Clutch Master Cylinder repair?

[jonathan63]

Mine is well on the way out. Has been for months.

Is it possible to repair or replace the seals or not?

[FrenchMike]

Mine is well on the way out. Has been for months.

Is it possible to repair or replace the seals or not?

It's depending on you have fluid loss or not ..

[jonathan63]

Mine is doing the "staying down" trick. It might also be leaking a bit as well (weather too wet outside to go look just now).

Its started to squeak as well which makes me think that it might be leaking.

[FrenchMike]

Mine is doing the "staying down" trick. It might also be leaking a bit as well (weather too wet outside to go look just now).

Its started to squeak as well which makes me think that it might be leaking.


Cost nothing to have a close look at this little valve /seal:

43822

If dirty,that's the problem :D

Mike

[jonathan63]

Cost nothing to have a close look at this little valve /seal:

43822

If dirty,that's the problem :D

Mike

Really!? dirt in this seal will cause the common "staying down" issue with the CMC?????

[FrenchMike]

Really!? dirt in this seal will cause the common "staying down" issue with the CMC?????

Yes, the valve can't close and the fluid return to the reservoir !!!

43824

[DMGRS]

Really!? dirt in this seal will cause the common "staying down" issue with the CMC?????

Yep - Mike did a great thread on the subject some time ago. A very interesting read. :)

[roverbarmy]

Mine has been much better since I bled the clutch right through. Loads of gungy fluid came out at the bleed screw end, so I just continued to bleed until it was all good, clear fluid. It was nine year old fluid so hardly surprising. (We change brake fluid regularly so why not clutch fluid?) I also took out the black condom from the master and cleaned that, before putting it back as it seemed to be covered in black slime. I also lubed the ball and socket joint with white grease. It's much smoother now.
Mike

[DMGRS]

Mine has been much better since I bled the clutch right through. Loads of gungy fluid came out at the bleed screw end, so I just continued to bleed until it was all good, clear fluid. It was nine year old fluid so hardly surprising. (We change brake fluid regularly so why not clutch fluid?) I also took out the black condom from the master and cleaned that, before putting it back as it seemed to be covered in black slime. I also lubed the ball and socket joint with white grease. It's much smoother now.
Mike

Clutch fluid doesn't get contaminated with moisture from the air like brake fluid does - but I agree with the sentiment. Given how much rubber particles it holds in suspension, it's a good idea to change it every couple of years.

I usually flush through every new car I buy (both brakes and clutch) but thanks to a brilliant bit of design, I can't do that with the new MG ZS - it's a sealed syetem. :duh:

[TimWD]

I recently had need to replace my Rover original plastic master cylinder (it had done about 50k miles). I had read previously about rubber particles contaminating the fluid and effecting the small seal in the master as identified sometime ago by French Mike. I too found some evidence of rubber particles in the fluid that remained in the master when I removed it. This set me wondering if this could in fact be caused by particles entering the master originating from the sound insulation in the footwell. I had bled the clutch every two years to renew the fluid but always struggled to remove the master cylinder cap as it rubs so tightly on the insulation. The new master being slightly worse in that respect.
Only a theory but it may be prudent to try and cut away some of the insulation near the cap so that the turning of the cap does not dislodge any particles that could find their way into the master when struggling with fluid top up.

[FrenchMike]

I recently had need to replace my Rover original plastic master cylinder (it had done about 50k miles). I had read previously about rubber particles contaminating the fluid and effecting the small seal in the master as identified sometime ago by French Mike. I too found some evidence of rubber particles in the fluid that remained in the master when I removed it. This set me wondering if this could in fact be caused by particles entering the master originating from the sound insulation in the footwell. I had bled the clutch every two years to renew the fluid but always struggled to remove the master cylinder cap as it rubs so tightly on the insulation. The new master being slightly worse in that respect.
Only a theory but it may be prudent to try and cut away some of the insulation near the cap so that the turning of the cap does not dislodge any particles that could find their way into the master when struggling with fluid top up.

Hi,
I don't think so ,i never opened mine before .
The small rubber particles come from the slave seal (rear rim)

43829

Mike

[TimWD]

Mike,
I wasn't disputing your very useful diagnosis of master cylinder small seal failure and consequential master cylinder failure. My point was more to highlight and be aware that fragments of the footwell insulation disturbed when removing the master cylinder cap could enter the hydraulic system. I have always been taught that hydraulic systems must be kept free from contamination otherwise failure of components will occur. Any foreign matter entering the system could then contribute to costly slave failure.

Regards, Tim.