Stuff in brake fluid?

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SirDan

SirDan

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my brake fluid looks dark and its got black crap floating in it. this is only in the front brake reservoir (the big one) Obviously this is an issue. But what is the issue do you think?

Heres the "history" of the brakes. 7? years ago my dad rebuilt one side of the suspension and put a new caliper, pads,rotor and rubber line on that side. The car sat for 5 years. 1-2 years ago i rebuilt the other side and put a new caliper on, pads,rotor and rubber line. I put a new rear rubber line on and new hard lines on the car as well and obviously added fresh fluid. Last year i put on a new booster, master cylinder, wheel cylinders, drums and rear pads. I must have bled half a gallon of fluid threw the lines and the pedal was still soft. drove the car around a bit, and now i have this fluid issue. Probably related.

So what should i check and do? I'm rather P.O.ed after replacing all that stuff and having issues still.

Yes i do know how to bleed brakes, done a few and never had issues. And yes the front calipers are on the correct sides with the bleeders at the topmost part of the caliper.

any help here is GREATLY appreciated!
 
It is obviously something deteriorating. Might be rusting metal tubing, might be hoses/ rubbers disintegrating, if it uses plastic pistons, they might be.....or just plain rust from the cast iron in the master and calipers. In other words, darn near anything inside there. I'd inspect, replace, rebuild anything that has not been in say, 5 years, flush out ALL fluid and replace, and then keep a wary eye on it.
 
That sounds like rubber in the brake fluid. Spongy brakes and dark fluid, I would check the flexible hoses. Do you see any possible leaks around the caliper pistons?
 
Replace hoses and bleed the crap out of it.

spongey could be air, or crap hoses. Don't think you have bakelite pistions in that year.
 
Mushy pedal after that much fluid bled through it makes me suspect contaminated brake fluid. Someone in the past may have goofed and put some oil in the master cylinder. I suggest changing the master cylinder, and rebuild the calipers and wheel cylinders. A real good clue of contamination is the rubber seal on the master cylinder cap. If it's deformed and enlarged where it doesn't fit right you have oil in your system. If that's the case for sure change your rubber hoses and proportioning valve also.
I've found this happens a lot when your oil is changed at a quick lube location. Those guys are rushed so much that sometimes they put the wrong fluid in the wrong places.
 
About brake fluid... If a container is opened and only a portion is used, The remainder is often left on a shelf for months or even years. Since the seal was broken the fluid can become contaminated and should not be used.

About new parts... New cast iron parts, including master cylinders and calipers, have a light oil coating applied to prevent rust. The oil will discolor the fluid but would not cause any other issues like soft pedal.

You could flush and pressure bleed until you have clean clear fluid all around but guess what ? as the linings wear the rubber cups and rings move across oily areas and pick up small amounts of oil again.
Since the fluid isn't circulated that oil and discoloration will remain in the caliper/ wheel cylinder and never be seen until next bleed.
Still, none of this will cause poor braking.

For the record... Replacing calipers should be both at the same time.
 
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