New clutch, worse problems

[mh007]

Originally Posted by bubs

Well drove to work this morning (35miles) and the gears crunched again by the time I got here. So car seems fine when cold but crunching when warm.

Biting point is near the floor and I can't find any leak so either air got in the sytem again when bleeding it or possbile master gone up the wall and letting fluid through the piston but not externally leaking? (i assume it has some form of piston?)

When we did the clutch change we noticed the flywheel didn't seem to have any movement in and out, the tollerance on rotation was around 20mm. Should there be any in/out movement?

The Dual Mass Flywheel will have play between the masses (25-30mm max) thatis, it's like a wheel within a wheel so the outer part will have movement while the inner stays still.

Your unlikely to much inward/outward movement but you may have some due to end-float on the crankshaft.

And yes, fluid can escape back into the master cylinder without externally leaking.
This is not your problem though !

It sounds like hydraulic failure to me.

You could have a faulty pressure plate/cover assembly which may give crunching gears but that is unlikely to alter the biting point to the degree your getting.

I would suggest master cylinder or even a faulty slave !!

[bubs]

Thanks, everything at the moment seems to be pointing towards the master. Hopefully it's not the new slave unit, i used the freelander one but had to bend the pipe slightly to mate with the master but i've checked all the pipes and joins and there's no sign of leakage from them and i don't think i'm losing fluid at all.

Had enough of this job with my last car. It was a vectra B and the slave cylinder on that was noisy so we took the whole thing out (similar job to the 75) and it ended up leaking so my brother re-did the job 3 times with 2 new parts (all OEM direct from vauxhall) only to find the new parts were not made to spec and even though they looked the same the sleeve was obviously ever so slightly larger causing gearbox fluid to escape past into the bellhousing.

[kaiser]

Most of the times the seals are the problem. They are inexpensive.
Any normal brake fluid will do.

[mh007]

I've never understood why manufacturers put the slave inside the bell-housing (apart from making it a lot more work of course !)

Some (but not many) still have the sense to position it outside the gearbox.

I really do think your problem is master cylinder as it's very common on the 75 ZT after a clutch/slave replacement.

Good luck with this.

[bubs]

It's probably cheaper to make one that sits along the shaft inside, also means more money for them when it goes wrong.

Just thinking would the master cause the problems straight away or is it because it might be letting a small bit past and into the resevoir everytime i use the pedal and evetually gets worse the more it's used. Ie it's not happened after getting warm but rather due to more usage of the pedal. The pedal still comes back up quickly but i assume that may be due to the spring pulling it back?

[FrenchMike]

Originally Posted by kaiser

Most of the times the seals are the problem. They are inexpensive.
Any normal brake fluid will do.

Here the seal of my leaky slave:
Yes,i's a matter of rubber and chemistry .

However,you can see only the rib in contact with the bearing (hottest) is concerned ...



Mike

[FrenchMike]

Originally Posted by bubs

It's probably cheaper to make one that sits along the shaft inside, also means more money for them when it goes wrong.

Just thinking would the master cause the problems straight away or is it because it might be letting a small bit past and into the resevoir everytime i use the pedal and evetually gets worse the more it's used. Ie it's not happened after getting warm but rather due to more usage of the pedal. The pedal still comes back up quickly but i assume that may be due to the spring pulling it back?

Hi,

It'is the strong springs of the diaphram which push back the pedal via slave
'piston',fluid and master piston :

(forget the arrow)


Mike

[bubs]

ah, that makes sense then I suppose as that's all new.

[bubs]

HELP PLEASE! The new master is in and it's still not going in gear properly. The pedal is now very stiff again and it seems like the clutch isn't disengaging properly (ie bite point too low for pedal). Any ideas please as I can't keep throwing money at this car, it's already cost me over £450 I really don't have and the problem is worse as i now can't even drive it. I've got a feeling i'm gonna end up trying to take the box out again Should I try bleeding it again? (i was under the impression the new master came pre-filled)

[FrenchMike]

Originally Posted by bubs

HELP PLEASE! The new master is in and it's still not going in gear properly. The pedal is now very stiff again and it seems like the clutch isn't disengaging properly (ie bite point too low for pedal). Any ideas please as I can't keep throwing money at this car, it's already cost me over £450 I really don't have and the problem is worse as i now can't even drive it. I've got a feeling i'm gonna end up trying to take the box out again Should I try bleeding it again? (i was under the impression the new master came pre-filled)

Yes,the master comes pre-filled ..

Do the gears change smoothly engine stopped ?

See how was the pedal after repair:

clutch.jpg