We have changed the Clutch Slave 5 times in the last 2 months. They keep busting/leaking under pressure. We have inspected and removed the Master Cylinder, changed the flex line....but each Slave will work for only a couple of weeks and then they bust and leak. WHAT THE HECK is going on...???

It is not the pivot ball inside the tranny (I don't think).
We have adjusted the tension and pedal travel.
We have bled the lines correctly.

My friends...what the HECk is going on with this 1985, GSLSE....???

Are we doing something wrong? NEED I take it to a shop? Need I drop the tranny and take a look inside? I'm going crazy here...please help.

 

What kind of clutch are you running? I know some guys go through slave cylinders when they have a very aggressive pressure plate (hard pedal)

 

No, it's not a racer...just an everyday driver. It's stock clutch and stock slave. I just don't know anymore.....

 

Try an oem slave cyl?

Where are you getting these?

 

Mazdatrix...they are OEM.

 

What type of fluid are you using?

 

uh oHHHHH.....what's that? Dot 3 right? Should it BE SPECIAL Mazda fluid???

 

no dot 3 is ok. so does it have a very stiff pedal? It should be very easy to depress being hydrolic. If it is hard to depress then this why you are having failures. also need to check that you have the correct pushrod in the slave. too short of a push rod will cause failure due to over extension of the piston. with the new unit installed before bleeding, check the free play should be very minimual. that slave only moves about 2 and a half inches if I remember correctly. If it is over extending this will cause premature failure.
Just a thought

 

It failed/leaked with a stiff pedal so we adjusted to make it "softer" and the new slave failed....just the same. I'm going broke replacing this thing.

1. could it be the clutch fork?
2. could it be something internal in tranny?
3. it is time to change out the pressure plate and flywheel?

 

You should be able to just get the rebuild kit. Its just the rubber grommet that is incable of holding the pressure. Should save you some money. I think you have a non-stock pressure plate though.

 

Thanks brother....I'll look into that. Wish me luck.

 

Definitely go with a rebuild kit. It's just a cup seal, the bore should still be fine, no sense in buying a whole new assembly. I've has similar issues with other cars, and could never find the problem. Good luck.

 

The funny thing is....this old slave worked GREAT for many many years. Then it leaked from old age. Now, the new ones are just breaking left and right.

 

Maybe Mazda "improved" their design since the original for the car. Perhaps different material for the cup seal, or a poor fit between the seal and bore. Can you tell if the alignment of the push rod is straight, not cocked to one side? Not sure how, or if it would matter, but maybe the rod is sitting crooked and is pushing the seal and carrier crooked in the bore and allowing it to leak/blow by. It's a tight fit of course, so I'm not even sure if that is possible. Also, the length may not be correct. Has the fork ever been changed that you know if? Maybe Mazda "improved" something else and the rod length is too long allowing it to sweep further into the bore of the cylinder than is intended by original design. Otherwise, I can think of nothing else that might cause a problem like this.

 

This is just a theory I'm putting out there... but is it possible that you've got the MASTER cylinder pushrod set up for too much travel, so that you end up still pushing more pressure into the system even though the slave is already at the limit of travel, rather than reaching the end stop?

If the master still has travel left even though the slave has the fork and clutch all the way "out," and you're still pushing on the pedal, then the pressure in the system will continue to increase after max travel is achieved. Whether or not this could build enough pressure to blow out a seal, I don't know (seems like it shouldn't), but it's something to consider.

 

Yeah...we've got that 3 inch thick shop manual for the RX7 and we've looked at all the specs and have made all the recommended adjustments. It's just sooooo bizarre.

 

?

The FSM for the first-gen is like a half-inch thick...

 

Sounds like over stroking, contaminants, or too stiff of a pressure plate spring set. Or bad slaves?

I've using an over the counter reman slave and master and they work great.


How did you adjust it to "make it softer." The only adjustments are there to take up lash in the pedal to master connection. It should have a small amount of lash, but not be snug. If it's snug, then you could be over stroking.

Pedal firmness is directly corrilated to the pressure plate finger tension.

 

Have you seen the blue one? It's a good 2-3 inches thick...it's not Haynes or Chiltons. I got it from Mazdatrix years ago.

 

My original Mazda book is sort of a kermit green. I believe they changed colors every year.

 

Something else to keep in mind. The Clutch Pedal stop is a flimsy piece of metal with a rubber bumper on it.

I was looking at mine while installing a brake booster and noticed it was bent toward the floor a good 1/2" which could cause some over stroking problems.