Clutch Master Cylinder Issues

[LukeAE71]

Clutch Master Cylinder Issues

 

I am having all sorts of issues with this thing and want to see if anyone else has had the same problem or has some opinions/diagnosis :dance:

 

I recently did a manual conversion to my AE71. When I did it I had to drill for the master cylinder holes.

 

The first master cylinder lasted about a week and developed a leak out the back of it into the cabin of the car. At first I put this down to being a second hand master cylinder and replaced it.

 

The second master cylinder has lasted about two weeks and developed the same leak. I am not sure whether I am just unlucky with another second hand one or something else is happening.

 

I am leaning towards me doing something wrong along the way, not just unlucky.

 

On closer inspection under the dash everything appears to be working ok. The shaft goes into the master cylinder straight so it’s not that. The shaft does go all the way in to the end of the cylinder though and I notice there is room for adjustment there. The shaft doesn’t slam againt the end of the cylinder or appear to be forced or stuck, but it does reach the end. I am guessing it is not meant to go all the way??

 

My questions are:

 

1. Is the shaft going all the way to the end of the cylinder causing them to spring a leak? Should I adjust the next one or put some washers behind the master cylinder to adjust the distance?

2. If I adjust it will the leak go away or have I already screwed another master cylinder

3. Can you buy rebuild kits and how to?

 

Such a pesky little thing to keep happening after such a big conversion but if I don’t work out what’s going on it’s going to be expensive to keep replacing MC’s.

[trav_555]

I'm not sure about your first 2 questions Luke, BUT

 

Mine is getting rebuilt/re-sealed before I put it in, Rebuild/seal kit costs 20 dollars :dance:

 

I hope you havent had it so it pushes in so far that it has broken something, have you tried unhooking it all and then pushing it in by hand then measuring up how far your pedal goes in? Also the rubber/metal stopper for the pedal is still intact yes?

 

Hope that helps :yes:

 

Travis

[LukeAE71]

Trav as I described above when the pedal hits the floor the shaft goes all the way in to the end of the cylinder. I checked this by pushing the pedal in by hand.

 

It is not being forced in and hitting the end but it is making it to the end. If it was hitting the end it would be a noticeable solid restriction which would stop the pedal going any further which I would notice.

 

Both of the units have been secondhand and I wonder whether due to lack of use they have gone to crap and when I start using them frequently they don't last.

 

I also think I have stuffed up.

 

Anyone else??? :dance:

[mikey_m]

I did the same on mine, the problem will not relate to the cut holes or strenght, there will be plenty.

 

I think you are right, the movement on the back hitting the spring will not be helping.

 

I had issues with a second hand one with enough pressure/leaks too. Leaked through a side thread, was not worth doing anyhtign with.

 

I got a NEW one from Repco for $60, and it has never had an issue yet. This might be your best bet.

[Felix]

I wonder if maybe the bore of the clutch cylinders have developed a lip on the inside (like in an engine piston bore), from in their previous application? If so, and you are forcing the piston in further, the seals will have a hard time keeping up.

 

A new clutch m/cyl would probably be the best bet. Maybe alter your pushrod length as you have stated, to ensure the piston doesn't bottom out.

[LukeAE71]

I wonder if maybe the bore of the clutch cylinders have developed a lip on the inside (like in an engine piston bore), from in their previous application? If so, and you are forcing the piston in further, the seals will have a hard time keeping up.

 

A new clutch m/cyl would probably be the best bet. Maybe alter your pushrod length as you have stated, to ensure the piston doesn't bottom out.

 

This happens on brake m/cs when you bleed them if you go too far past an old point they crap themselves.

 

Makes perfect sense what you are saying, I guess it is time for a new one and just adjust the piston back a little so it doesn't go in so far. I note that the piston does have an adjustment thread on it where it connects to the pedal, separate to the pedal adjustment item.

 

:dance: