I have a 97 F150 4.6 2x4 with a break problem. My mom drove my truck for awhile and told me her breaks were grinding so i go over to her house. And one of the front pads was damaged so badly it wore into the caliper and trashed the router. So i decided it was time for all new breaks. I replaced both calipers, both front rotors, all new pads and new shoes, new drum kit for rear end new break rear cylinders. i also replaced the master cylinder and break booster. I bled the break system quite a few times with my brother and we researched it and did it the right way more than once. still my pedal goes to the floor when my truck is on. when its off it gets tight but right when you turn it on it goes to the floor. I have no clue how to fix this problem or where to begin. Any help would be nice. THANKS for taking the time!!!

 

It could be the booster or the master cylinder. It's gonna be hard to tell because you replaced everything.

How does the truck stop?

 

It doesnt stop. I cant even drive it. I have 0 stopping power. I replaced the booster and master cylinder already. Is there anything else it could be?

 

Did you bench bleed the master cylinder before you installed it?

 

Rule number 1: Just because it is new does not automatically mean it's good!

Since you basically broke it when you did all the work, you either have a faulty part that was installed or a faulty procedure was used.

Does this truck have rear-only ABS, 4-wheel ABS, or no ABS?

 

I bet he just has RABS on a 97.


1. Brake booster-to-brake master cylinder push rod adjustment.

2. The bench bleed was not performed, or done incorrectly.

3. Still air in there.


Carry out the brake master cylinder component test. Not from Haynes/Chilton; - From Ford Service.

 

Be VERY careful when adjusting the push rod. I find that if you turn it just a bit too far what will happen is "initially" as you drive off all is well but drive a mile or so and because it is adjusted just a bit too far the calipers were slightly compressed. then they start to heat and the rotors swell and then a few miles down the road they are totally dragging. Happened to me twice

 

Yea, that happen to me with a F350 once. Sort of, - New pads smoking , rotors warping. Sucked! But the push-rod adjustment was fine on this one. It ended up being the wrong pads. Weird ehh.

 

Come to think of it, I have never needed to adjust the push-rod. Not yet anyway.

I probably have the instructions somewhere for installing the booster, If he had a new one to install it probably came with some. But yea, I can't recall ever having to adjust the push rod.

 

I would use a bleeding tool, One of those deals that sucks the fluid out. Harbor frieght sells them for about $30. Gotta have a compressor for that one though. They reall come in handy especially if getting help is a hassle. You can bleed brake alone. When I did the Mach I's brakes that tool was a life saver..

 

Ok i did not bench bleed the master cyclinder.... Dont get mad at me i am a noob!!! hhaha. I will try that and get back to you on it.

 

One other thing i replaced the calipers, rotors, pads, shoes and new rear cylinders all at the same time and had this problem. did some research they said maybe it was the master cylinder so i went for it. Then i found this website which is AWESOME. So thats how it went down so it might not be the master cylinder. But I dont know.

 

the brake bleeder has to be on the top. Some calipers will mount on the oposite side upside down. My trucks rear brakes will do that. if the bleeder is on the bottom you never get the air out. I've installed lots of master cylinders without "bench bleeding" them..

 

ok I havent gotten to the master cylinder yet. But I did look at my calipers and the bleeder is on the bottom!!!! jethat you are a Ford F-150 Magician!!!!!! I am going to do that tomorrow for my project and i will let you know how it went. Since you pointed it out i am pretty darn sure thats my problem!!!! Thanks for the time for reading and the information on this thread!!!! I will post the results tomorrow.

 

Ok a bit of CLOSURE!! jethat nailed my problem on the money. My calipers were on opposite sides bleeder was on the bottom so i could not get all the air out. Switched sides bled them and i have BREAKING POWER!!!! Thanks again for all the help and time you guys take to read all these threads!