DJ99

I flushed the brake fluid the other day and accidentally ran the reservoir dry. I re-bleed and the pedal is firm but now I have a squeak that is coming from the master cylinder when I push the pedal. It sounds like there is still air in there and causing a rubber on metal squeaking sound. Anyone ever have this problem and know how to fix it?

terbiumactivated

I see what you're saying now you were flushing the system. Are you sure it's not the pedal mechanism itself? Perhaps another member can chime in here but it could be possible that running it till dry effected the MC internals. There's a plunger mechanism in there and it's possible if it overextended it changed from where it was before it was run dry.

DJ99

I did some more research and found that ATE 200 brake fluid that I was using can cause the master cylinder to squeak. So I flushed the brakes again, for the 10th time, using Motul RBF600 and the squeak is gone.

From what I found ATE 200 has a very low viscosity. So I guess there was just not enough lubrication to keep it from squeaking.

terbiumactivated

I use Motul RBF as well

STLPCA

FWIW I used ATE 200 in 3 different Porsches during a period of 15 years without any issues. 1000s of other P car owners have had the same trouble free experiences.

terbiumactivated

No doubt it could be absolute coincidence I just like Motul products, I noticed you can get their oil now online via Walmart I am going to go back to buying it.