No brake pedal when engine runs

This is about all I have to offer, other than a defective master cylinder

Going give you a link/ there is a link inside of it (lemme know if you do not understand the 'on vehicle' bench bleeding-That's in the link inside of this one)

https://www.2carpros.com/questions/1998-ford-f-150-cant-get-brakes-bleed

Return here with good news!

The Medic

Hello,

Check the bleed and adjustment of the shoes at the rear. Also if the master and booster have been off or replaced check the adjustment of the push rod into the master cylinder.

Here is a guide that might help you.

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system


Please let us know what happens.

Cheers, Ken

Thank you gentlemen for great advice, the only thing I have not checked it the power booster
rod adjustment.

Also my problem gets extreme no brakes when I start the car and the vacuum line is hooked to booster. Rod? Booster? Mc?
This actually happened before I replaced everything but rear wheel cylinders

The wheel cylinder could be causing all of your problems becasue they can let air into the system. I would start by replacing them.

Please let us know what happens.

Cheers, Ken

Hello ken, I did replace the wheel cylinders now, one did look bad, got excited because I hoped that was it, I put new shoes etc as well, but...still soft pedal and when car is started the pedal Gascony nothing at all. Goes straight to the floor, there was a parking brake link rod missing on one side??.
Anyway am I back to Mc? And maybe rod adjustment?
Thank you

Hello,

Please remove the master cylinder to check the push rod. It sounds like you are not getting all of the air from the system.

Follow this guide and try it again.

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system


Please let us know what happens.

Cheers, Ken

What measurement, or adjust rod out or in? Thanks