Brake sticks on 68 valiant

[Vali68]

I have a 2 door valiant with a slant6 and auto trans. It has a disk brake conversion on the front and drum brakes on the rear. I notice when I step on the brakes pedal, the brake pedal sticks and I have to put my foot behind it to make it come back up. What should I look at for issues?

Here is a picture of the master brake cylinder on the car.

 

[TrailBeast]

Does the fluid look good and clean?

 

[Vali68]

Yeah. The fluid is clean and looks fine. Not brand new, but it isn't bad.

 

[cudajim]

I had that problem with my 67 Barracuda. Turns out it was the booster. There's a special grease used which I got from a place in Sacramento, Ca. I think I have some left over. Where in Ca. are you?

 

[Vali68]

Riverside County. Actually Murrieta, CA.