I WAS DRIVING AND MY FRONT RIGHT CALIPER BUSTED THE SEALS AND BRAKE FLUID LEAKED OUT OF IT AND MY WHOLE FRONT BRAKE SYSTEM FAILED AND I HAD NO BRAKE PEDAL PRESSURE AT ALL AND I WAS JUST DRIVING WITH MY BACK BRAKES ONLY. I REPLACED BOTH CALIPERS, PADS, ROTORS AND BLED THE FRONTS ONLY. NOW WHEN THE ENGINE IS NOT RUNNING WHEN I PUMP THE BRAKE PEDAL THERE IS SOME PRESSURE BUT IT SLOWLY SINKS TO THE FLOOR AND COMES BACK UP SLOW. WHEN THE TRUCK IS RUNNING THERE IS ABSOLUTELY NO PRESSURE IN THE PEDAL AND IT GOES STRAIGHT TO THE FLOOR. BUT THE BACK BRAKES ARE STILL WORKING SO COULD IT BE A BAD MASTER CYLINDER OR COULD THERE STILL BE AIR IN THE LINES OR SOMETHING ELSE? NOW THE WHOLE TIME THE ABS AND BRAKE LIGHTS STAY LIT ON THE DASH AS SOON AS I TOUCH THE PEDAL WHEN THE MOTOR IS RUNNING
Might be wearth you checking your survo the way to do that is take the top off you break fluid bottle get some body to pump your break and if you can see air bubbles coming up in your break fluid you know that the seals have gone in your survo hope info is helpful
July, 30, 2013 AT 8:02 PM
There's two things to consider. First of all, the master cylinder can be damaged when you run the pedal to the floor. This often happens when the system is being bled with a helper. To avoid that, never push the pedal more than half way down unless the master cylinder is less than about a year old. Crud and corrosion build up in the bottoms of the bores where the pistons don't normally travel. When you do push them that far the lip seals can get torn on that crud.
Second, on a lot of ABS systems you need a scanner to activate a couple of the valves to allow trapped air to bleed out. That is not a concern if the brake fluid reservoir never ran empty or if you have the rear-wheel ABS system. The scanner is needed for all-wheel ABS systems.