At an autocross practice day yesterday, one of the tech guys asked when was the last time I changed the brake fluid. Well, I admitted that in the three months that I've owned the car I never had.

So today, I decided to give it a try. I have to admit first that I've never done this with any car before. My only experience with brake is just changing some disc pads and drum brakes many years ago. I think I got through the process OK and the pedal is nice and firm and the car still stops. The brake fluid that came out was a really nasty brown color. Since I have no idea when it was changed last, and it looked so bad, what kinds of problems may I be looking at from really old brake fluid?

Also, if it was really bad, is there any advantage to changing the fluid again in a month or two? How often do you folks replace your brake fluid?

 

i do it roughly every year, mostly because something breaks and i have to fix it anyway. some people do a flush after every event.

as for negative effects, the party line is that brake fluid attracts moisture which supposedly can cause rust inside your brake system. it also lowers the boiling temp of the fluid, which is mildly bad for street cars but very bad for track cars. debris also accumulates and can tear through seals in the m/c or caliper. i've had old m/c's go on me during bleeding because of this.

anyway if you got the flush done you can't do much more. just keep up with it.

 

Thanks. At least the brakes worked at today's autocross. I'll flush again next year.

 

Installing speed bleeders will greatly simplify brake bleeding:
http://www.speedbleeder.com/automobi...ions.htm#Mazda

 

if you are autocrossing regularly i'd do it every few events

if you run track days where you are hard on the brakes then i'd definitely do it right after the event, maybe right before as well

 

whats the fastest way to completly flush brake fluid? I know Im not supossed to let the master Cyl. get too low, so should i just bleed fill, bleed fill?

 

thats exactly what a flush is

fill and bleed, repeat

i recommend something like ATE super blue

its colored so you can tell when the old fluid is all out

it doesn't take long at all, but it does require a buddy