philooo

I have had 2 brake fluid flush and last one by a professional and I still have mushy pedals from time to time, not as bad as before the pro-flush but still.

I was wondering if anyone had done a 'bench bleeding' of the master cylinder ?


My fluid is not boiling when I am coming back form hot laps, but the pedals doesn't feel progressive at all. it goes from a level of 0 to 5 with progressive grip, then it get mush and jump to 15, then it is progressive.

So right now I am braking really early because I really don't have a good feel on the brakes.

On the street, the feel is perfectly progressive.

I have PFC brake pads all around with stock rotors (27k street miles on them).

Macster

Can't imagine how the master cylinder could be bench bled. The device would have to be disconnected from the hydraulic lines which no matter how thoroughly you bleed the thing on the bench almost certainly you are guaranteed some air will be reintroduced when the cylinder is reinstalled and reconnected to its hydraulic lines.

Every car either used on the street or the track has its braking system successfully bled while the master cylinder remains in the car using either a pressure bleeder or the other technique.

Are all the underbody plastic panels/ducting present? If these are missing the brakes may not be receiving their proper allotment of cooling air and the brakes may simply be running hot.

Added: I watched a bit of the video. While it can be done it seems so unnecessary unless perhaps the master cylinder was new and replacing a bad one and bench bleeding gave the mechanic a bit more ability to work the cylinder around to remove those hard to remove air bubbles from the cylinder. But it you want to bench bleed your car's master cylinder...? Who knows? It may be just what the doctor ordered.

Sincerely,

Macster.

philooo

I indeed never heard of such thing on rennlist but as I was making a search I saw a couple miata or vette forum talking about it. I'll bleed the system again, this time trying to activate the abs pump with the durametric to get all the old fluid out, we'll see

mglobe

Just out of curiosity, what kind of brake fluid are you using? How sure are you that you are not boiling it? It's not something you would see, only feel.

ivangene

fluid?
pads?