Powermaster runs continuously only when hot

[NJMatt50]

Hello. My powermaster motor runs constantly only after I drive the car for about 15 minutes. Cold it seems to work fine. I just took out the check valve and cleaned it. Also replaced the pressure switch. Same thing. Any ideas?

 

[gsgnnut]

Time for a vacuum conversation. Probably bad accumulator but its just the tip of the iceberg.

 

[Chuck Leeper]

What Gs said^^
Change it before you wad it up....

 

[BEATAV8]

Could be internal seals in the master cylinder. Those you might be able to buy from Karps power brake service. Or it could be internal leakage in the pump. In which case that unit is pretty much done because new pump/motor assemblies are pretty tough to find.

 

[Steven Richards]

Replaced mine last year with new power booster, master cylinder and pedal from an 87' Monte Carlo. Works great!