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Clutch Master Cylinder problem?!?

cyberbackpacker

NAXJA Forum User
Here is my dilemma...

I searched but did not find anyone having a similar problem.

Periodically, I "lose" my clutch pedal. It will still engage/disengage but the pedal drops all the way to the floor before it gives any resistance, and I only have maybe 1/2" to 1" of travel to pop it into and out of gear. However, the pedal always returns to its starting position (it just does not have resistance until it gets to within that 1" or 1/2" to the floor).

However, this will correct itself randomly and I will get full pressure from the pedal at the top of the range where I am supposed to. It kind of oscillates between normal and "weird".

I have not been able to discern any pattern to when the pedal "drops out" and when it performs as it should.

The clutch itself is fine, no slippage, fluids good, etc. and as said, even when the pedal drops to the floor I can still engage/disengage but the working motion is severely decreased.

Pumping the clutch does not cause a change in the pedal.

I am thinking it may be the master cylinder. Maybe the seals are worn out, allowing a bit of seapage preventing the plunger from returning to starting position? Maybe the plunger itself is bad? The spring?

Opinions? If you agree and think it is the master cylinder, should I get the rebuild kit and go that route, or replace the master cylinder? Rebuild kit is a 1/4 of the price of a new MC. Will the rebuilt MC last?

One last thing to consider. Coincidence or not, I don't know, but the junction box for the fuse box right below the MC in the engine bay developed a crack in it, and with the recent Cali rains flooded the rig something fierce. I patched the crack with silicon. Don't think it is related (no loss of fluid or signs of leaks) but I noticed them both about the same time. So it could be coincidence, but just thought I would throw that out there too.

Thanks in advance for the help. This has me and a few buddies of mine at a loss as to what the problem really can be. Thanks.

BTW it is an AX15 tranny.

-Kevin
cyberbackpacker
 
sounds like internal leak at the master. brake fluid gets past the seal inside the master and reduces the effective volume of the hydraulic system. you know there is a little plunger inside the master and when it is old and worn the edges of the seal don't hold and fluid gets past.

in the past I have replaced the master with a rebuild and also replaced the slave and connecting hose at the same time. it can be a pain to bleed once the sytem is opened (to replace the master only) and the slave is probably old as well so most recommend replacing the entire system

discolored or brown fluid in the resovoir but no volume loss will indicate internal master leak

good luck
 
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