New repro Bendix master cylinder and brake booster problem

I decided to finally buy into the Bendix MC and booster offered by Pirate Jack. This is for a 67 Dodge Coronet with power disc/drum brakes

Found the MC has a boot retainer bracket held on by 2 bolts that prevents a flush mount to the booster, and not the tear drop shape that's fastened with phillips screw that would not have interfered. I removed the retainer, and the MC piston pushed out of the MC approx 1/4". I bled the MC, and installed on booster with all new hardware (same ratio as original), and bled the lines. Pedal was nice and firm w/ engine off, but w/ engine running, pedal is soft with lots of travel.

I suspect I need to adjust the booster rod length at this point, but found the MC with the retainer not fitting the booster odd. Pirate Jack confirmed the misfit also but had not explanation.

Anyone else run into this?

Boot is used on manual brake M/C not power.

If Pirate Jack didn't know that Pirate Jack is not where it's at.

He sent you the wrong M/C.

Yup.

The boot for the manual brakes keeps the dirt out of the bore. With the power brake booster the seal between the booster and master cylinder keeps the dirt out, boot not needed, and none will even fit.

1. Measure the depth of the recess in the back of the MC piston with the butt end of a dial caliper.

2. Cut a strip of light cardboard the same width.

3. Use this cardboard strip as a gauge to adjust the length of the booster push-rod.

In other words, the distance from the face of the booster to the tip of the push-rod must equal the depth of the recess in the MC piston.

The MC piston is being pushed out of the bore by approx 1/4" when the retainer is removed. Should the piston be flush to make this measurement?

When measuring the recess in the back of the piston, the location of the piston is irrelevant.

Simply measure the depth of the recess and follow the instructions, above.