Clutch Adjustment?

[Jman]

Hey guys, When I rebuilt the motor in my 66 AH sprite I installed a new clutch, throwout bearing and pressure plate. The throwout bearing is not going far enough forward to fully engage the pressure plate. I was wondering if there is an adjustment on the pressure plate for this? I am getting about 5/8" of travel on the slave cylinder, but I don't think it matters. The fork is bottoming out against the bell housing before it engages the pressure plate. This leads me to believe that the pressure plate should be adjusted to engage earlier. Any thoughts on this would be greatly appreciated.

Thanks
Jeremy

 

[mxp01]

Jeremy:

I have a 1960 AH Sprite that has a later (1100) engine and even later transmission. There are slight differences in length on the pushrods on the clutch forks to slave cylinders, plus there is a slight differences in the position (mounted on the trans) and/or size of the slave cylinders in different years. Knowing exactly what engine/transmission combo helps a great deal.

To my knowledge there is no adjustment that can be made. I eventually used a socket from my wrench set to put over the end of the pushrod to give me the travel necessary to get the clutch to disengage - and it has worked great ever since.

Mike Pennell

 

[Jman]

I'm pretty sure its all stock stuff. The slave cylinder and pushrod won't make any difference because the clutch fork and throwout bearing is not going forward enough or the pressure plate isn't coming far enough back. Like I said before, The fork is hitting the bell housing before it engages the pressure plate enough to release the clutch. Thanks though.

Is it common for the fork to get bent? Mine looks pretty straight, but I'm not sure how it's supposed to look.

 

[aeronca65t]

Hmmm?

Hydraulic clutch fully bled?

Throwout bearing (#3) isn't installed backwards, is it? (see picture below)

Correct size bolt (#7a) in throwout arm (not too sloppy)?

Pivot bushing in arm (#7) isn't missing?

All I can think of is to look inside the bell housing with a mirror (if possible) and see if all looks OK.

 

[PeterC]

There are a few factors involved.
1) yes.. the fork could be bent. I've seen it.
2) Did you do any mixing of engine back plates and flywheels?
If you rebuilt the engine and replaced the original clutch with MATCHING parts, the the problem could be the bent fork, or much worse, missing thrust washers on the crank?

FYI the distance from the center of the release bearing peg to the face of the bearings is 948... 1/2"
1098...3/4"
1275.. .970"
If you changed backing plates from stamped to cast, etc. you need this info. If you used a 1275 flywheel on a 1098, you need to know that.

Before I go into all of the possibilities, did you use all original stuff?


Peter

 

[Jman]

As far as I know its all original. I bought the combo pack with all three pieces from Vic. British. It looked just like what came out of the car. How would I know if the thrust washers are missing from the crank?

Jeremy

 

[jlaird]

I found the problem, hehe, same that I have but not as bad.

The combo throwout bearing is thiner, like 1/4 inch than the orginal( I measured and installed it anyway, DUH . At least it was in mine from Moss. I will know even more next I pull the engine this fall when the weather is cooler.

 

[Jman]

So maybe order a new throwout bearing? Mine measured roughly 3/4" from the center of the peg to the face of the bearing like Peter said. I looked at the fork and it doesn't appear to be straight. I'm going to pull it and see. Was it supposed to be straight like it appears in the detail above?

Thanks for all the replies!
Jeremy

 

[jvandyke]

I found the problem, hehe, same that I have but not as bad.

The combo throwout bearing is thiner, like 1/4 inch than the orginal( I measured and installed it anyway, DUH . At least it was in mine from Moss. I will know even more next I pull the engine this fall when the weather is cooler.

Maybe this is what caused all my clutch adjustment issues as well. A non spec throw out bearing? How is it something that important gets through? 1/4" off is alot, no? I'd imagine this caused my Midget's gearbox to have issues since it was rebuilt long long ago. Resulting in my, the new owner to resort to the "nut behind the slave pushrod" trick. (goes well with the "nut connecting the steering wheel to the seat")

 

[jlaird]

No clue as to what throwout bearing deapth is supose to be. Just know that mine was 1/4 inch skinny. Has to cause a throw prob. At removal time will check the fork but I expect it is prob ok.

 

[Jman]

Alright guys here's where it stands now. I pulled the fork and from what I could tell it was definitely bent. I heated it and straightened it. Doing this gained me about 1/4". Now here's my question. Is there any way to get the original specs on the throwout bearing depth? Mine is 3/4" like I said before, but an inch or 1-1/4" would be perfect.

Would the bearing from a 1275 work? That would give me an inch according to Peter.

Jeremy

 

[PeterC]

As far as I know its all original. I bought the combo pack with all three pieces from Vic. British. It looked just like what came out of the car. How would I know if the thrust washers are missing from the crank?

Jeremy

I hope this isn't the case for you. It is way more common in Triumphs like Spitfires and TR6s. Thrust washers are on the crankshaft and provide a bearing surface for the forward and rearward thrust of the crankshaft. Forward thrust is most often when the clutch is depressed/engaged, the crank is forced forward against the washers. The test is with engine OFF, lever the crank rearwards by prying a large bar between pulley and steering rack. Then have a lovely helper depress the clutch pedal and observe if the crankshaft moves forward. It shouldn't be visible, and should be barely measurable. If you can see it move, there's a problem. It can happen on the A series engines, but is far more prevalent on the Triumph powered 1500 Midgets.

I would check the clutch fork and hope it is that. Perhaps someone can send a picture for you. I thought I could, but can't find the file.

Good luck. Peter C.

 

[PeterC]

Alright guys here's where it stands now. I pulled the fork and from what I could tell it was definitely bent. I heated it and straightened it. Doing this gained me about 1/4". Now here's my question. Is there any way to get the original specs on the throwout bearing depth? Mine is 3/4" like I said before, but an inch or 1-1/4" would be perfect.

Would the bearing from a 1275 work? That would give me an inch according to Peter.

Jeremy

I posted the original specs earlier. The 1275 bearing DOES fit the 1098 fork. You might consider a new fork. Moss shows them 190-955. Not cheap, but at the very least maybe compare. Bending it the second time, as you've done, can be problematic.

Peter

 

[Jman]

Thanks man, I'll probably get both the fork and the 1275 bearing just to be sure. Thanks for the info everyone.

Jeremy