Reet, well about a week ago, I got in the car, clutch was fine first press, pressed it again had a bit of play, then more play, more play, until there was just play except for about an inch from the bottom. Got back in the car later on, pressed it, still loads of play, then what felt like a little pop, then nothing at all in the pedal, just play, just how it feels without the master cylinder attached, just the pedal springs. So I looked under the car expecting to see fluid, nothing, tried to bleed it, but without the nipple on I get a bit of blow suck, but with the nipple closed, pedal down then nipple open, absoloutley nothing at all comes out. Removed the master cylinder and tested it, seals were not much cop, so ordered a new piston/seal kit, fitted it today, and it is exactly the same. I have removed all the pipework and just have a line going straight from master to slave. Slave seems fine tho, but there isn't anything else? Also the pedal is doing what it should, i.e. pushing the rod out correctly. So it has to be the slave then? Very simple system, but haven't sorted it! Any ideas?

Also, it has done this twice before a good few months in between, and cured its self over night, and also once, whilst waiting at a junction in 1st, with the clutch depressed, it decided to set off even with my foot buried in the clutch pedal, bit of a twitchy arse moment as there were cars everywhere!

 

Is the slave cylinder the same on any other nissans? I have accounts with GL motors, General Traffic, ASL and Euro car parts, just can't see them having one for a 300zx in stock tho...

sounds like the seals on the master cylinder has gone m8 ...

Sounds like the seals have hyperextended (piston travels too far and the lip on the seal(s) flip over and prevent the seal from sealing

You may have a small leak in your clutch booster? Or maybe a problem with the one way valve on the vac line... assuming you have one that is. lol

.Take the master and slave cylinder off and strip,inspect and clean.The seals can fold over or get a layer of grunge from old b/fluid.Its fairly easy to do..Lee

I've fitted a brand new piston and seals, springs etc in the master cylinder, Nissan oem kit, confident there's nothing wrong with the master cylinder now, but still the same...

Slave seems fine too, but that's what it must be, will get a new one today...

Thought I would update this, found a piece of old rubber seal wedged in the fluid channel from reservoir to cylinder, so fluid couldn't be sucked through...

Glad youve sorted it:balloon: