Rb25 Box Creeping When Clutch Engaged?!?

[xris]

Hi Guys.

Ive got a Rb25 gearbox in my 180 (connected via a conversion plate to my CA18). Heres a run down of what ive got

The Gearbox is bolted to a 10mm thick conversion plate.

Standard Clutch Master

Maltech Braided Clutch Line

Nismo Big operating cylinder

Nismo pivot bolt

Ive spaced the pivot bolt out 10mm to accomdate for the gearbox being moved 10mm back. Now the problem is. Ive bled the system.(a number of times.)The slave rod moves in and out. ive got peddle feeling. It makes its twin plate rattle when i put the clutch in.....BUT its hard to put into gear and when you do the wheels start turning (while im on the hoist) while the clutch is depressed. Ive tried replacing the push rod with longer rods but still that doesnt work. tried adjusting the peddle in the car out fully nothing...

Ive had the box and engine out 2 times now to try and fix this problem (originally it worked, took it for a drive and it just started to slowly creep when i put the clutch in...weird. then it just started getting worse.)

First time. - spaced the pivot ball out with 2 washers - no good

Second time. - spaced the pivot ball out 10mm (3 washers) - still no good.

So it originally worked. then got worse and now doesnt disengage the clutch (clutch visably looks fine).

Could the nismo cylinder be stuffed (it was brand new when i put it on). Thinking of buying a cheap OEM replacment slave and seeingif this fixes the problem.

Any ideas or solutions would greatly be appreciated. as ive had a gut full of this pos.

thanks

Neil

Edited August 19, 2010 by xris

[Moodles2]

I think the Nismo slave is the problem, iirc they're supposed to be used as a pair (Nismo master & slave), also I've read when it comes to twin plate clutches only the Nismo coppermix twin plate is compatible.

[xris]

Yeh did a bit of research and found out that this is the problem

just went and bought one of the last Rb25 slaves in the country from nissan lol (out of stock). Not too bad. Trade price $80.

Had a read of this thread sounds all to similar.

http://www.gtr.co.uk/forum/80110-nismo-sla...aided-line.html

Edited August 20, 2010 by xris

[battery]

i had a similar problem when i had installed the wrong clutch kit...

the clutch kit was the correct one for the car but for some random reason it wouldn't work so i took the old clutch that worked into a clutch shop and got a replacement that matched it.

turns out there was a height difference between the old and new clutch and thats why it wouldn't work.

i have been told you can get different size thrust bearing carriers also which may have helped..

[GTR1993]

if u have the clutch engaged and the box out of gear it will spin the wheels if they are not on the ground, happens all the time? Also when the clutch is depressed it is not a zero friction system.

[xris]

i had a similar problem when i had installed the wrong clutch kit...

the clutch kit was the correct one for the car but for some random reason it wouldn't work so i took the old clutch that worked into a clutch shop and got a replacement that matched it.

turns out there was a height difference between the old and new clutch and thats why it wouldn't work.

i have been told you can get different size thrust bearing carriers also which may have helped..

Could be a reason. BUT have adjusted the pivot ball (as this is what you do to fix that issue) and this did not help so thats not it.

[xris]

if u have the clutch engaged and the box out of gear it will spin the wheels if they are not on the ground, happens all the time? Also when the clutch is depressed it is not a zero friction system.

Wheels start spinning when i put the clutch in and put it into gear. out of gear wheels dont spin (clutch is not disengaging).

[DVS JEZ]

because you said it was ok then got worse it is a Hydraulic issue, either master cylinder is leaking internally or the slave playing up, normally the slave will have an external leak

[GTScotT]

If the slave cylinder swap doesnt work, I would be trying a different clutch kit.

Basics, unfortunately with custom setups they are the hardest to work out lol.

[NYTSKY]

Have you tried adjusting the main cylinder behind your pedal?

[xris]

ive tried adjusting the U bolt thingo that bolts to the pedal. had that wound out the furthest it would go made alittle difference. im leaning towards it being the throw out bearings width is too small.

On the weekend i double checked everythin

- replaced nismo slave with standard new nissan

- replaced master

- replaced the line

- rebled and it still didnt work.

Im going to pull it all out and do some measurements and purchase the correct sized bearing, as after reading the below thread (same clutch and gearbox as me with the same problems....) it looks like its the bearing (only thing that hasnt been changed)

http://www.skylinesaustralia.com/forums/In...ml#entry5423007

Edited August 31, 2010 by xris

[THENIG]

ive tried adjusting the U bolt thingo that bolts to the pedal. had that wound out the furthest it would go made alittle difference. im leaning towards it being the throw out bearings width is too small.

On the weekend i double checked everythin

- replaced nismo slave with standard new nissan

- replaced master

- replaced the line

- rebled and it still didnt work.

Im going to pull it all out and do some measurements and purchase the correct sized bearing, as after reading the below thread (same clutch and gearbox as me with the same problems....) it looks like its the bearing (only thing that hasnt been changed)

http://www.skylinesaustralia.com/forums/In...ml#entry5423007

I have had a similar problem with 25 conversion in 32 with 25 gearbox. I originally had to use the heavy duty full face organic clutch I had fitted to the rb20, after the 25 conversion it slipped straight away so I had to get it replaced with a 5 puck (not my decision but its all they had at the time & i couldn't leave the car there any longer). Ever since I got it back the clutch would not completely disengaging so we tried adjusting (improved it a bit) then decided to replaced master which didn't fix the problem either. My bet has always been on wrong throw out bearing, mechanic who did the work claims it was replaced but 6 months down the track the throw out bearing makes noise so I am betting its the old one from the RB20 clutch in there. I won't know until I pay to get the box ripped out again.

I am very curious to see what is the width of the throw out bearing you pull out and what size of bearing you put it so can you please update the thread when you sort it out.

Cheers

Rob

[xris]

no worries mate. i think everyone will know when i get this sorted!

[xris]

Hi Guys. Finally got this sorted (to a degree). I had the standard clutch slave resleaved to 5/8th($125 later) and now the clutch disengages. clutch point is very low to the ground and the clutch is super heavy now (ratio is now 1-1).

Edited September 30, 2010 by xris

[THENIG]

Hi Guys. Finally got this sorted (to a degree). I had the standard clutch slave resleaved to 5/8th($125 later) and now the clutch disengages. clutch point is very low to the ground and the clutch is super heavy now (ratio is now 1-1).

Good to hear, did u have to pull the box out again before you worked it out??