Outer Limits 4x4 Board

hey guys, got one i cant solve for ya's

it all started yesterday morning when i went to leave for work, and had no clutch, had a look, no fluid.
so put some fluid in it, and drove it to work with the clutch system full of air and just rev matching cause it wasnt moving far enough.
by the third job i went to, the clutch was working alright, well enough for me to grab my trailer, and go pick up my project car from the shop, and tow it home, and get a new clutch master cylinder on the way home, as the reason for the lack of fluid was a leak out of the rear of the master.

so i fitted that last night, bled it, from both points, and gave it a quick test, felt perfect.

left for work this morning, and its fine, 10 minutes down the road, the bite point is coming up higher and higher up the travel, to the point where the clutch is slipping under average accel, and on hills.

got it to work, did what i had to do, and 4 hrs later drove home, seemed fine, but alas, again the bite point came up and the clutch started slipping again.

i spoke to the bloke in the store, who said put a couple of washers between the master and the booster, and this will fix it, but my issue with this is, it will fix it when its pressurised, but i doubt ill be able to get enough movement to use the clutch when its cold and not pressurised.

when i got home i pulled the booster out, set the pushrod lengths and reinstalled, and also set the pedal height.

when i re-installed the pushrod did not match the pedal height against the stop, so i wound it out some more to get the pedal up to the height its meant to be, with the correct free play etc

took it for a drive, did exactly the same thing, really, no difference. none.

re-bled the system but it seemed air free.

so ive got the shits with it.

who knows whats going on here and can tell me what to do? is it the master cylinder faulty?

cheers, andy

Brake fluid in the booster?
buggered one way valve in the vaccum system? ( where id be lookin!)
scored bore in the slave, stopping it from going all the way back?
Is it the right master?

Hope this is some help thats a curly one!

Steve.

Put new slave cylinder in it.

am getting another new master for it, will see what happens.

only happened post install of new master, was all working well before hand, minus the running out of fluid due to master leaking scenario

if that doesnt fix it, i will check these things posted.

why new slave V8patrol?

i had the same issue sunday night, stab the clutch and it would slip, so i jumped under and adlusted the pedal, still not perfect but better, monday was fine not a problem, have a brand new slave on mine also

ok, another new master, still no joy, doing exactly as described

bizarre considering all was good until i replaced the master :(

so, are we all thinking slave now?

anyone wanna tell me why its the slave?

im thinking it might be, considering the proximity of the exhaust to the slave, would be the most likely to be affected by the heat

i dunno though :(

similiar thing happened to me. once you replace the master with a part that works at 100% it puts extra pressure on the parts that have been running at 70%. maybe the fluid is leaking internally around the slave cylinder seals but the fluid is staying in the cylinder therefor pressurising the system.? i had a mq that was doing similiar things but the slave had been resleeved for some reason and the sleeve was slipping in and out jamming the rod and holding the clutch half on.

im gonna say its a design fault in the aftermarket master i was getting, put my old one back on, and its perfect.

grr

any further ideas or speculation is appreciated

-ET 4wd- wrote:Brake fluid in the booster?
buggered one way valve in the vaccum system? ( where id be lookin!)
scored bore in the slave, stopping it from going all the way back?
Is it the right master?

Hope this is some help thats a curly one!

Steve.

I'd be looking at the one way valve also. It's cheap and odds on its this..

mate, i've just gone through this in my hj60 landcruiser. i know. this is nissan! but i tried replacing both master and slave twice. same result each time. ended up persevering with bleeding both master and slave. it now works fine. this issue was not fun when i discovered it in the vic high country, on a goat track. good luck. it pressurised that much it blew the piston out of the slave and jammed the clutch up hard.
scott

yeah mate, the verdict is the pushrod just needs to be shortened a touch. it must be getting held open by the smallest amount when you bolt it on. which blocks the return.

yet to fit the new one though...

quick follow on to this.

just changed the slave from the early eighties model to the later model slave that came with the 5 speed boxes. about twenty mm longer stroke length. now it( the piston) stays in the barrel and doesn't wobble and pop out.

may help with your issue.

scott

love ke70 wrote:yeah mate, the verdict is the pushrod just needs to be shortened a touch. it must be getting held open by the smallest amount when you bolt it on. which blocks the return.

yet to fit the new one though...

X2

I (sort of) had the same problem. my clutch would work fine until the car got hot then the clutch would slip.

The way to test if you need to adjust the pushrod is to get under the car and try to push the slave cylinder piston into itself (moving the clutch fork so the thrust/throw out bearing is moving AWAY from the pressure plate) it should be easy to push all the way in with the heal of your hand. If its not, then it is resting the thrust bearing against the pressure plate with too much force making your clutch slip.

to adjust remove the two nuts holding the clutch fluid reservior on and move the reservior away. get someone to stand on the clutch pedal or jam it down so the rod pokes out. being careful not to move the rod too much sideways (as i think it lets air past some seals on the rod and makes your clutch feel stupid, which i accidentally did and undid one time.) grab the rod with some pliers or vice grips and use IIRC a 6mm ring spanner to wind the bolt into the rod 1/2 to 3/4 a turn at a time each time re fitting, tightening the reservior nut all the way and testing.

yeah what you say gu town is right.
i ended up having to run it in a couple of turns.
you can just slide the pushrod out, shouldnt need someone on the pedal, or atleast i didnt.

all is sweet now, was just holding it open a fraction when i bolted it on

sweet as. i did two clutches before i worked that out.