Sometimes there are brakes and other times there are not ?

So in moab in march I noticed that a couple times towards the end of the trip I would randomly loose all braking. Im not talking soft pedal , I mean like you just did a brake job and you have to pump them a couple times to get the pads to contact the rotor. I have a dana 60 front stock chevy calipers and a 14 bolt rear with 1/2 ton chevy calipers.

Initially I thought it was a hill climb issue but that proved to not be it as it now does it on flat ground randomly also.

So I swapped out the MC rebled the entire system and the problem is exactly the same. I had some one press the brakes while parked and inspected each caliper to see if anything stood out. With one front caliper I noticed when pressing the pedal it pulled the rotor in a little. This made me think a hub maybe loose so I jacked it up and tried to tighten it up but it was already tight. Which made me think maybe the rotor was being pulled in by a stuck caliper and then would let loose when I bump the bottom of the tire?

So I am wondering if it would be possible that the caliper is sticking to the bracket and when it lets loose I have to pump to get the pads back in contact?

I also noticed on the rear caliper that it had a little flex with pressure applied and figured this was normal. But hoped to have enough details to get some help.

Do you have some residual pressure valves in your system ?

I dont have anything like that. Straight from the MC to the wheels combo braided flex and hard steel lines.

Ford mustang hydro boost with abs removed is my mc setup

Clamp off the front and go drive it. If it doesnt do it its something in the front.

I didnt think of that. Throwing a vice grip on the flex line wont hurt it? I could do it on the flex line before the split

SBJeepn said:

I didnt think of that. Throwing a vice grip on the flex line wont hurt it? I could do it on the flex line before the split

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That or put a bolt in the master cylinder where the line goes in. I have seen sticking slide pins do what your describing. Something is pushing the piatons back in a little

Maybe ill pull the side pin and clean it and the caliper up and maybe put a touch of marine grease on it and then take some needle vice grips with me and go for a ride and that will allow me to isolate a bit

Had this happen on a hot rod and it was the wheel bearing were lose. If you drove for a while without hitting the brakes the rotor moving around had pushed the pads away and it would take a couple pumps to get them back in contact with the rotor.

So along those lines if even one rotor isn't running true that may be part of your issue.

Blase said:

Had this happen on a hot rod and it was the wheel bearing were lose. If you drove for a while without hitting the brakes the rotor moving around had pushed the pads away and it would take a couple pumps to get them back in contact with the rotor.

So along those lines if even one rotor isn't running true that may be part of your issue.

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This^^^. May not be wheel bearing per say, but something most likely is causing a rotor to run untrue and push a caliper piston back in. Mine does this also, but its because I am a cheap ass and put stock front type non floating rotors on the back of my yota axle buggy. All non full floater axles wobble a bit, so after a while I have a low pedal the first time I apply them. Not the case with a 14 bolt rear, but I still bet you have a rotor wobble issue at least at one wheel.

Finally figured it out. I pulled off the calliper I suspected had the stuck h block and it was indeed stuck. But with it off I could see a small contact spot between the caliper and the inner c. So I turned the steering full turn and sure enough when turning hard driver the caliper would hit the inner c and it would slide the Piston back in and then there would be no pedal till it compressed back down. Like when doing new pads and getting in. The first time. I took a flap disc and clearances just a little and the problem is gone. Lol what a process.