87 GN - converted to vacuum brakes by previous owner (?). Brake pedal was "soft" - traveling nearly to the floor. Interestingly, the booster is larger than a N/A Regal - between 10-11" diameter (nearly touching the inner fenderwell). Never been able to build boost against the brakes at the track.
So...figured there must be air in the lines. So, I bought some soft rear shoes (Kirban) and 7/8" S10 wheel cylinders while I was at it. Bled, re-bled, still couldn't get the pedal to firm up.
Replace the master w/rebuilt for a N/A Regal - bench bled w/plugs until travel was nearly gone. Mounted MC on Booster - started car - firm pedal. Connected rear brakes - pedal still firm (not quite as much of course - but still good). Connected front brakes - pedal goes nearly to the floor.
Replaced cracked (although not really worn) front pads - re-bled (at master and calipers) - still soft.
Replaced combination valve w/new brass valve. Rebled whole system - still soft pedal.
Replaced Booster w/9" dual diaphragm (sp?) rebuilt (NAPA). Swapped pedal (appeared to be the PM pedal) with one from a Cutass. Pedal stiff and brake reaction slow - unable to lock brakes at all...seemed like too little assist from the booster.
Swapped MC w/rebuild from 78-82 carb/turbo regal (smaller bore).
Still hard pedal (yes, smaller bore won't help this - but worth a try)
Swapped back "mystery" booster - soft pedal again.
Swapped back larger bore MC (for more volume) - soft pedal.
Tried isolating front brakes - side to side - by blocking one side (passenger) at the combination valve - brake pedal was firm! Replaced rubber brake line and (eventually) the caliper (rebuilt) on passenger side - but still had soft pedal after bleeding.
On a hunch, I tried blocking the drivers front - firm pedal - here we go again...ugh!
So...if you've followed this post this far - I've replaced everything but the driver's caliper and rubber line (tonights project I guess) and the hard lines.
The car has 15-16" of vacuum - which seems a tad low (which would explain stiff pedal w/smaller booster maybe).
What am I missing? Anyone got a "good" PowerMaster (if such an animal exists)?????
So...figured there must be air in the lines. So, I bought some soft rear shoes (Kirban) and 7/8" S10 wheel cylinders while I was at it. Bled, re-bled, still couldn't get the pedal to firm up.
Replace the master w/rebuilt for a N/A Regal - bench bled w/plugs until travel was nearly gone. Mounted MC on Booster - started car - firm pedal. Connected rear brakes - pedal still firm (not quite as much of course - but still good). Connected front brakes - pedal goes nearly to the floor.
Replaced cracked (although not really worn) front pads - re-bled (at master and calipers) - still soft.
Replaced combination valve w/new brass valve. Rebled whole system - still soft pedal.
Replaced Booster w/9" dual diaphragm (sp?) rebuilt (NAPA). Swapped pedal (appeared to be the PM pedal) with one from a Cutass. Pedal stiff and brake reaction slow - unable to lock brakes at all...seemed like too little assist from the booster.
Swapped MC w/rebuild from 78-82 carb/turbo regal (smaller bore).
Still hard pedal (yes, smaller bore won't help this - but worth a try)
Swapped back "mystery" booster - soft pedal again.
Swapped back larger bore MC (for more volume) - soft pedal.
Tried isolating front brakes - side to side - by blocking one side (passenger) at the combination valve - brake pedal was firm! Replaced rubber brake line and (eventually) the caliper (rebuilt) on passenger side - but still had soft pedal after bleeding.
On a hunch, I tried blocking the drivers front - firm pedal - here we go again...ugh!
So...if you've followed this post this far - I've replaced everything but the driver's caliper and rubber line (tonights project I guess) and the hard lines.
The car has 15-16" of vacuum - which seems a tad low (which would explain stiff pedal w/smaller booster maybe).
What am I missing? Anyone got a "good" PowerMaster (if such an animal exists)?????
