Power booster issue
 

I have a 9" dual diaphragm booster & stock GM master cylinder powering my Baer 6S 14" front & Baer 12" rears. The brakes have been working perfectly until the last week or so.
It has started losing power assist randomly.
The engine has good vacuum. I have checked the check valve that snaps into the booster & it works fine. I'm fairly certain there are no vacuum leaks, and wouldn't think a vacuum leak would result in a random failure.
My question is whether a failed/ failing booster can do so randomly? Could 1 of the 2 diaphragms be bad?
I am happy to replace the booster, but hate to do so & find I have the same issue. It is the end of the season up here & it will be 5 or 6 months before I will know.
Anyone ever experienced something like this?

Thanks for any thoughts.


Bill

Hi Bill,

Did you ever get this figured out?

One customer was experiencing the same symptoms and turned out he was using a regular hose for the vac feed. Every so often it would suck closed.

Vince,

Sorry, I missed your question. I didn't. As I wanted to upgrade the stock master cylinder anyway, and was pulling the car apart for the winter, I just decided to ditch the booster altogether & just put a Hyraboost setup in it.
FWIW, I DID talk to a few power booster experts that said they had not heard of my intermittent problem. (I'm sure mine can't be the only time in history this has happened....)
I did inspect the supply hose & it was fine. Fuel rated, thick wall hose, no holes in it, even put a vacuum pump on it & it was fine. I'm sure there's an issue buried in the booster, but I don't see how it comes apart, and I guess I don't care enough to try to take it apart to find out.
I dunno, it's a mystery to me....


Bill