Help with brakes somebody please... this is what the brake booster is doing..i changed old one...and this is a new second hand....somebody please
With engine off and brake servo vacuum gone by pressing brake pedal several times, you should have a hard brake pedal.
If not it a hydraulic issue.
Fill the brake fluid reservoir then slacken the pipes from the master cylinder. DO NOT TOUCH BRAKE PEDAL!!! Just let the fluid run out until no visible air bubbles, making sure you do not run out of brake fluid, then tighten brake unions on master cylinder and press brake pedal twice slowly, see if that improves the pedal travel.
If pedal travel better but not 100% then if you have proper brake pipe clamps, isolate individual brake cylinders at the wheels and locate where most travel is and bleed the brakes there .
If travel is worst at rear brakes but no air coming out when bleeding them, see if pedal improves when hand brake on, if so check self adjusting mechanism on brake shoes (cheap shoes have weal adjuster springs and let the pedal go bad.
If front brakes bled and no air coming out, check condition of front brake discs, if they have a big wear ridge there is a good chance the new brake pads are sitting on that and giving a poor brake pedal.
Ideally fit new discs, but if not grind off wear ridge on edge of discs, then drive around until brake pads wear in to match the worn brakle discs.
Note ant excess brake travel will feel much worse when engine running as sevo will increase the power pressing on the brakes from the pedal.
If still no good then try a good quality new brake master cylinder and bleed as I described above.
Do not reuse old brake fluid as it is contaminated and also will have small air bubbles in it which will make it even harder to get a good pedal.
