otis_lee

Any help would be appreciated. I've been working on a 1968 mustang coupe with 351w for a couple of years now. It has 4 wheel drum brakes without a power booster. I literally have to stand on the brakes for them to work well. I am wanting to make this car safer without throwing a lot of green at it. Keep in mind that the brakes work good...I just have to put a lot of muscle into it. Would keeping the 4 wheel drum brakes and just adding a power booster make a big difference?... or is that a stupid idea? Is front disk brakes the only way to go? I would like to keep it simple and add only a booster if it would make a big difference.
Thanks a lot.

JMD

IN SPITE of what some think, drum brakes CAN work just fine so long as a person is not literally on the "road race" circuit....

I am running an 8" booster on my 55 Lincoln with drums, it stops BETTER than really, really, good...

And stopped is stopped....



It sounds as if you MIGHT have a M/C with too large a bore for manual brakes...

The booster and m/c in the pic were quite a bit less than $200.00 combined.

otis_lee

what m-c bore is a good option for my application? There are a lot of m-c/booster combo options on ebay. Will any of these work as long as they fit my year? They all say that the combo is for use with a front disc system. Does this make a difference? Thanks for your reply.

JMD

I don't know the size of your wheel cylinders, this is a variable that can effect what is right, but I would be fairly confident with a 1" bore for power drum brakes.

That is the bore I used on the Lincoln, the pedal is hard but workable without power assist, but it works easy and very well with power assist.

My guess is that the bore of the M/c you have now is probably right, hard but functional with no assist, should translate nicely to power.

I am almost thinking you might have a power m/c in by mistake now.

Aside from the possible bore differences, manual m/c's and power m/c's differ in that a manual m/c will have a deep hole to hold the push rod, and a power m/c will have a very shallow pushrod hole.

Aftermarket m/cs often employ an adapter so that a single m/c can be used either way.

I used a "dedicated" power (shallow well) m/c for my swap.

otis_lee

all extremely helpful information. thank you. when you say you bet I have a power master cylinder... you mean that they might have meant to install a manual one, but used a power accidentally? There is absolutely no booster in place right now. Regardless of what you meant... the mc / power booster combos on ebay will probably be paired corectly, right?
thanks again.

JMD

Should be right, assuming you find one for 4 wheel drum....

A disk m/c would probably work just fine with the addition of 10 psi RPVs, (residual pressure valves).

I used a "disk" m/c and added RPVs, you can see them in my picture above, they are the little red things on the descending brake lines.