Brake Fluid Flush

Reader Question

Hello Austin,

I recently acquired a 1993 ABS-equipped Chrysler Concorde that had never had the brake fluid flushed in its 13 years-old life – EVER. In light of that, I decided to have the system flushed as a better-late-than-never precaution at my local Firestone.

As they prepared to do the fluid flush, one front caliper was diagnosed as sticking shut (there had been a rubbing noise when the brake pedal was not depressed, so that mystery was solved). I therefore wound up having both front calipers replaced in addition to the fluid flush.

After the work was done, I checked the master cylinder and found that the fluid is not crystal clear as I expected. Instead, it is a darker, slightly transparent color – darker than the brake fluid in your picture at Brake Fluid Pictures

I took it back to the Firestone and they said that it will never be crystal clear due to the corrosion within the system that accumulated over the past 13 years. They tested the fluid with a strip, but it was not all the way near zero for moisture, so I held my ground and maintained that I was still not satisfied.

The guy offered to flush it again free of charge. But in your opinion, do you think that I caught them cutting corners? Do you think that they only bled the brakes to get the air pockets out rather than completely flushing the brake system to get all the dirt and scum out as I originally ordered?

Or is it possible that the system is so dirty after 13 years that it needs 2 or 3 flushes in a row? I’m not sure, but I expected to see better–looking fluid sitting in the main brake reservoir after a brake flush.

Thanks,
Tom

Hi Tom,

Great question! My first thought would be that you probably will not get your brake fluid reservoir to be pretty and clean like my picture after 13 years of rust and contamination etc. etc.

BUT, if they overhauled or replaced the two front calipers I would suspect that they SHOULD be able to get the fluid pretty darn close to the clean picture I have posted.

Most of the dirt and debris will be found in the master cylinder itself and then in the brake calipers and the wheel cylinders in the rear…if your car is equipped with rear drum brakes.

So, I would have them re-flush the system, which if they really do it like you are supposed to it will take them about 45 minutes to an hour…plus the bleed time if needed afterwards. We will sometimes open all the bleeder screws and allow gravity to suck out the brake fluid.

This will take an hour or two (and you have to periodically top off the brake fluid or you will get air in the lines) but we can do this while we work on other cars…and we bill you for a “flush” as we allow gravity to suck out the old fluid until the new fluid runs clear in the system. What a country we live in!!! hahahah

Having fluid that is free from moisture is more important than clear looking fluid…but I bet you were charged for a flush, so might as well have them re-flush it.

Please share this with your friends,
Austin Davis