clutch release problems

[mini64]

So I switch out my clutch release bearing from the older flat face type to the still available round nose type, replacing the bearing carrier to match it and cutting out the platen on the pressure plate so the bearing rides directly on the fingers, all as instructed. System works good for maybe 50 shifts, but now the it feels like the clutch will not release, keeping me from putting it in gear. All seems from the outside to be moving fine, but I see the release ?fork? that the slave cylinder pushes against is moving so far that it hits the edge of the cutout in the bell housing, preventing it from going any further. Any ideas what is going on?

My only idea was that I did not adjust the slave pushrod after putting everything back together ? my slip up ? since you never have to take it off for this job I didn?t think to adjust it. So somehow this new round nose system is a different thickness and required a different starting position, and/or more throw, and I was pushing the fork up agasint the bell housing opening and slowly bending it until it was bent so much it wasn?t moving enough to release the clutch disc. Only now I have the engine out and can look at it better and I don?t see it obviously bent. And it seems to be riding on the ball pivot ok too. I don?t really know how close the fork got to the bell housing opening before, but normally there is that rubber gaiter in there too, which was squeezed out.

Could something else be drastically wrong ? I guess I need to pull the pressure plate and make sure the disc didn?t explode. Or could I have lunched my gearbox, itself kind of old, and the hitting fork is just a coincident problem from me not adjusting the pushrod. Also, I know my gearbox input shaft needs a new bearing as you can wiggle it a bit, so I suppose it could have seized in the crank pilot bearing since that bearing would now be supporting it more then it should. Any help or ideas would be nice. I cant get in my head the idea that the new throwout package thickness is both thicker and needs more throw, which I guess would be called for for my bent fork idea.

[gjz30075]

I didn't realize the platen could be cut off the pressure plate. Is it possible there bent pp fingers because the platen is supposed to take the brunt of the force and not the fingers on that type of pp?

[types26/36]

I didn't realize the platen could be cut off the pressure plate. ?

Unless I am wrong I dont think Mini64 meant he actually "cut off" the plate, I assume he meant he has dispensed with it by fitting the pressure plate that does not have the plate.

[mini64]

well, i do mean cut off - apparently that is standard procedure according to the guys at Dave Bean.

[types26/36]

i do mean cut off - apparently that is standard procedure according to the guys at Dave Bean.

I wonder why when the pressure plate without the thrust ring is freely available

[john.p.clegg]

And are the ends of the fingers the correct shape?

John

[gjz30075]

Are you having trouble getting the throwout bearing with the flat face?? I'm really surprised the guys at DB suggested this.

[garyeanderson]

I have done the exact same thing, the flat platten is removed and the round face throw out bearing ride on the fingers. This is the same info I got from Dave Bean 8 or ten years ago. Its in his Catalog under clutchs. Did you put the .400 inch spacer in to get the proper stack up height after removing the flat face platten?

Gary

[bcmc33]

I am clearly missing something here!!!

For my education, what is this change meant to achieve?



Brian Clarke

[types26/36]

For my education, what is this change meant to achieve?

Well I dont know why the original pressure plate is modified but if the pressure plate with no thurst ring is fitted you can then use the 8.5" clutch plate (as per 5speed Lotus g/box) as the original (4speed) is 8"

[bcmc33]

I still don't understand - probably because I'm too thick.

Someone draw me a picture.


Brian Clarke

[garyeanderson]

Hii Brian
What don't you understand, the 8 1/2 " clutch or why someone would stock one kind of Presure plate that can work with 2 different diameter clutches (8 and 8.5") and two different plattens (round or flat)?

Gary

Ps I have the 8.5" clutch disk in my S2, it has a 1700 cc twin cam. torque was 133 lb/ft on the engine brake and I didn't want problems. So far I havn't had any.

[bcmc33]

Gary,

What I don?t understand is the original proposition of removing the platen so that the fingers are contacted by the release bearing.
I take it that the object of this modification is to effect an improvement in the clutch operation ? this is what needs to be explained so that Thicko here can understand.


Brian Clarke

[garyeanderson]

In the U.S. I think its just economics, Dave Bean only has to stock the ones with the Flat platten. He probably gets a price break on a certain number and if he buys 50% of each, no discount. i'm only guessing on this. The 8 vs 8.5 inch clutch is probably the real reason for it all.

[mini64]

my last reply didnt post because i had an internet address in it-oops

To try and answer everyone's questions: Yes, i thought there were no more flat face bearings available. Last time i changed the bearing Bean folks told me they were in short supply. this time around they didnt offer me the choice, so i figureed there were no more. I have since found out other sources have them.

They offered me a new bearing carrier that would get the spacing right for my new round nose bearing, after removing the p-plate platen. Interestingly, as someone pointed out, their catalog shows spacers to do this on the original bearing carrier. I guess they now have incorporated this spacer in the carrier. What i find interesting is that their catalog shows the spacer for a 7 to be about .1 inch different then the spacer for an elan. Are they talking about a pushrod 7 and not a twin cam i wonder, else why would these be different? Anyhow, my new vs old release package are about 0.1" different in height. Did they send me the wrong one? I havent investigated this yet.

For those curious, here is a side-by-side comparison of the two bearing/carrier types:

address deleted

The Bean guys dont know what i am doing wrong to cause this problem (and yes, it is usually me doing something wrong...). I have about decided it is my crank pilot bearing grabbing the gearbox input shaft enough to affect a locked system, as my box input shaft can wobble quite a bit. I am going to space out the clutch fork pivot point to give me more travel before interference of the fork to the bell housing hole it goes thru. Anyone know if it is possible to have too much throw in the sytem? Is there a positive stop in the p-plate, or will you bend the fingers or soemthing else if you have too much slave throw?

Thanks everyone for their help!