Clutch going bad?

[Woodie1]

We have a Model A that is giving the following symptom. It runs fine on the flat roads but when climbing a hill, it sounds like the engine is racing. I'm thinking that the clutch disc is either getting worn or oil has gotten on it. In the event it is oil, I'm wondering what people think about taking the inspection cover off the clutch housing & spray brake cleaner or carb cleaner on the assembly to wash away the oil. Has any one done this & did it work for them? This engine was put in as a rebuilt touring engine 3 years ago. It did give a lot of blow by until I changed the oil fill tube out for one off an engine that didn't have a blow by problem.

[WHN]

When the engine was installed three years ago, what did the clutch look like?

Have you checked the adjustment?

When your going up the hill. If you add gas, does the engine rev up but the car doesn’t respond in its speed as fast as the engine?

[Kurt in NJ]

Is there free play in the movement of the clutch pedal?

[Woodie1]

The clutch has some free play. It is a lightened flywheel with V8 pressure plate. The clutch was all assembled when I got the engine back. I was told it was all new parts. When I go up hill if I give it more gas the speed may increase but the free wheeling gets worse. I don't want to make it worse so I will back off the gas a little going up hill.

[J Franklin]

Sounds like it is worn out or out of adjustment. Oil would usually make it grab.

[nkaminar]

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Adjust the clutch so that there is at least 1 inch free play. If that does not fix the problem you will have to take the clutch out.

[Woodie1]

I would have thought oil would make it slip.

[jw hash]

one other thing to look at is the rear wheel, you could have sheared the key. when it starts slipping watch the speedometer. if it speeds up it is not your clutch.

[Synchro909]

Originally Posted by Woodie1

I would have thought oil would make it slip.

A common incorrect assumption. It took me a while to get my head around that!

[Woodie1]

I sure hope it's not a broken axle. We drove over 200 miles Saturday with it doing this.

[ronn]

really does sound like your clutch just needs adjustment.

[Ramman]

If it's the clutch, I would think you could take off in 2nd, get it rolling maybe 5 mph and shift to 3rd and go full throttle. If it lugs and pulls the car up to 30 mph like that, stop and do the same test, then once in 3rd, push the clutch in about 2" then right back out. Only at 1/2 throttle. You'll know if it's the clutch or not.

[katy]

Originally Posted by Woodie1

I would have thought oil would make it slip.

Originally Posted by Synchro909

A common incorrect assumption. It took me a while to get my head around that!

That's strange.

I once had a '55 w/a 272 V-8, the rear main seal started leaking and oil got on the clutch, doing 30 or so (MPH), if I stepped on the gas the engine would rev up but no increase in speed.

[Woodie1]

At least At this time I don't have a broken axle. Checked that a few hours ago. I do have a few thousands end play in the driver side rear wheel. It may be a worn axle shim. I did pull the inspection cover off & I know I have a free throw out bearing. If I push the clutch in 3/4" the bearing starts to contact the pressure plate.

[Woodie1]

Ramman, I tried what you suggested & on the second time when I pushed the clutch in a couple of inches, the engine raced. I don't have anymore time to test today.

[johnneilson]

It sounds like the clutch cannot transmit full torque when you need to climb a hill
The V8 clutch has the centrifugal force weights on the arms and the tractor clutch doesn’t

In either case it is probably that the disk is worn below the preload height for the clutch assembly

I have dealt with this before
One answer is to have the disk relined with a thicker material
Or you can add shims under the clutch springs to increase preload pressure

Just be careful with disassembly of the PP
A hydraulic press is nice as you can lock the pressure as you remove fulcrum bolts then release slowly

J

[Woodie1]

I got to work on the clutch today. The old disc is .01 thicker than a new disc I have. I don't see any oil on the pressure plate or the disc. The throw out bear is shot. I will replace that as well as the pilot bearing.