Stiff brake pedal

[Will_H#24]

I just purchased a 69 Dart that has an after market power brake booster and Master cylinder. I can barely get the brakes to apply. Could they have put a booster for disc brakes instead of drum on by mistake? I previously had an 64 Impala with power drum brakes and I know they were way easier to push than this Dart.

 

[halifaxhops]

Prob just needs the pedal rod adjusted properly.

 

[clementine]

The benefits of drum brakes are that there is little to no drag in their resting state.

Make sure they turn freely. When car is on jack stands, they should spin with little to no drag.

If no drag then refer to post #2

If rod is correct then I like to give em a good bleed.

If problem persists after bleeding then consider the master isn’t correct.

When it’s up on stands take pictures and measure drums.

Post pictures of shoe orientation and innards as well as master cylinder for best results.

If the proportioning valve looks new, please include pictures of that.

I bet someone will spot your issue.

This will be the fastest way.

$0.02

 

[Professor Fate]

Stiff pedal, no brakes?
Make sure the booster is hooked up to manifold vacuum, and the check valve is operating properly.
Also, too much cam will make your manifold vacuum insufficient to correctly operate the brakes.
I won't get into what I think of some of those generic power brake kits that are just a hodgepodge of oddball parts...

 

[Bewy]

Disc brakes require MORE line pressure; so if it was a disc brake booster, the pedal pressure would be less.

As said above, check for enough man vacuum & hose routing. Also check the check valve at the booster [ hose plugs into it ].

 

[Will_H#24]

My mechanic told me there was no check valve in the vacuum line. He installed one and now it's a little better but still not as good as my old Impala was. He also bled and adjusted the brakes.