Installed Twin Plate And Clutch Wont Disengage

[a31lunacy]

hey all well we just finished a rb26 conversion in the ceffy and when it came time to put the car on the dyno the car would not disengage with the pedal all the way to the floor.

the clutch is bled fine, we are running a rb25 gearbox and a direct clutch services solid centre twin plate clutch + flywheel with the standard rb25 thrust bearing(new of course) + fork pivot(not spaced).

now we wound the adjustment at the clutch pedal to its maximum and this fixed the problem but the clutch pedal HAS to be touching the floor hard to disengage the clutch and over time obviously when the clutch wears slightly the same problem will occur so what can we do. also i am not going to risk things in regards to hard gear changes while the car is like this want it fixed before i start giving it a load.

to fix this problem i'm thinking maybe a spacer and upgraded fork pivot ??? or i have read about the use of different thrust bearings and carriers being used with all the jap brand clutches has anyone had experience with these particular clutches ???

also im thinking whilst this is going on mabey a braided line and by passing the jointing block would help things slightly ???

any help would be great

[a31lunacy]

and i dare say i'm still using the rb20 clutch system that was on the car orig even though it was rb25 when i got it

[a31lunacy]

anyone ??

[R34GTFOUR]

Hate to say it but I'd say its a gearbox out job. If the car still wants to "drive" with the pedal pushed in the clearances arent right. Was it a custom clutch? what pressure plate was used?

A mate of mine had some super duper custom twin plate for his XR6T and it took us forever to get it right. It took 3 different places to setup the clutch before the clearances were correct. Thats why i just go the jap stuff now

[a31lunacy]

yeah i know its a gearbox out job i dont mind that im just after a few suggestions on how to fix it but im thinking putting a spacer on the fork pivot and up grading it whilst im at it

[Sick_R31]

to fix this problem i'm thinking maybe a spacer and upgraded fork pivot ??? or i have read about the use of different thrust bearings and carriers being used with all the jap brand clutches has anyone had experience with these particular clutches ???

I haven't used this particular clutch but my exedy hyper twin i bought gives you the recommended sleeve length on the bearing carrier. The recommended length is 14-16mm, i don't know if that will be the case with your clutch. Here are all the nissan part numbers for different sleeve length bearing carriers. Hope that helps.

30501-A3800 12mm, 30501-N1601 14mm, 30501-U0200 16mm, 30501-S0200 18mm, 30501-B6000 20mm, 30501-S0160 22mm, 30501-K0404 24mm, 30501-K0510 26mm, 30501-N1600 28mm, 30501-N8400 30mm

[a31lunacy]

cheers mate i think ill just ring direct clutch and have a chat with them tom but that will come in handy

[_Wing_]

im going to put my money on the standard rb25 thrust/throwout bearing/carrier is the wrong height for your clutch kit

[a31lunacy]

no your money is mine i spoke too direct clutch and they designed the clutch to be used with the standard gear he said the only times they have run into trouble the solution is to re sleave the slave 1 size smaller to get more stroke

[PLYNX]

Checked that your clutch pedal box aint broken ?

[femno]

Does the clutch hold on under power?

You may need to make a longer pushrod for the slave. Do that and take as much play out of the pedal as possible.

[_Wing_]

if they say OEM everything works and you've 100% checked everything between your foot and the slave (easiest and cheapest to do), and you installed a brand new clutch kit correctly (can't really go wrong much if you've got the box in and car running), then there's not much else it can be: fork/pivot/carrier/bearing

[vspec_gtr32]

same thing happened to my gtr, bled it up and the clutch pedal was hard, and it would still be in gear when the pedal was pressed..

had it towed to all brake and clutch and they removed and re-fitted the gear box and fixed the problem, $780 including the tow..

turned out that my mate who had "worked in a gearbox workshop before", installed the twin plates wrong, they were facing each other instead of the oppposing each other....

who installed ur clutch, because if u don't do it ur'self you never know???

that's my 2 cents

[femno]

HAHA thats an awesome story...just goes to show what can happen with backyard mechanics sometimes LOL

[MBS206]

I'd also be checking you haven't snapped the mounting brackets off the firewall for the clutch pedal...

I snapped the top one off with my setup, and could only JUST get the thing to disengage.

[STATUS]

edited.

Edited May 18, 2009 by URAS

[xris]

Strange im having the same issues with the same clutch hmmmmm..... so bearing carrier lengthened will fix this hmm DSC told me bearing would be fine standard...which it isnt apparently

tried

replacing nismo slave with standard slave

replace braided line with solid

replace clutch master with another that worked in our track car.

spaced pivot ball out

removed dust plate from engine/box to get it closer.

was looking at cut and shutting the pivot ball to make it longer (got it spaced out 10mm atm to compensate for the 10mm thick adaptor plate (gearbox/engine)

bearing carrier will be a better idea by the sounds of it making it sit closer than the standard one im using atm...

OP what was your resolution to this problem??

Edited August 31, 2010 by xris

[xris]

As above ive got the same clutch and had the same problem with it as the OP. Now ive had my slave resleaved and it worked. BUT...it was super heavy and still at the bottom (about 15mm off the floor). short story engines bearings died and its apart again.

Now.....if i change the bearing carrier over. to a thicker unit will this increase the height of the release point? im looking at trying to make this more user friendly (hopefully i can change the bearing over and swap slaves back to normal and have not so much a 10kg spring to push.

will that fix my issue? and what is the standard sized bearing 12mm?

[xris]

there we go problem solved . old and new

[bubba]

Sorry for the resurrection but it hasn't been dead for that long..

Anyone know where I can source one of these smaller diameter release bearings/carriers? or have a part number?

Cheers!