clutch problems

[warner01]

Im not sure if this is localised to me due to the motor conversion but has anyone ever had the clutch not work when under full noise.
When driving normally at lower revs it works great its easy to use and changes perfect but if ive been say over taking or climbing a dune after reving the motor out when i push the clutch pedel it wont dissingauge until you lower the revs and let it build peassure up again.
I thought maybe the vacume could be taken off the booster maybe but the non return in the vac line is working fine as far as i can tell.
Im a little confussed has anyone else had this problem???

[Family4x4]

Symptoms sound like a worn clutch.

[warner01]

no all new stuff. only had the motor running for about 4 months and clutch isnt slipping it just wont release under full power, but it works fine under light throttle.
thniking maybe the booster has a small leak and it needs constant vacume to keep it working. That would only be a guess though. just seeing if its ever happened to anyone else to save me bying stuff i dont need.

[love ke70]

it will work even with no booster, not all GQ's had a booster, the pedal just gets heavier.

does the pedal depress or will it not even go down?

Why are you trying to clutch in under full load?

[warner01]

yes the pedal will depress but clutch stays engauged. im not trying to change under load but after a full throttle run up in revs it needs a good 5 - 10 sec off the throttle before itl work, so if ive just reved it out to overtake for example then when you go to change up a gear it wont release till youve been off the throttle for a period of time. or when going over a big sand dune if ive been going flat at the bottom when i go to stop as i come over the top the clutch stays engauged and i have to stall it out. the clutch does work fine at lower power levels ( less revs / throttle )

[love ke70]

Can you set up a go pro to watch what the fork does when you press the pedal after a full noise run? If you can work out if the fork is moving in time with your foot or not you will atleast make tracking the issue a bit easier.

Did you grease the splines etc when doing the clutch install.

[Parksy]

Are you sure it's clutch related and not gearbox related? My xr8 used to get difficult to shift when I put the go pedal down hard.

Have you checked the clutch pedal adjustment? There is a clevis pin that is adjustable directly behind the clutch pedal, I think the manual has a figure that it needs to be set to that I can't remember off the top of my head.

[pearcey]

G`day mate
Sounds more gearbox related than clutch.
If it comes out of gear but wont go into the next gear I would be looking at the gearbox.
If it wont come out of gear it may be clutch related but it seems funny as under normal conditions it works OK.
The clutch should release about half way to the floor but if its right on the floor then you may have to check the hydraulics, the booster should not have any thing to do with it as it only gives assistance. The pedal is virtually directly connected to the master apart from a very small movement in the valve which opens to allow atmospheric pressure into the rear chamber to give you the power assistance.

[warner01]

So Parsky your saying theres an adjustment behind the pedal. i didnt know that. but will have a look. yea it releases a bit closer to floor than id like but ive attributed it to the crappy dellow conversion bearing thats too short. ive already adjusted the fork in the box out as far as i can make the bolt strech without having no thred left. its just strange it only has problems under full noise. the box hasnt been far and its from a td42 plus it feels good to use, so not saying thats not a problem but i seriously doubt it. could the booster be leaking into the master causing a vac and bleeding it back maybe??? i know its far fetched but im clutching at straws ( pun intended ). dont own a go pro and the exhaust heat would concern me. but i will look into that see if i can use one.
its very difficult as it is perfect under normal driving. could heat from the exhaust be a factor maybe??? cos thats close i guess wouldnt have thought any more than td would be though.

i appriciate the help too guys...

[pearcey]

So Parsky your saying theres an adjustment behind the pedal. i didnt know that. but will have a look. yea it releases a bit closer to floor than id like but ive attributed it to the crappy dellow conversion bearing thats too short. ive already adjusted the fork in the box out as far as i can make the bolt strech without having no thred left. its just strange it only has problems under full noise. the box hasnt been far and its from a td42 plus it feels good to use, so not saying thats not a problem but i seriously doubt it. could the booster be leaking into the master causing a vac and bleeding it back maybe??? i know its far fetched but im clutching at straws ( pun intended ). dont own a go pro and the exhaust heat would concern me. but i will look into that see if i can use one.
its very difficult as it is perfect under normal driving. could heat from the exhaust be a factor maybe??? cos thats close i guess wouldnt have thought any more than td would be though.

i appriciate the help too guys...
The booster is a direct link and it doesn`t matter if there is vac or not, it will still work only be harder to push down.

