blazerdup

So I recently changed from a single bowl MC to a dual bowl MC. I put brand new brake lines on the car too as well as replacing the drums and shoes. The other hardware is only about two years old. So I have been driving the car for a few days with the new brake system. I had to replace the MC push rod to an adjustable one because the pedal was squishy. So when I was looking over the lines and checking the fluid level I noticed in the fluid in the rear resevoir was hazy and rusty looking. What in the world would cause this? The fluid level wasn't low either.

What gives?

Gun Jam

some sediments from the wheel cylinders maybe... If it bothers you extract most of it and replace with fresh fluid and see if it stays clear.

Although one would expect any old fluid to exit the system during the brake bleed process.

-Gun

blazerdup

Hmm, so should I be concerned about this? Should I replace the wheel cylinders? I swear I did that a little over two years ago. I did bleed the brakes a couple times and went through a ton of brake fluid. So for it to do that just stumps me....

Gun Jam

I wouldn't worry although there is no harm in extracting the fluid with something like a syringe.

If the brake cylinders are not leaking and you have good pedal stiffness your only real problem is some fluid thats not a 100% clear.

-Gun

blazerdup

hhmm ok, thanks. So it more than likely came from the wheel cylinders. Ok I feel a bit better now

KMatch

Be sure you used DOT3 and not 4 or 5, or at least none of those have been mixed at any point. I can't imagine mixing fluids would cause a color change but it WOULD lead to no brakes. I only bring this up because based on your description, there shouldn't be any reason for rust. If it IS rust, you either used some lines that need replacing or your fluid was contaminated at some point, likely with water. Brake fluid is hygroscopic - it absorbs water.

Starfury

DOT3 and DOT4 will mix just fine. It's DOT5 that you can't mix with either of those.

blazerdup

Thanks, all I used is DOT 3. Is it possible that there is too much pressure on the front wheel cylinders now that I converted to a dual bowl? Could it have damaged one of them? Do I need to use a proportioning valve now?

Gun Jam

Prop valves are typically used on a front disc rear drum setup they are used to offset the pressure allowing for equal braking load on both front and rear...it would for example, prevent the rear wheels from locking up well before the front wheels have reached their maximum braking threshold limit allowing one to adjust max threshold limit for both front and rear so all 4 wheels lock up at the same time.

If all you changed is your MC I dont believe you'll need a prop valve.

Nor do I believe you have damaged a SC. A damaged SC would show up as brake fluid leaking onto the inside of the wheel and loss of fluid from MC.

Extract some of the fluid using a syringe and hold it to the light is it just cloudy or are there rust pieces in it?

extract most of the fluid and replace with clean fluid it should stay clean.

-Gun

scootchu

My MC was rusting inside and sending cloudy rust colored fluid to each cylinder. I bled the system and it cleared up. Next time I bleed the brakes I will have to take note of the clarity and color.