Hi

Noticed yesterday that my brakes did not work as it should.
When I pushed on the brake pedal there was "phssss" sound
down therewere the pedal is. And when using the brake initially
they worked fine, but just after a second or two they just "faded away"
and that "phssss" was heard.
The "phssss" sound only appeard in the phase when the pedal was
doing itīs movement, NOT when fully pressed, and NOT when resting in
the origin position

For me itīs not a typical scenario when the diaphragm leaks when the
noice can be heard instantly and the engine starts to "wobble" due to
extra air, wrong air / fuel mixture.
Is iot possible that it is JUST the O-ring on the master cylinder
piston rod that has to be replaced .

Sorry for my grammatic errors

Best Regards and take care


"Arken " from Sweden 1970 454" Chevelle Malibu SS

Home page : http://www.garaget.org/?car=76782


http://i38.tinypic.com/2enq7hd.jpg
http://i34.tinypic.com/vrzlz8.jpg

Nice looking car. That said, when you hear that hissing sound it means that your vacuum booster has failed. Time for a new one. I have no idea if anyone is "remaning" them. Maybe someone else in TC can answer that one.


The failure you speak of has nothing to do with the master cylinder.

Good luck!

Hi

Noticed yesterday that my brakes did not work as it should.
When I pushed on the brake pedal there was "phssss" sound
down therewere the pedal is. And when using the brake initially
they worked fine, but just after a second or two they just "faded away"
and that "phssss" was heard.
The "phssss" sound only appeard in the phase when the pedal was
doing itīs movement, NOT when fully pressed, and NOT when resting in
the origin position

For me itīs not a typical scenario when the diaphragm leaks when the
noice can be heard instantly and the engine starts to "wobble" due to
extra air, wrong air / fuel mixture.
Is iot possible that it is JUST the O-ring on the master cylinder
piston rod that has to be replaced .

Sorry for my grammatic errors

Best Regards and take care


"Arken " from Sweden 1970 454" Chevelle Malibu SS

Home page : http://www.garaget.org/?car=76782


http://i38.tinypic.com/2enq7hd.jpg
http://i34.tinypic.com/vrzlz8.jpg

Master would not cause the "PSSSS" Bad power booster, get a new one.

Hi and thanks. Will get another booster asap....

Went out to the garage frustrated that I didnt fixed the problem. Checked all the parts again and noticed an o-ring on the pushing piston, just when it´s entering the booster, looked a little thorn. Replaced it, smacked it all together, bleeded the brakes, and now it works just fine. Saved me the cost of a new booster, just an o-ring for 50 cents and some hours in the garage.:)

Dam !!! Good job...... you re persistent :D