1998 auto 2wd ranger
Replaced all break lines and master cylinder.
I have bled all the lines an properly bench bled the master. With no air coming through the bleeders anymore. I can pump them up and have pressure but after a few minutes the pressure is gone but will hold if I keep it depressed. I start the truck too see how the pedal is but it just goes right to the floor with it running. I have tryed everything to no avail. It has a rear only ABS system in it. For the life of me I can't get a pedal. Iv done 100's of cars breaks an never encounter this and can not find anything on my specific problem. I watch ur videos pretty offen an usly a great help with what I might be stuck on so I figured I'd ask you if you had any ideas or mabe I'm missing something.
Plz help lol need the darn thing back on the road!
Did you replace rubber brake hoses as well? They can weaken and expand under pressure.
It's possible you got a bad master cylinder. One of our people here, @justin-shepherd, as I recall had to go through 3 brand new OEM GM master cylinders before he got one that actually worked for his '79 Pontiac. Unfortunately it's been a race to the bottom for quality in both aftermarket and OEM parts in recent years.
@chucktobias is right, that was the most irritating brake job I've ever done, haha. I would double check that your brake master cylinder isn't leaking through the rear seal. You may see a wet streak down the booster. Two of my new masters leaked from the rear seal. The first one failed after I put it under booster pressure. The 2nd one seeped back there as soon as I bench bled it. It wasn't even on the car. The 3rd one held fine and has since, *fingers crossed*. They definitely aren't making OEM stuff like the old days.
I would check the rubber hoses as Chuck said. I replaced those in my old Pontiac as as well, but they were well over 20 years old. Also check your lines to the rear for seepage, in case the flares aren't seated correctly, and make sure your wheel cylinders aren't leaking inside the drum. Had both of those happen as well on the Catalina. My 1999 Ranger also blew out a rear line earlier this year, and the Pontiac had a pinhole leak in a rear axle line that wasn't obvious. Brakes have loved me this year.
