Brakes wont hold

Hello Patricia,

Have you checked the master brake cylinder reservoir for brake fluid loss?

I don't suspect the master cylinder as you have replaced it... but am more suspect of a leaking brake line or fitting which should have
been discovered when you had the system bled.

The only time I ever had a rear brake problem with a 2500 series Chevrolet was due to seized rear brake caliper guide pins...as your calipers are also new that is not your problem.

If your brake pedal feels spongy and travels to the floor board you have air in the system, a brake fluid leak or a failure in the power steering system, such as a broken hose, broken power steering pump drive belt, or failed pump, would result in a loss of pressure to both the hydro-boost and steering.

Find more information here:

. Hydro Boost Power Assist Systems Operation Diagnosis and Repair

That would mean the caliper on the left is not working.

SOUND LIKE BRAKE BOOSTER BAD IF BRAKES WONT HOLD WHILE ENGINE RUNNING.BRAKE BOOSTER NOT HOLDING VACUUM,IT HAS A LEAKING DIAPHRAM. IF MASTERCYLINDER WAS BAD BRAKES WILL GO TO THE FLOOR WITH ENGINE ON OR OFF.AND YOU WOULD SEE WARNING BRAKE LIGHT FLASHING.

USUALLY THAT HOW THEY ARE

e-brake pedal should go farther- is either out of adjustment or cable frozen- secondly sounds like only front brakes receiving enough pressure to "activate" properly- bleed all four brakes starting rear pass,then rear drive ,then front pass, then front drive- use plenty of fluid- bleed till fluid is clean without bubbles- will that long at first- this will insure not bubbles and no moisture- if a pro valve dies,you would have more problems- pedal would be really soft,would have both a brake light and abs warning lights

check the vac yube on booster for vac. if none replace hose or connect. if good vac. then probably bad booster.

go online to autozone.com, sign up(its Free and safe) then go to their repair guide section.... it is priceless

your brake hoses have failed internally. replace your rubber brake hoses. this is a common issue on older vehicles

check the switch on the brake pedal

It is most likely a bad front wheel speed sensor.Your sure abs rings were on back of rotors?It is going to be next to impossible to fix without getting the code with a scanner