green brake fluid... algae ?

[1 FMF]

what's the consensus on brake fluid algae?
went to flush the brakes on my 2006 gmc sierra since when i bought the truck i saw the master reservoir was dirty.
I ended up putting a new master with res. on it because i cannot buy just the plastic res. and the old one was so bad i could not clean it.
the old reservoir had dark green or blackish fluid, there is a dark green scum inside the entire res.
when i flushed the brakes i had green fluid coming out of each caliper.
When i pulled the res. off the original master while on the truck, i could see floaties and sediment in the ports of the master where the res. sat. When i disassembled the original master, there was a green slime coating inside on everything. It basically wiped off, and using brakecleen and alcohol cleaned up but there is a light green tinge on all the metal inside the master. can this be from algae, or is it just decomposed and broken down brake fluid?

 

[brandini]

right on both accounts.

Found that on a friend's truck as well, you should have seen the clutch fluid, looked like mercury.

 

[Falken]

Some brake lines have copper linings, saw some at school. Copper oxide is green.

Maybe this is the reason? Not 100% sure.

 

[scurvy]

I've used light amber brake fluid to flush Ate Super Blue. When used straight, ASB can stain the reservoir and brake lines blue that leaches into the next fluid.

Brake fluid dye, algae or copper/copper-nickel alloy brake lines oxidizing could be a culprit.

 

[wirelessF]

You are not the only one. I had the same issue when I bought my 02 Chevy Silverado couple months ago. I went with a new master cylinder, pressure bleeder and 1 gallon of brake fluid to flush the system.

I also wonder if that could affect the ABS unit?

 

[artificialist]

I am sure it is copper. Many repair shops have a test strip that you dip in the brake fluid, and it tests for copper contamination.

I have seen a few brake systems with a fungal green color, but dirt brown is more common.

 

[1 FMF]

the thing i disagree with on the copper is the plastic reservoir on the master cylinder has a green scum all throughout it and i doubt that is copper, and i can't see how copper from the brake lines can make it's way upward through the master cylinder and into the reservoir

 

[user52165]

Originally Posted By: 1 FMF
the thing i disagree with on the copper is the plastic reservoir on the master cylinder has a green scum all throughout it and i doubt that is copper, and i can't see how copper from the brake lines can make it's way upward through the master cylinder and into the reservoir


Very easy - check out migration

 

[wiswind]

I'm no expert, but I don't expect that there would be THAT much copper migration from the system into the fluid.
The brake lines are STEEL as copper will not hold up to the pressure.....(so don't use copper tubing to replace brake lines).
However, I'm not saying that there is NO copper in the system....in fact they use copper washers in the few brake systems that I have worked on....and it has already been mentioned that there may be copper lining in some brake lines.

My guess is, in this case, it is algae.
The reason is that it would not be likely that the fluid would dissolve THAT much copper in the system.
However, that is just my (unqualified) guess.

Brake fluid attracts/holds moisture, which is why they keep the system sealed as much as possible.
Also, they say to use ONLY fluid from a freshly opened container of brake fluid.
They say NOT to use fluid from a container that has been opened a long time ago....and left sitting around on a shelf.
The moisture can help create a place for the algae to grow, as well as cause corrosion in the system.
Also, moisture will greatly lower the boiling point of the brake fluid.....which will cause a "air" or vapor pocket in the system (at the wheel)....causing loss of braking power (just like a air bubble in the brake line).

I like to flush the brake fluid every other year at each wheel.
Again, that is just my own over-maintenance practice.

 

[Tempest]

Could be blue racing fluid. It stains anything clear a color like that.

 

[GMorg]

It's not algae!

Algae have an absolute requirement for light. They are microscopic, single cellular plants.

Both nickel and copper salts can be green. You are likely seeing copper.

 

[Garak]

Originally Posted By: GMorg
It's not algae!


One would think that green chlorophyll wouldn't do well in a sealed, opaque brake system.

 

[gomes512]

It's a hygroscopic fluid after all, likely contained a good deal of moisture and accelerated corrosion on the system. GMorg is right on with the green salts he described.

Not to mention the lack of light deal. Assuming this is a glycol based fluid, bacteria would be out of the equation also since most glycol ethers have biocidal properties. Diethylene glycol monomethyl ether and triethylene glycol monoethyl along with a few others are good examples.