Brakes failed. Master cyl?

[zavikan]

Revived 8 year sleeping car. Couldn't change brake fluid on site...it's pretty ugly dark brown....

Pedal went squishing to the floor after 40 minutes of driving. No leak anywhere.

Just a master cyl yes?


So...unbolt old one....bolt on new one....bleed brakes.....smile?

[theflystyle]

Before jumping to a mechanical issue you may want to spend a few quid and just flush the brake fluid and check the condition of the calipers/lines.

[1986nate]

Originally Posted by zavikan

Revived 8 year sleeping car. Couldn't change brake fluid on site...it's pretty ugly dark brown....

Pedal went squishing to the floor after 40 minutes of driving. No leak anywhere.

Just a master cyl yes?


So...unbolt old one....bolt on new one....bleed brakes.....smile?

If the brake fluid wasn't change when it went away, and then sat for that long, it likely developed a layer of rust on the master piston. Then, when it was moved, the seal that ensure when you push the brakes, pushes the fluid ripped/tore slightly so the brake fluid just goes back around it. There won't be visible leaks or anything as it still stays within the master. Had this happen a few times on cars we changed a brake line and since the brake pedal never sees the floor, once it's compressed all the way, it hits points it normally doesn't and you can't bleed the brakes.

So, try bleeding the brakes, but if it proves not helping, don't just assume you're bleeding them wrong. The master may in fact be bad.