contaminated brake fluid -- need help!!

[sky jumper]

2001 Blazer. rear pads were frozen in the caliper bracket (they didn't fit, and whoever installed them just hammered them in). so for several years the rear calipers were not operational.

upon replacing the pads and bleeding the brakes, dark green slime came out of the rear bleeder screws. a few pumps and it ran clear.

I then proceeded with a full brake fluid flush. but 3 months later all the fluid turned green, even in the master cylinder. so I flushed again, this time with about a gallon of brake fluid. now 2 months later the fluid is dark green again, and there's a slimy green coating covering the inside of the master cyl reservoir.

what should be my next move?

can I drain the master cyl and spray some brake cleaner in there to clean up the insides, and then flush the system again with 2+ gallons??

 

[HardbodyLoyalist]

I can think of only two possibilities:

1. Algae is growing in the system, which seems unlikely given the inherent lack of light.

2. The fluid is attacking a copper-based component, possibly a brass sealing washer.

Exactly what type of fluid are you using?

Does you manual call for DOT3?

Has the system ever been upgraded to DOT4 or (gulp) DOT5?

 

[sky jumper]

to my knowledge it has only seen DOT3.

 

[falconman]

Don't use brake cleaner inside the hydraulic part of the brake system. It's bad for the seals. You can try flushing the system again but if the problem persists, you may have to replace the master cylender and calipers, etc.

 

[ProfPS]

Bump-

Does anyone know of a chemical/antibiotic to add to brake fluid to kill algae?

 

[defektes]

whatever you do, dont mix chlorine in there, I have heard that causes small explosions.

 

[VicL]

Personally I can't believe its algae. First, there's no sunlight in there. Second, its a toxic mess of chemicals. Nothing for algae to live on. Third, the heat from the brakes would kill it.

Probably more of a chemical reaction to metals or seals. Id'be more inclined to rebuild the calipers given the history of the orginal problem.

 

[Scienceman]

yea

 

[Trav]

I know diesel fuel can support troublesome bacteria colonies and from what i read glycol based brake brake fluid can also.Apparently these are more common than one would think,Dot 4 and 5.1 (not 5.0 which is Silicone) contains more borate ester to combat bacterial growth.

I would first flush the whole system with denatured or isopropyl alcohol immediately followed by a couple of complete DOT 4 flushes,make sure to flush the alcohol out.


http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B7GVY-4H74MF7-1&_user=10&_coverDate=11%2F18%2F2005&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1196886651&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1712eead1744b3246ca8b00dd1d07063

 

[Kestas]

There should be no problem with algae in the system. Besides the lack of light mentioned above, the copper present in the system acts as a natural and strongly effective biocide.

 

[labman]

I am not sure any amount of flushing with anything would remove yuck from the annular gap between the caliper pistons and caliper. I would remove the master cylinder and all the calipers. Then flush the lines with methanol, air, and finally brake fluid. Replace the MC and calipers with rebuilt ones.

If the MC reservoir is the translucent plastic, enough light might get in to support algae. No matter how tough the conditions, something will manage to live there.