally Posted by V8COOPMAN

With 3" of pedal free play, my dumb bet would be that your clutch hat (pressure plate), at the least, has some broken springs within, as I was alluding to in my first post. If so, that won't "adjust-out". DD

In theory, I agree with all of you.
But this may just be one of those times, that often happens to me, when I take something apart to find out what's wrong, can't find anything wrong, put it back together and it's fixed!
Sometimes just any change will do, no matter how illogical. I just happens.

Let's hope Bob is so lucky.

[BobbyG]

Thanks Henry - diagram helps a lot - I am going to replace that bolt with a pin this weekend.
I do have a better understanding of how it all goes together now, and on a short ( 5 mile) drive it was not slipping, it does appear that the weight of the clutch pedal was pushing the release bearing inwards to make contact, I was thinking that maybe I was also making it worse possibly by riding the clutch a bit as well - this V8 is in a 28 coupe and there is not a lot of room for my size 13s in there !! - and driving this car is a bit of a new experience for me ( usually laying underneath it with parts spread all around trying to work out what the hell I am doing ) so as a consequence I find myself having a lot to do when driving it. For a start it is a Left Hand Drive Stick but the gears are in the wrong position! and I am in the Uk ( Good fun - but a bit challenging) I am listening out for mechanical noises constantly and to be fair I don't have a lot of success on getting back home under my own steam so far.

I appreciate everyones help as allways - Thankyou Guys.

Bob

[JM 35 Sedan]

"Left hand drive stick but the gears are in the wrong position"

Bob, that's how we feel driving there.... wrong side of the car, gears in the wrong position and on the wrong side of the road . On several trips to the UK we rented large motorhomes. Now that got really scary on those one lane country roads!
How are the water pumps doing?

[V8COOPMAN]

Originally Posted by Bluebell

Ross, V8 Coopman, Is this directed at me?
I read BobbyG's first post, and the one where he indicated it was fixed. I made the mistake of assuming he had no freeboard left. (the normal fault) I'd missed the 3" travel bit. (I read it all before but not recalled all the detail. Maybe that bolt in the bottom clevis was binding enough, that with the weight of the pedal (and no return spring ) it was enough to let the clutch slip?
I don't know, but something has changed. I was just trying to give BobbyG some understanding of how it worked.
BTW BobbyG, that shouldn't be a bolt in that clevis. It should have a clevis pin.

Bluebell...NOT directed toward you in any fashion. You obviously have a good grip on the physics of how a mechanical clutch and it's attendant operating linkages are designed to work. I'm only TRYING to imply that IF the pedal is 3" from the toeboard, and that ALL the linkages are still in place, that the clutch is already in a state of diminishing clamping force. I've lost more than one pressure plate in the past 45+ years, and more than one of those happened without prior warning, as I've (maybe mistakenly) ASSUMED that this one has. One big indicator is that all of a sudden, it'll slip in high gear, and the pedal "free play" has SUDDENLY become excessive (3" in this case). DD

[Bluebell]

V8Coopman, fair enough. My experience is general rather than flathead v8 specific. I'm here to learn, to help, and to have the odd laugh. Thanks for the comment in the other thread. Cheers.

[CT AV8]

I also do not understand how the free play adjustment has any effect on the amount of clutch engagement, but I am open to learning something new. The clevis rod, I thought, was adjusted to set the clutch pedal level with the brake pedal. As the clutch disc wears, you take up the additional travel with the threaded rod. I can see how if adjusted too short, it would not permit complete disengagement when depressed, resulting in gear grinding when shifting. But when the clutch release lever is in its rear most position, the clutch disc/pp should be fully clamped, unless they are completely worn or have picked up some fluid.
Am I seeing this wrong?

[Terry,OH]

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I did not see your brake pedal return spring either. Take the photo below with a grain of salt, it is not mine. This is clutch pedal return. Clutch spring is 78-7523 is 2.81" OAL, Brake is 78-2456

[BobbyG]

Originally Posted by JM 35 Sedan

"Left hand drive stick but the gears are in the wrong position"

Bob, that's how we feel driving there.... wrong side of the car, gears in the wrong position and on the wrong side of the road . On several trips to the UK we rented large motorhomes. Now that got really scary on those one lane country roads!
How are the water pumps doing?

Water pumps are spot on John - good as gold - I put the 4lb valve on the overflow as well and not lost a drop - Skip Haney pumps are the business.



Sitting on the left is not too bad for me I have had a lot of 'left hookers' but most have been auto trans as is my 55 Chevy - so it is the gear changing using my right hand that is a bit odd to me ---- getting used to it now and I have stopped trying to pull away forwards by selecting reverse !!

Bob