I was forced into trans work by the wonderful 5th gear syncro. While I was in the I decided to replace the clutch with an act 6P. Since the swap I have been experiencing fade to fail when hot. I have since replaced the slave and the lines with braided ones, and have bled the system 5 times. Still the same issue. Fine until the car is hot and then pedal to the floor with no grab. Cool her down and she is all better. So I have thought of the bioling fluid, and the master. Before I start ripping the car apart yet again. Any ideas of something else or something stupid I may have done here?

 

Well, you replaced the slave, so it may be that the clutch master cylinder is leaking. Bleeding the system is simple enough, so I doubt it is air in the lines anymore. It is unlikely to be related to any heat issue. Leaks in the master cylinder can be kind of quirky, so it may just be coincidence it is only happening after warm-up.

 

Check under the dash where the clutch pedal rod contacts the master cylinder. If that is leaking or has signs of moisture then that is probably your problem and the master cylinder needs to be replaced. There are rebuild kits available however I do not recommend going that route as they are not always reliable (I have been through a few rebuilt masters). I would call up Ray Crowe at Malloy Mazda, 888 533 3400. He can get you a new master for a good price... I just installed mine today

 

I had one sitting around. I did inspect and there were no leaks. I bled a quick few times just to check and the fuild looks like it was burnt. I will change the master, but te fluid has been in the car for about 10 miles of actual driving and I swear it is as if it is breaking down due to a heat condition. And I know how crazy it sounds seeing as dot 3 should break down at like 410 degrees. There is almost a metalic look to the fluid. My breaks are a ok. I wil post what I find after changing the master and taking her for a ride. But if anyone has ever had a heat related issue please chirp in. I am leaning now toward replacing both and a full fluid drop as I do't like what I have seen.

 

Moral of this story. Don't think to much and keep it simple stupid. Changed master and everything was fine. I am not certain why the fluid looked so bad drained it and bled to be safe. Took a nice long drive bled again and even the fluid looks good. No obvious leak but it must have been there.

 

Glad you got it fixed!!