clutch master cylinder or slave?

[deteradz]

got a problem guys and girls after picking up my patrol on the weekend and driving it home the two hours. jumped in the next morning and the clutch pedal went straight to the floor. couldn't build up and pressure. checked the fluid level and it was empty so i topped it back up but nothing. would it be one of the cylinders are shot? if so which one would you reckon it is or better to replace both? don't know if either have been replaced before. any help will be appreciated.

[Bigrig]

Did you bleed it when you topped it up mate? If it was empty, then it needs bleeding to regain pressure and feel. Why was it empty also? Leak??

[growler2058]

Check all lines and bleed nipples for leaks mate and x2 withh big rig you'll need to bleed it again


Tap, Tap, Tap, Tap, what's that freakin noise?!

[Silver]

generally the bottom one - the slave, fails before the master. A mechanic explained to me that in the case of brakes, the moisture that gets into the fluid, accumulates at the low points - the wheel cylinders in that case. I suppose the same applies to disc calipers.

On my Mav, the slave cylinder is also pretty close to the exhaust, which must make life interesting for it.

If your clutch master cylinder is not vacuum boosted, leaks to the outside world that are just starting up should be visible. Mine has a booster, and when the master cylinder (now replaced) leaked, the leak was into the booster and not apparent, from memory, until it had been going on for some time. Back then it was the factory master, and the reservoir was much bigger than the egg cup that came with the replacement :-(.

So, I don't think they generally fail at the same time, with the master lasting longer than the slave. I gather that GQs can be cows to bleed - dunno about the others. I hope these factors help you with your decision.

Doubtless others will be along to share their experience. Edit - I see growlers and BigRig already have!

[4brhino]

Pretty sure it would be the slave cylinder.... mine failed recently, slow leak i didnt know was there until i drove down the road and got no pressure on the pedal. very easy to replace and only $38 from memory. A real pain to bleed by yourself though, try to get someone to help. :)

[deteradz]

cheers guys will try to bleed it this arvo. couldn't see any visable leaks. no booster and its the opposite side to the exhuast. will let you know how i go thanks for the input.

[growler2058]

I gather that GQs can be cows to bleed -

Doubtless others will be along to share their experience. Edit - I see growlers and BigRig already have!

Mine was an absolute mofo to bleed
I eventually had to crack the bleeder and pump the clutch pedal flat out till the fluid came through then with pedal depressed close the bleeder. I tried for hours to bleed it the "proper" way and couldn't get any fluid to come through at all



Tap, Tap, Tap, Tap, what's that freakin noise?!

[stets]

Mate bleeding is easy if you know how.

Back bleed..... Get yourself a 30ml syringe from vets or stock feeders and some clear hose about 5mm int. Dia. Crack the slave cal nipple an the nipple on the block near the passenger side. Using a self bleed kit, put it on the block nipple. Fill the syringe with brake fluid and pump it through from the slave cyl. When the syringe is empty turn off the slave nipple, to fill the syringe again and reopen the slave nipple ti squeeze more fluid into the line. Do this several times, then close off the slave and block nipples. Now take the cap off the master cyl. And start pumping fluid back into the line from the slave. Make sure you do not over fill the master's resevoir. If it gets full, suck some fluid out with the syringe. Once you are happy that it is flushed close te slave cyl. Now flush fluid from the block back to the master cyl again making sure it doesn't over flow. Close everything and check clutch pressure.

It is slow ad tedious. But easy enough to do


Tap,tap,tapping in your head

[GQ TANK]

Once you replace one usually the other fails soon after

[growler2058]

Mine was an absolute mofo to bleed
I eventually had to crack the bleeder and pump the clutch pedal flat out till the fluid came through then with pedal depressed close the bleeder. I tried for hours to bleed it the "proper" way and couldn't get any fluid to come through at all



Tap, Tap, Tap, Tap, what's that freakin noise?!

Doing it my dodgy way got the job done in 2-3 minutes ;-) start to finish


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Tap, Tap, Tap, Tap, what's that freakin noise?!

[MQ MAD]

got a problem guys and girls after picking up my patrol on the weekend and driving it home the two hours. jumped in the next morning and the clutch pedal went straight to the floor. couldn't build up and pressure. checked the fluid level and it was empty so i topped it back up but nothing. would it be one of the cylinders are shot? if so which one would you reckon it is or better to replace both? don't know if either have been replaced before. any help will be appreciated.


The slave cylinders usually go first , being at or near the bottom , they cop alot of the stuff from the roadway,once the rubber boot on the slave cylinder gets damaged, grit gets into the bore and it leaks like anything, if you cant see any leakage from a line or have a split line,to cause the fluid missing,itll be a stuffed slave cylinder
Check the rubber boot on the slave cylinder,if its damaged at all, flick it
Would check this rubber boot, before doin a thing,then go from there

[1nertia]

On Nissans, the bottom end of your clutch system is usually the first to go, like what the other guys are saying, slave cylinder, or the line into it. They can be a huge pain to bleed, so do it whatever way works to get an acceptable pedal pressure. Quite often the bleed nipple on the slave will fill up with crap, as the rubber cover perishes 2 days out of factory. I bleed mine using the pedal, and a pair of multigrips to control the piston on the slave, and the force the bleed nipple to clear, and it works for me fine. Everyone does things differently, quite often with what the book says, mechanics will find an easier method.

All the best with fixing it mate!

[deteradz]

cheers for all the info a simple bleed and i was back on the road. let the fluid run out of the slave bleeder then pumped the pedal got a bit of resistance then jammed abit of wood on the pedal and bleed the master cylinder which air did come out of. repeated it again till fliud waterfalled out. still doesn't explain why it was empty i the first place but so far so good i will keep checking and let you guys know how it goes. once again thanks for all the info.