[warner01]

yea i get that pearcey but since its an odd/ rare problem i thought maybe the booster could have a small vac leak into the master and bleed the fluid back under high rpm. but then it would prob work the other way though as in have higher vac on idle maybe. i dunno. maybe ill take the vac line off alltogether and use it as a un boosted clutch see if that is the problem or not.

[love ke70]

if you do that, cap the booster to stop dirt getting in and plug the line to make sure you dont lose your brakes when you have no vacuum.

definitely worth a crack though.

I still think you need to go pro it...

or strap a small mate underneath? hardest thing will be knowing when you are pressing the clutch in relation to when you are getting movement.

I am wondering if its a bleeding issue manifesting itself when the extra exhaust heat is present.

[warner01]

i deff like the idea of strapping a mate under the car. lol hahaha. yea i get the feeling you may be right with the bleeding. i got my doubts its the booster but hey cars can do some strange stuff. maybe ill look into heat shield around the slave, and maybe rebuilding or replacing it.

[love ke70]

patrol clutches can be a nightmare to bleed if you empty the system.

Did you empty the system when doing the conversion?

bosvelk ended up bleeding his backwards with a massive syringe, as the pedal travel was not enough to push a big airlock out of the loop...

[Bushy674]

Interesting problem mate, the fact you can't get it out of gear points to clutch disengagement issue, funny thing how they have a T bleeder in the system, although generally if they are not bled correctly they won't work well at any speed. What conversion have you done, have heard in the past that some aftermarket bell housing adapter kits can play merry hell with the clutch, usually shorter life or weak. Let us know what you find, sounds like a bastard of a problem though....

[warner01]

sorry havent been on here in a while. ive got a 1uzfe with a dellow bell housing and yea its a shit housing and did cause me problems. but none of this explains why it works fine until i give it hell. and not straight away either as ive not had the problem for a while now. im thinking its gota be heat related. i didnt think the exhaust was too close but maybe it is. yea the bleeding system is pretty odd. but i think its all bled up fine. Bushy if you look up 1uz maverick on here youl find my bus.

[love ke70]

maybe try getting it pressure bled or doing it the big f#*k off syringe way, just to eliminate a variable?

[warner01]

could try that. ill have another attempt at bleeding it. when i did bleed it if i opened the bottom nipple ( hehehe nipple ) it would slowly run out. after i closed it i tried getting bubbles out from the top and bottom but had none. so ill try a syringe cos any things worth a shot once. thanks rolla man ;-) lol

[love ke70]

hope it helps :)
funnily enough, put a supra motor in a rolla and you learn all sorts of things about things getting hot that you never may have considered a problem in a normal car, possibly much like you in this instance.
Although that said, the exhaust in my GQ is sooo close to the clutch slave its ridiculous and I have never had a problem, always seems to be if the clutch slave/master gets emptied and gets an air lock in one of the bends. yours may just be tiny and only creating an issue when hot...I dunno.

If you do fix it, please tell everyone what it was :)

[warner01]

lol a supra motor wow that would be a tight fit. yea ill put up the end result when i get it. ive been way to flat out to try these things yet but i might get a chance tonight.

[warner01]

ok i think ive sorted my clutch. its been a bit hard to test as i havent been out 4wding since. but on road it seems to be good. so what i did was put a longer shaft in the slave cylinder. my thoughts are maybe under full noise it was causing more vacume on the clutch pulling it slightly further out causing the slave to go to far and loose the fluid. its either that or it bleed up while i was stuffing around making the new rod for the cylinder. thanks for your help guys. now to go out and show up some more cruisers.

[love ke70]

good to hear, keep up posted if it comes back!