Bad Master Cylinder?

[Blown 346]

Heres a rundown of the issue.

 

 

2 years ago I replaced the original pads and rotors on my 04 SSS. I just went over all the brakes front to rea.r pads to rotors and only had to replace the rear pads. The brake pedal has been alot firmer in the past, after I replaced the rear pads, the pedal hasnt gotten better. The pedal will firm up when the truck is off and gets solid and wont move. Once I start the truck and pump the pedal, it doesnt get any firmer. I can actually push the brake pedal to the floor with some added pressure. Once the brake pedal travels about halfway down, it starts to squeek and doesnt stop until you either stop while moving, or when the truck is just idling when the pedal reaches the floor. I have no fluid loss, the truck does have brakes but only feels like 50 percent of what they should be. basically if I had to stop fast, it wouldnt happen. All the calipers are fine, no leaks, or split boots, none of the lines are softened. I was going to try and bleed the entire system and see if that helps. but I dont want to waste fluid if the master is bad. Im thinking it might be on its way out due to the low pedal.

 

 

Any feedback or similar experiences woud be great.

[SSplaytoy]

My pedal action sucks, but the truck does stop (eventually). It's worth the few bucks spent on fluid for you to try bleeding the system. It's better than wrecking and injuring yourself or others. How many miles on the truck? Have you checked for any vacuum leaks?

[simz28]

I would try bleeding it before you replace the master just to be sure. After the truck stops, does the pedal keep sinking?