Clutch Engagement Point Changed After Upgrade

[volcomtruck]

I recently upgraded to a r33 gearbox in my r32 gts-t.

The clutch was engaging even with my clutch foot to the floor when I put the r33 box in. I fixed this by adjusting the clutch rod under the dash.

But now when I put my clutch to the floor and release, the clutch engages 0.7cm off the floor, where previously I had a little more than an inch maybe more before the clutch engaged..

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I'm using an r33 slave cylinder (both the r33 and r32 are 3/4)

I have standard master clutch cylinder (I assume the r33 and r32 are the same bore size: 5/8)

I compared clutch forks between r32 and r33 and they are identical

I compared thrust bearing and between r32 and r33 they are identical in length (r33 is a little fatter, looks more solid but no difference in length)

inspected pressure plate and looks good, my clutch is at 70% and the flywheel was machined originally

I can not adjust the rod off the clutch under dash, there is nothing left I've adjusted as far as it can go

entire system is bleed with no air gaps (did this a few times with no change to engagement point)

I even tried a modified longer bolt to put in the slave, it didn't change anything but thought later on it would do nothing anyway as the master bore size would have to be bigger to push it any further

The only things I can think of now are:

r32 pivot point is 10mm shorter than the r33 one. but measuring both boxes from the pivot point end to the end of bell housing is 5mm difference

I can not simply put on the old r32 pivot point onto the r33 one as (I assume) will make it worse, I am considering putting an extra spacer under the pivot point to raise it up.

I am also considering getting a larger bore master cylinder so that I can push the slave bolt further but r33 and r32 master's are all 5\8

I have read many threads and no one else has seem to had this problem, or they did but simply adjusted the rod or lived with the engagement point.

Has anyone experienced this and have worked through it? any suggestions or advice would be great.

Thanks!

Andrew

[GTSBoy]

I can't help with a fix, but I can report that I put R33 box into R32, no problems with the clutch. Std R32 master, std R33 slave. Put it all together and it worked. Used the same clutch. Only significant change was I deleted the dampener from the hydraulic line and bent the line up a bit to reconnect the slave's flexible. But that shouldn't affect the engagement point significantly.

[volcomtruck]

Thanks GTSBoy

Could you tell me how much play you have before the clutch engages as a guideline?

before when you had r32 box

and after the r33 box went in

just to give me a guideline on where it should be, cheers for the reply!

[GTSBoy]

That's actually a tough question.  I had to put a new clutch master in a few years ago, and ever since then the clutch adjustment has been a pain in the arse.  So back when it was RB20, one day it's got way too much freeplay, so I adjust that out of it.  Then after a short drive all of a sudden there's no freeplay, so stop and adjust some back into it.  Generally, before with the R32 box, the adjustment was close to maximum and only very small adjustements were needed to go from that too-much-freeplay to zero-freeplay condition (like 1 turn).  Now, it is fairly consistent with the new R33 slave cylinder, so I expect that the old slave was mostly to blame.  But the adjustment is still reasonably close to maximum, maybe a few threads from the end of the rod.

I'm generally happy if there is 10mm or so of freeplay at the top of the stroke.  The take up point is well off the floor - probably at least 40mm of travel before it starts biting.  But I'd have to pay more attention to that before you were to trust the number - I've got a Neo in there now and therefore have about 1000% more torque when driving away from stationary, so there's little finesse required with the clutch pedal compared to before.

Edited April 7, 2012 by GTSBoy

[volcomtruck]

So I tried packing the pivot point with a 5mm washer, after removing the 2mm washer, put gearbox back together and no change in the clutch play. still 10mm of travel before biting.

but the clutch fork had very little movement when the gearbox went back in so to avoid further damage as my clutch starts to wear, I pulled the gearbox back out, put the 2mm washer back in, took off the 5mm washer and set it back to normal.

it hurts having to pull the box out twice in a day with no result but that's trial and error I guess, next step will be a larger master cylinder I think, will have to search around for these as I haven't heard of larger clutch masters for my car, just the larger slave, which wont help IMO.