Join Date: Dec 2007
ds8508 is offline
Brake pedal fades, slowly after 4 wheel brake job
04 Blazer Extreme
I did a 4 wheel brake job this weekend. New pads and had the rotors turned.
I never opened any of the bleeder valves.
After everything was bolted back together, the reservoir had overflowed from the caliper pistons being pushed back in, so I used a syringe to siphon as much of the old fluid out of the reservoir as I could get. The reservoir is split in 2 and there is a baffle between the 2 parts so I couldn't get all of the old fluid out of the front portion.
Refilled with Valvoline synthetic.
I started the truck and pumped the pedal a couple of times and it got more firm, but never gets totally hard.
I had a friend who is a Ford mechanic come over. We bled/flushed all the brake lines; rear passenger first, rear driver, front passenger then front driver. We bled them until new, clear fluid was coming out. Bled by hand/foot, no mighty vac or power bleeder.
On the front driver caliper, where the brake line attaches to the caliper there was a VERY slight leak. I tightened the bolt and the leak stopped but this didn't change the pedal pressure (we did re-bleed this line). I suspect I might have hit this bolt when I was trying to get the rotor off (they were ALL pretty much rusted in place)
During the test drive there was plenty of stopping power, though we never tried for a total lock-up or to get the ABS to engage.
But, if you sit at a dead stop and push fairly hard on the pedal, it *will* fade all the way to the floor, though what I would consider "normal" pressure on the pedal doesn't seem to be enough to make it fade.
My friend didn't have any suggestions other than to try to bleed the master cylinder, on the car.
Any help would be greatly appreciated!
I'm 99% certain the pedal used to get hard about half way down and the brakes have always been REALLY good in this vehicle. It's the first thing anyone that ever drives it, always noticed; how touchy the brakes were.