R32 Clutch Issue, Rb25 Gearbox Rb20 Motor

[sean133]

Got a clutch engaging issue lads

Installed a good condition rb25 box that came out a car I wrecked

Basically got it done and car could be put into all gears but it wouldn't move

Sussed it out to be a stuck slave cylinder so replaced that with new oem item (everything seemed to lead to this)

Because we took the slave out, fiddled with the pin and put it back in and the car would drive as it should for like 10 seconds then get stuck again

So I bought a new slave but it didn't fix the issue ....

We put the rear on jack stands and took the slave off and the wheels spun in first as they should, speeding up with the revs of the car going up

Clutch slave back on and it'd do the same

On the ground the car would move when you put it in gear, but when foot went on the throttle nothing happened

At 4000ish rpm the car kinda moved a bit which seems like the clutch is slipping

But I drove with this clutch before the box change, and it had plenty of meat left otherwise I would have replaced it

New oem slave, new gktech braided clutch line, bled properly.

Fiddled with the adjustment on the clutch pedal but it didn't change anything

I understand that many people will just say " clutch is gone"

But how?

Basically the issue seems to be either the clutch is slipping which I don't believe

Or the clutch fork isn't retracting properly ,

Is there a way the thrust bearing or carrier could not be going right back in ? Leaving the clutch still engaged a tiny bit so it won't go into gear fully?

Could pivot ball be affecting this?

Could it be a spigot bush issue?

It has a new thrust bearing, pivot ball was good, and the fork wasn't cracked, and I checked it moved nicely and as it should before the box went in.

Appreciate all help and constructive criticism or let me know if I should try something to diagnose further

Thanks guys

And yes I can just pull the box out but id like to diagnose as much as possible before I do it in case I don't need to.

Because I'd like to do drift prac on Saturday

[GTSBoy]

RB25 throwout used, not RB20?

[sean133]

Didn't use anything off the rb20 box, rb25 box has all rb25 parts

[sean133]

Unless I got supplied a rb20 thrust bearing not a 25....

[sean133]

Are they different? Would they cause an issue? If the rb20 one is longer and I got supplied it then it'd be my issue

[sean133]

Nah there the same. Same part number

[jhjones]

Can the slave cylinder piston be pushed back into the cylinder? RB25 release bearing carriers are different to RB20.

Edited March 23, 2014 by H4x

[sean133]

No Free play

Can be pushed right back into it yeah

[sean133]

Don't get how the wheels can spin more to match my revs when the car is off the ground, but on the ground it won't move

[sean133]

Well I do, it means the clutch is slipping because its not under load off the ground,

But it's impossible

[Duncan]

I guess you would smell slipping clutch, but it is reasonably easy to stuff a clutch totally by getting grease on either the clutch or flywheel while it was apart...

[sean133]

I could smell something burning

It all leads to a slipping clutch I suppose

Only theory I could come up with is when the slave was seized and wouldn't fully engage the Clutch before , the clutch was basically worn down to nothing because of it, which kind of makes sense

[sean133]

For anyone wondering, the pivot ball in the rb25 gearbox was too long

Which is very weird because most people seem to just bolt the box up to a rb20 easy

Pivot ball being too long burnt the clutch out hence the smelling/slipping

Got a gktech sr20 one in there now just need to bolt it up and test it out , could possibly still be wrong just need to trial and error

[blind_elk]

No trial and error about it. A few measurements - clutch height, throw-out bearing offset, and a couple of others - and you should be able to tell whether it all fits together correctly.

[sean133]

Yeah I thought of that after I posted

[sean133]

Could figure out where the clutch sits inside the box by measuring then figure out where the face of the bearing will sit at the furthest point the pressure plate is inside the box , then if the fork angle is ok after setting it up I'll know it will work

Just weird it ever happened, no one else seems to have had the issue