My 97 F150 was sitting for awhile, and when i went to go and drive it again, there were no brake at all. The truck would sometimes NOT stop at all, and would "slam" on and off. The truck would shake, and there were no brakes. So i replaced the pads, and the rotors looked like they had been done before i got the truck. While going for a test drive, the truck stopped better, but not very well. While slamming on the brake, i blew up a drivers side brake line. I replaced that brake line, bled BOTH sides 2 times and still no brakes. I topped off the brake fluid and everything. Im guessing its the master cylinder or the proportioning valve? Help me out quick, truck is rolling down the hill with no brakes

 

thats not a pads/rotors problem. it sounds more like the proportioning valve is shot, or the master cylinder has something going on with it. either way, its a hydraulic problem.

 

Repalce your other brake line also, I understand that the lines get soft inside and don't allow enough pressure to operate the calipers, thus you will have a soft brake peddle or no peddle. You can't tell by looking or squeezing the lines if they are bad. Worn brake lines can also cause the calliper to freez up.

 

If it had been sitting for a while there could have been moisture in the lines. Our 1980 F100 did this on the front brakes. Disconnect the lines from the master and blow them clean with air and then refill and bleed. It will make a world of difference. It may still be a valve or something else causing your problem also, but this is what we found on ours. We also replaced the flexible lines just to be sure. They tend to deteriorate from the inside out.

 

You know what, don't mess around with your brakes. If your having problems replace everything or take it in and have it done. For something that has been sitting outside for a while, you problbly have condensation in the slave cylinders and the like. Don't try and save money on the brakes! Everything else, fine.

 

ANother thing is you can't go out and slam on the brakes. YOu have to allow a few hundred miles for the brakes to seat properly. If you don't, they'll squeal and perform poorly. Chances are, you've glazed the rotors and ruined the pads.

 

Also, if your truck has been sitting a while, you might have moisture in the brake lines. Have them flushed out/bled and new brake fluid put in.

Mike

 

Mike is right, and it seems when water gets into the lines it settles to the bottom which is the slave cylinders on your calipers. This has another bad effect as it will cause corrosion in the calipers that will make the pistons stick which will be noticeable in many different ways and cannot be cured unless you rebuild the calipers. I just had my brake system flushed for $39.95. It's safe insurance.

 

Might be time for new brakelines, bleeding them might work too. I never had such a problem but the way I drive I hope I dont