Okay, I don't usually mess with brakes but me and my buddy changed my rotors and pads out a couple weeks ago. Everything was good until last weekend, we too them back off for suspension mods. Now my brakes don't grab witht the whole pad. With the exception of the front drivers side, they grab just barely the outside edge of the rotors and the rest is turning rusty. Someone said its air int he brake lines but I'm not sure how that can be if the lines were never opened. Anyone have any suggestions?

 

If they only grab the outside edge, its probably a problem with the caliper or sliding pins or ... a wild guess ... possibly they are the wrong rotors and are too small.

Pics?

 

Sorry if my post was confusing I just got out of surgery a few hours before, still drugged up. The rotors are OEM replacements identical to the old ones.
Front passenger

front driver

back passenger

back driver

 

Those rear ones certainly look wrong and that front passenger one isn't quite right either.

I doubt thats a problem with the lines (although anything is possible). There may be something wrong with the caliper pistons or the sliding pins. Inspect the pistons for damage (they may be crooked in their bores) and inspect the sliding pins to make sure they aren't stuck. Also take a look at the caliper body and the pads too to make sure there isn't something else wrong with them. Are there any pad clips missing? How do the pads look?

I don't know what's wrong, but that's where I would start looking.

What is that gray stuff caked on the front passenger caliper bracket?

 

The gray stuff is some JB weld, don't ask. Could the bolts to the sliding pins be overtightened? I know my buddy put them in there really freaking tight. I'm having a hard time figuring this out because it was fine until we took it apart the second time. The pads and rotors all have under 500 miles on them, almost brand new.

 

OK, stop. Replace that bracket. JB weld is not good enough. You don't want that bracket to fail. Any other bad repairs like this in the system?

That shouldn't make a difference on the sliding pins ability to slide. It will however make removal more difficult.

 

The JB weld isn't actually a repair to the bracket, it was on the table and the bracket, well, welded itself to it. I took it to a brake shop today and they looked at it, had no idea what was causing it. So I'm pretty sure I'm in for an astronomical diagnostic fee if I have a shop get into it.

 

Some of that JB weld, or maybe some paint, seems to have made it to the pad clips.That's not good. The clip will deform slightly under braking load, and you want it to deform evenly.

Nothing you can do to the lines will cause that wear. It looks like spread calips, but they shouldn't have spread so suddenly, and rears rarely spread.

If the sliding pins are or were dry and worn, rotating them the flat spot during the last servicing could have caused a problem.

 

i guess you could simply seat the brakes a few times(60-5mph) hard braking but not abs and see if they will seat......or wear to match the angle of the rotors.....some1 could have turned them and they are thin in the middle and think towards the outsides...

could be the backing plates/brackets

 

Well, I'm thinking just spring for a new set of pads, regreasing all of the pins, getting rid of that JB weld (I didn't realize it was a problem, it was still tacky so I just flattened it) and getting the rotors turned, and seeing what happens.

 

I noticed the flat spots on the calipers guide pins when I was chaning my brakes a couple of weeks ago.

How should the flat spots be oriented. Should the face of the falt spot be towards the the pads or facing up, 90* away from the pads? If that makes sense...

 

Yeah I would be curious about this myself, I didn't even realize they had a flat spot.

 

I don't thing it really matters.

 

The orientation of the flat spots doesn't matter. They are only there so that you can use an open-end wrench to hold them still while you tighten the bolt that goes into them.

 

Oh ok, I thought you meant a flat spot on the pin itself.

 

The pins are flattend on two sides so they need to be oriented in the caliper bracket properly. If your pins arent sliding properly or smoothly, give them a light coating of anti-seize and stick em back in the holes. You will notice that they will go in better one way than another. Hopefully that will fix your problem.

BTW.. when you look at the end of the pin from straight on (from the end that goes in the bracket) it will look like..

._
(_) .... Sorry.. best I could do with text, but hopefully you get the idea.