Technical Brake goes to floor when started

I’ve got an issue with my 1955 Chrysler 300. The pedal is hard as a rock when the engine isn’t running, but nearly goes to the floor as soon as the engine starts. Bleeding it doesn’t seem to do anything.

Any ideas????

Thanks guys!

Josh

 

I think your power assist is applying enough force to overcome something marginal in your system. If it is not leaving a puddle somewhere, my first check would be the master cylinder.

 

Pedal Rod/Booster Adjustment Correct/Checked?

 

4 wheel drum? Make sure they are properly adjusted, that almost always brings up a low pedal.

 

Free up all the linkage between the pedal, booster, & master … it might even fix itself once everything can move as intended.

 

is the peddle moving on it's own when you start the motor? i may be reading it wrong but had to ask.

 

Thank you guys! I'm going to try all this tonight.

I have no doubt the shoes need better adjustment. I'm also going to bleed everything again. Lastly, I'll check all and any linkage and/or adjustments. I appreciate the help! Fingers crossed!

 

Don’t adjust your push rods tight ( pedal to booster/ booster to master)
You need 3/16 to 1/8 play
Adjust your shoes so they just start to drag
Check your pedal.

Does the car stop or not?
How are the brake with out the booster?
Can you drive the car?

 

Those brakes are difficult to adjust correctly without the special tool. Can be done, just takes a lot of time. That is especially true after shoes are changed or drums turned. More background info may help pinpoint the problem. The manual has a detailed 'no special tool' procedure. Follow it to the letter and they may come up. Normal 'bendix' brake procedure won't work.

 

Center plane brakes? Read up on them a bit.