Brake Booster For 1971 Plymouth Duster

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KP

KP

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After doing about 85mph the other week then blowing by the road I wanted to turn on because I could not slow my Plymouth down enough with the stock non-power brake. I decided to see if I could find a so called “power brake” booster at the Carlisle Chrysler Nationals the other week.

I found what appears to be a nice used unit and had the person selling it test it on his vehicle by disconnecting the vacuum hose to his a connecting it to the unit he was selling.

The question I have, is there anything I need to do other then bolt it in place and run a vacuum hose from my intake to it?

The car has disc brakes on the front off of a 1973 Charger and a Dana 60 with the large drums on the rear.

Someone was telling me I may have to install a valve of some kind???
 
With front disks and rear drums, you most likely need an adjustable proportioning valve. You plumb it in series in the rear brake line, after the "imbalance warning valve" if you still have that. You adjust the knob until the fronts skid before the rears on a wet road or pea gravel. Cost $25 for Chinese to $80 for name brand. I use Chinese (ebay) and looks like from the same factory.

Above is independent of whether you use a power booster or not, as cudajim said. I understand that most factory systems used a slightly smaller MC piston with power brakes in A-bodies. I think that is because of the lever ratio added by the stand-off brackets. But there are many factors in selecting MC and wheel cylinder bores, including how strong your leg is. Also, a booster won't help much if you have a radical cam and not a steady and acceptable vacuum at idle.
 
I'd add the booster and make sure yoiur master has a smaller bore I'd go with a 1 Inch bore. the adjustable would only benefit you if you are having problems with the rear brakes locking up before the front brakes lock up. Skip the adjustable and instal the booster and a small bore master.
 
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