302steve

1971 Fastback. Originally all non-power drums. I have converted fronts to SSBC discs still non-power, but the car does not want to stop.
I want to add a power brake booster.
I have an old booster from a 1973 Mach stashed in the garage.
Do I try to rebuild the old unit or buy a conversion kit?
Any suggestions as to brand of kits?

Gun Jam

are you running the dual master cylinder that came with the ssbc kit?
What size are the rotors?

It should not be too difficult to add a vac booster system to the Master Cylinder on the firewall.

I run SSBC on my 66 non assisted for the last 14 years I recently switched to an ultra high performance tire and even with the improved traction I still have no issue reaching the threshold brake limit quickly...But im running a possibly smaller 11 rotor and my car is 500+ lbs lighter... You might want to ask SSBC about the master cylinder and the vacuum booster they can probably provide some options.

302steve

I did not get a master with my kit. Only the front brake set up. I do have a dual rez master from my drum brakes. Would it be a different master and could that be why my brakes are so poor?

Gun Jam

Yes it could be...If the diameter of the MC is not matched to the Slave Cylinder you wont have the mechanical advantage you need to generate enough braking pressure.

This assumes a few things: 1) Master cylinders come in different diameters and or Slave Cylinders come in different diameters....I bet they do but I am not certain...this would be a good question for SSBC. If they are mis matched it could explain the excessive pedal force.

Can you push the pedal in hard enough to lock up the wheels at a safe speed say starting at 30mph? Don't let em skid... just hard enough to get a tire to momentary lock up then back off a bit...If you can't apply enough force to do this...yeah thats an issue.

-Gun

302steve

I cannot get the brakes to lock up. What you are saying makes sense. I will give SSBC a call.
Thanks

Mach428

Do yourself a big favor, IF you do need to purchase a power brake unit, buy the master cylinder with it alread installed as a matched set. I've seen SOO many people pull their hair out trying to get mismatched components to work together.

302steve

Good advice. A reman booster and master are a lot cheaper than the conversion kit. But I am barely a weekend mechanic, so I want to make it as easy as possible. I do want to do it myself.