Something strange happened to my new clutch fluid, I have a theory but would like everyones input Options

[enderswift]

Hey everyone heres the backstory:

upon taking my 99gt our of winter storage, I gave it the once over to prepare for the thousands upon thousand of miles i was going to rack up this summer. I changed the oil, checked all the fluids/filters/plugs ect and everything seemed to have held up very well. The car ran like new
From there i drove the car around all day and there were no issues whatsoever (even after several light thrashings on a twisty road in my area). The following day I was coming back from my friends house and my clutch pedal stuck to the floor. uh oh there goes my slave cylinder, or so i thought. It ended up being my clutch master. I changed both. I also bled the whole system about 4 times thoughout the the whole troubleshooting process. In the end the celi swapped gears effortlessly again

on to my question:

the fluid i filled the system with was DOT III CLEAR fluid (as stated on the master cyl cap). now however, this clear fluid has turned a fantastic shade of brown


compare this with my brake master cylinder where i used the same brand around the same time i did my clutch ( i was on a roll)



nice and clear

so why would the fluid in my clutch system turn brown, while the fluid in my brakes stayed looking like new?
at first i thought that it may have been some gunk inside the lines that has since broken up, but that doesnt make sense since i bled the system FOUR times. should be as clean as it gets in there

could it possibly be that the master and slave cylinders are wearing in, thus dirtying up the fluid a bit?

input and opinions are appreciated

-Luke

[hurley97]

The black specs can only be bits of the rubber from the clutch hydraulic system (unless something from outside got in the system of course). There really isn't much else it could be besides the seals in the master cylinder or the rubber on the inside of the rubber line. The clutch hydraulic system is very simple and there isn't much to it, I'm sure you are well aware having replaced both the master and slave cylinders, but it goes master cylinder-->hard line-->rubber line-->hard line-->slave cylinder... that's it. Most likely its the cheap seals inside the autozone master cylinder. The only other thing it could be is the brake fluid you used is more corrosive to the rubber things in the system than what was in it last, which will also cause problems later, but as you said you used the same fluid in the brake system and that's just fine.

This post has been edited by hurley97: Jul 26, 2009 - 5:02 PM

[enderswift]

The black specs can only be bits of the rubber from the clutch hydraulic system (unless something from outside got in the system of course). There really isn't much else it could be besides the seals in the master cylinder or the rubber on the inside of the rubber line. The clutch hydraulic system is very simple and there isn't much to it, I'm sure you are well aware having replaced both the master and slave cylinders, but it goes master cylinder-->hard line-->rubber line-->hard line-->slave cylinder... that's it. Most likely its the cheap seals inside the autozone master cylinder. The only other thing it could be is the brake fluid you used is more corrosive to the rubber things in the system than what was in it last, which will also cause problems later, but as you said you used the same fluid in the brake system and that's just fine.

haha seriously, there is only so much that can go wrong in a system like this. well, I decided to bleed the whole thing all over again and you would not believe the gunk that came out, imagine the look of fine steel shavings in a blown engines oil, only black. If thats the result of piston seal deterioration then i want my money back; cuz that is not gonna last more than a few months at this rate. Cant wait to lose control of my clutch making a left turn in a busy intersection . You know I was suspicious of the fluid too, but going with the non toyota parts made me spring for the highest grade DOT III valvoline has to offer. Id imagine any defective/overagressive fluid would cause enough havoc for me to hear about it on the news by now. My new theory takes into account my original suspicions and what people have suggested thus far; its that the autozone parts have to go through a break-in period where the pistons wear themselves into the cylinder to ensure a perfect seal. maybe they make em a tad too big for this exact reason. I was otherwise very impressed with the build quality, from the casting of the metal to the quality of all the plastic bits. Either way, there is fresh fluid in there now, and im going to keep a close eye on things and post the results. Maybe someone will run into the same issue one day.

moral of the story: always, always buy OEM parts.

thanks to everyone who chimed in and offered their opinion. this is why 6gc rocks.

-Luke

This post has been edited by enderswift: Jul 26, 2009 - 7:04 PM