vacum brake quest


New Member
Aug 9, 2005
I just completed the conversion to vaccum brakes bled the lines the pedal is very firm but the car does not stop. it slows but takes forever to stop? I also put in new master cylinder. Any ideas on where to go next? When in gear it barely holds any idea would be great. thanks
How did you provide vacuum to the booster and did you bench bleed the master cylinder before installation?
Sounds like you're not getting enough vacuum assist. Do you hear any vacuum leaks? Sometimes you can hear a constant hissing down by your brake pedal. Do you have a vacuum gauge? If you're running a race cam, you won't have enough engine vacuum for vacuum brakes.
yes I bench bled the master, and I purchased a new vaccum block for the manifold with fitting for the brakes.
First I would rebleed the brakes. I just did the changeover and bled the brakes enough to add a full pint of fluid. Works great and got air from all corners.
Also, you do have the check valve inserted into the booster, right? If you don't have a check valve or it is leaking, you will have no vacuum to assist you. I know it is a dumb question, but just another thing to check.
Just did this conversion on Saturday. Brakes are great.

=Advance Auto booster/mc for 86 non turbo regal
=vacuum block from cotton perf
=replaced vacuum hoses (non brake items)
=bled brakes (speed bleeders on front),bled rear by manual pumping
=drilled new hole 1.25" below old hole in brake pedal arm