Help Mushy pedal

[res1vw21]

Well I know it's not an E but I did a brake job on a '65 Newport for a guy and I can't figure out what I did wrong.

I switched to a dual pot master and used a prop valve from a drum brake dart.

The Newport has all brand new lines and all brand new hardware. Everything is new!

I had some binding issues with the shoes but got it all straightened out so now the only problem is the pedal is mushy. It goes to the floor.

I bench bled the master twice, and then bled the wheel cylinders in order of rr lr rf lf.

I suppose my question is do I have a bad master? The master is a brand new rebestious unit. The pedal doesn't pump up either.


The car is a power brake all drum car.

Any thoughts? I have another master on order but it's gonna be 5 days and I don't want this car in my driveway any longer.

 

[burntorange70]

Is it an all new master or a new "rebuilt" one? If it is a remanufactured one it could very well be the problem.

Only other thing I could think to check would be the adjusters for the shoes may need adjusted.

 

[res1vw21]

It's new so.... I don't know I am about ready to have it towed off.

 

[burntorange70]

It's new so.... I don't know I am about ready to have it towed off.

I here ya. Some times working on old cars can be a PITA!

Good luck.. Hope you get it figured out for the guy.

 

[BIGSHCLUNK]

Sure you dont have any air in the lines?? It happens sometimes when allot of components get switched. I went through he!! w an olds years ago!

 

[res1vw21]

Well I used an over sized line from the master to the front system by accident. I took it to my buddy who is a mechanic and he fixed it for me.

 

[Flying Grape]

There could be a few things. The one I would suspect to be the most likely problem would be the Master Cylinder. Did you check for bore size? The smaller the bore size = more pressure and can lead to a mushy pedal. If you have too large a bore size the pedal can feel rock hard and a large amount of foot pressure will be neede to stop the vehicle. The second is hard to understand but very likely. Check very closely to see if the new pads are flat up against the rotor. It only takes a little mis alignment of the pad to make the pedal feel mushy. Pull the pads off and see where the rotor has been rubbing them, it should be all the way accross. If not see if the pads are binding on the caliper. the pads plate could need some tweeking or you may have the wrong pads all together. The third could be the proportioning valve. For a test, remove it and join the lines without it.
If the pedal is hard you've found the problem. Buy an aftermarket adjustable proportioning valve and install. do some brake test in some dirt to see if the rear is coming on too soon.

Have fun

 

[Flying Grape]

Re read your post. 4 wheel drums? My money is on the Master bore size.