powermaster switch or cylinder?

[Drewster]

my brakes are cycling the PM motor every 3 sec or shorter. sometimes its one right after the other.

does this sound like a failing pressure switch or a leaking down master cylinder?


brake pedal is firm at all times (as firm as they have always been anyway). i have replaced the accumulator ball about 3-4 yrs ago.

andrew

 

[Mac in SD]

Drewster, I just changed out my master cylinder for that reason. My motor would cycle almost continuously on first startup, and then would cycle every time I braked. Anyway, I replaced it with a "suspected good" MC (reusing my old accum ball, pump motor, and switch), and it now works perfectly. So you could either rebuild the MC or find a low mileage one and swap it out.

Don't be surprised to find brake fluid on the actuating rod from your brake pedal. Talk about leaking!!

OTOH, it's alot easier to swap out a switch to see if that's the culprit before going through the rest of the PITA of doing the MC.
HTH.

 

[Drewster]

i dont think it is constantly running. just on for 2sec off for 1sec. and variations in between. sometimes fine.

i think i'll start at the switch.

thanks for the info mac

ill also check for leaks,and cycles without brakes applied

andrew