I bench bled and replaced the master cylinder. Due to ground conditions, I couldn't jack up the truck to bleed the brakes and used it with mushy brakes for one week. I took it to a mechanic and had him bleed the brakes. This was no help. I took it to another mechanic, told him what I had done, and had him bleed them. It still has the same problem. When I put pressure on the pedal, it stills goes down to the floor. Is it possible that air entered the master cylinder during the week I used it before I had the brakes bled or could it have something to do with the ABS modulator or something else? I know no one checked on the modulator and neither checked their work after finishing it to see if it worked. They just said it had been done and charged me for the work.
My car has 230000 miles.
My car has an automatic transmission.
You are going to have to get the brake system pressure bled using a pressure bleeder and a scanner capable of activating the ABS bleed function. Until this process is done, you will not get a good brake pedal. The bleeding process may need to be done several times to get all the air out of the ABS modulator and brake lines. If you need assistance with this, a certified professional from YourMechanic can come to your car’s location to diagnose the brakes and ensure that all the correct repairs are done.