Master or Booster?Help!

[Railing68]

The Pedal doesn't feel super firm in the initial couple of inches when the car is running and still getting a hiss, but brakes will lock it just seems to take fair amount of effort. I am thinking about switching boosters due to inconsistent pedal feel. Is this the common problem with vac assist? Would a dual diaphram booster be a better option, and how much does the diameter effect assistance? I road tested and seasoned pads in, it got considerably better but I am not 100% satisfied with the inconsistent feel. Also the cover to the master is leaking and I wonder if this is partially due to the angle of mounting from the booster. I don't know if the MC original orientation was level I presume it was. Any suggestions would be greatly appreciated, SS

[fuzzyonion]

I guess this is a little late.

The OE booster/master was not level, and the rear resivoir with drum brakes was to be filled 1/4-1/2" from the top. Front resivoir with disc brakes- 1/16"-1/8" from top. This might help with the leak, or the cap and gasket might be a poor fit.

As far as the other problem I don't know, but you could do a vacuum pump test on the booster to see if the hiss is caused by a leak. The hiss could/might just be caused by a partial obstruction to the rear of the booster.

[cad]

My stock style master cylinder leaks a little on acceleration. It helped a little to replace the cap and gasket, but it still leaks. Which is why I posted a request in this forum yesterday for help determining a newer style master we could safely use with stock pedal and booster.
https://www.pro-touring.com/forum/sh...ad.php?t=11067

[mike67cam]

I had an 8” dual diaphragm booster on my 67 with a Baer track front kit and touring rear. The engine was making around 15.5” of vacuum. I was never happy with the feel of the brakes with this setup. It took more pedal effort than I liked. I probably could have benefited from the use of an external vacuum pump.

Based on the positive experiences of some on the board, I am trying a hydraboost setup. The car isn’t back together yet so I can’t give you a comparison between the two.

[68firehawk]

Mastercylinders are much cheaper then getting a new booster. Every mussel car i've ever owned had a slightly leaky mastercylinder. It probably has something to do with the quality of some of the massed produced aftermaket parts. If a new booster is required I would seriously consider forking out some extra dough for a Hydraboost system.

My 2 cents anyway

Jacob