mushy brake pedal

[ksurfer2]

My 64 dodge has a VERY mushy brake pedal. I have manual brakes, wilwood disc brakes all around. No squeaks or squeals out of the brakes, car runs straight under braking, stopping power is marginal, at best. I have bled the brakes, fluid is fresh and clean, no air pockets. No leaks. Attached is a pic of the master cylinder. What should I check?

 

[Ron H]

Assume the master was nicely bench bled?

 

[Don Frelier]

It may improve with use.
Are the bleeders at the highest point?

 

[Ron H]

Curious, did the master come with you kit?
Another check ensure that there is no binding going on with the pads in the calipers...I had this issue with my kit I installed needed a bit of deburring and grease..

 

[ksurfer2]

It may improve with use.
Are the bleeders at the highest point?

Yes, the bleeders are at the highest point.

 

[ksurfer2]

Curious, did the master come with you kit?
Another check ensure that there is no binding going on with the pads in the calipers...I had this issue with my kit I installed needed a bit of deburring and grease..

The brakes and master cylinder were on the car when I bought it.

 

[BB BELLA]

when you say all bled out that leaves only a mechanical problem.

I would check pedal assembly for play under dash to be sure pedal pressure is being applied correctly to master!
new flex hoses installed?
check caliper sliders to make sure there free.
jack all 4 wheels up and have an assistant attempt rotating wheels with no brake applied and with light peddle pressure and compare the brake application at each wheel!
pressure test the master or try another one!

 

[Ron H]

If the MC might not have been bled sure think it should have been or done properly (it can also be done on the care with care) bleeding the brakes all day won't remove air from it. Can't tell; someone knowing more could say, but that MC doesn't look right for the 4w disks...looks smaller than it should be if you have multi-piston calipers. Don't want to open a can of worms...just tossing out possible checks.

 

[ksurfer2]

I will first try bleeding the master cylinder. I suspect that may be the issue.

 

[EARLY B]

Bore size of the master cylinder ?

 

[Darter6]

Mushy on the first application? Does it firm up on 2nd or third pump?
Is it equipped with a adjustable proportional valve to the rear wheels?

 

[ksurfer2]

Mushy on the first application? Does it firm up on 2nd or third pump?
Is it equipped with a adjustable proportional valve to the rear wheels?

It does not firm up much. There is no proportioning valve.

 

[Thunderlugs]

Bore size is important . 15/16 gives you more pedal pressure and stopping power with less leg pressure. Is your brake bias adjustable ? you might need to ad a manual adjustable valve, if your system doesn't already have somthing in place .
Check for any slight seepage at the hose to caliper connections. Those wahers can mess with you.
Also make sure no slop in pedal rod.
Leak in the back side of master, or an internal master cylinder bypass.

 

[MoparDanMan]

My 64 dodge has a VERY mushy brake pedal. I have manual brakes, wilwood disc brakes all around. No squeaks or squeals out of the brakes, car runs straight under braking, stopping power is marginal, at best. I have bled the brakes, fluid is fresh and clean, no air pockets. No leaks. Attached is a pic of the master cylinder. What should I check? View attachment 1018951

I've never done a disk conversion without also adding a power brake booster, but I have read that 4 wheel manual disk brakes are less effective and can feel spongy. Just a thought.

 

[Ron H]

I went through a shitstorm with my brake conversion for eons. Was reluctant to replace brand new parts (MC and booster in my case going from manual to power) but after effing around long enough said eff it getting a new MC and booster, not that much cash anyway. Some checks I should a done sooner than later as mentioned; but my guess considering a spongy pedal, pedal sink, and poor braking, all the stuff I did finally garnered success. Also had issues with pedal travel, gap, and ratio in this mix going to power brakes. System compatibility is big as has been posted to assure MC delivers ample pressure and fluid for the system...

 

[Darter6]

The master on your car in the photo is the aluminum/plastic Mopar used in the 80's.
Most of those cars were disc/drum.The residual pressure valve for the rear drums may have been removed for rear discs.
That may be the cause (maybe) for the spongy/mushy pedal.
In the photo the line lock valve looks higher than the base of the master.This may be the cause,trapped air in the line.
Another maybe,just shootin' in the dark here.

 

[ksurfer2]

I appreciate all the input. At least I have another reason to spend a day in the garage!