Sticking calipers?

[the_dealer]

Hey guys, I've been trying to track down some issues with my 2003 kj limited (3.7, 45rfe). Its am early 03 if that matters. I just bought the thing with 186k miles on it for cheap, so I new there would be some problems.



The first thing, it feels like something is dragging when I accelerate from a stop. It feels like it takes too much throttle to get moving, but is fine once I get going. Gas mileage is around 17-18 if I grandpa drive it. There's also a low pitch metallic noise coming from the passenger rear wheel area. Happens during take off, coasting, and braking. My wife says she cant hear it, but it's definitely not right. The noise is hard to explain, but sounds like a roar/growl sound. Like metal grinding metal. Its speed related, and seems worse first thing in the morning. The emergency brake has to be pulled almost all the way up to engage. I tried to reverse and pull the ebrake, and i get almost the same sound. My front brakes don't make any noise, but it pulls to the right slightly when driving, then pulls to the right pretty good under hard braking(also the slight) vibrating feel warped rotors have) I made sure my tires were aired up correctly as well. I noticed today that the rear rotors were barely warm after driving, but the fronts were hot enough you couldn't touch. Both front rotors seemed heated evenly. I did have a burning rubber smell for the first week, but i never could figure out where it was coming from. Just from looking, all 4 rotors are glazed and grooved pretty decently. The outer pads look like they have alot of material left. The rear passenger(where im getting noise) caliper looks new, and it definitely has new rubber lines in the rear.



I haven't had much time to mess with it, but I jacked it up and spun the tires to check for resistance. The front tires are pretty hard to spin, and it takes alot of effort to go 1/2-3/4 turn. Im not sure if it's because of the cv's or what. The noise im getting from the passenger rear is present while spinning all 4 tires. The rear tires take half the effort to spin, and they seem to be freely spinning. Both rear rotors make the metallic grinding noise, but the passenger rear sounds like a warped rotor more so then the other ones. I also noticed what sounds like a box of marbles rattling in the rear passenger tire area. It sounds like its around the backing plate. When I was doing this, the t-case was in 2hi, and trans in neutral (2hi,4pt,4ft, lo). When spinning either rear tire, the driveshaft would turn a little and then stop.



Im looking for some advice on where to start. Obviously I need all new pads and rotors(quality ones), but should I do anything else considering my problems and mileage? Should the front tires be so hard to turn, and get hot? I drove 11 miles with very little braking when i noticed how hot they were. I should also mention i was getting a random pop from the right rear when taking off from a stop, but it hasn't done it in a while. It feels like im towing a trailer from0-15 omg. Any input will be appreciated. Tha ks!

 

[CactusJacked]

Sounds like the back brakes might not be doing their job. That would mean the fronts are doing all or most of the work, and you bet that would make them awfully toasty. The fronts shouldn't be that difficult to spin though. Replace the brakes, then go from there. And while the brakes are off, that will give you the opportunity to see just how freely the axles turn on their own.

 

[bassmanbob]

Got these when I did my brakes last spring break and they have worked significantly better than the metallic pads I pulled out, they leave absolutely no dust behind unlike the absolute mess with the other pads.
REAR:
ACDelco 14D981C Advantage Rear Ceramic Disc Brake Pad Set : Amazon.com : Automotive
FRONT:
Amazon.com: ACDelco 14D856ACH Advantage Front Ceramic Disc Brake Pad Set: Automotive

Another thing that would be good to do is change your diff fluid, that something that often gets overlooked especially on high mileage vehicles and could be contributing to some of your problems. Changing it out is insanely easy with a hand pump and an old jar.

 

[tommudd]

Got these when I did my brakes last spring break and they have worked significantly better than the metallic pads I pulled out, they leave absolutely no dust behind unlike the absolute mess with the other pads.
REAR:
ACDelco 14D981C Advantage Rear Ceramic Disc Brake Pad Set : Amazon.com : Automotive
FRONT:
Amazon.com: ACDelco 14D856ACH Advantage Front Ceramic Disc Brake Pad Set: Automotive

Another thing that would be good to do is change your diff fluid, that something that often gets overlooked especially on high mileage vehicles and could be contributing to some of your problems. Changing it out is insanely easy with a hand pump and an old jar.

I would suggest you do it the right way and drain and fill, you want to get as much of the old crap out which you never do if you're sucking it out

 

[the_dealer]

Thanks guys. I could see the fronts working harder and being hot, but the rear were barely warm. In the front, the wheels weren't hot, just the rotors. definitely plan to swap all of the fluids anyways. I might pull the calipers off and clean/grease the slides, and flush the brake fluid. I dont want to get new rotors and pads until I figure it out. I will mention, both front rotors have more glazing and grooves then the rear. When spinning the tires, both fronts were the same. Would the t-case not being in neutral make it harder to spin? And what about the rear driveshaft not spinning? I had both tires off the ground and it spun 1/4 turn then stopped, but the tires were still moving. On level ground, 75% of the time it won't roll without throttle. The other 25% it barely moves. My tj would start going when u released the brake in gear. From looking at the pads, it looks lile they were recently replaced, but the piston didn't go in far enough. Surprisingly the pads look new.


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[tommudd]

Thanks guys. I could see the fronts working harder and being hot, but the rear were barely warm. In the front, the wheels weren't hot, just the rotors. definitely plan to swap all of the fluids anyways. I might pull the calipers off and clean/grease the slides, and flush the brake fluid.
Good idea plus you could see how easy or hard the pistons go back in while you are into them

I dont want to get new rotors and pads until I figure it out. I will mention, both front rotors have more glazing and grooves then the rear. When spinning the tires, both fronts were the same. Would the t-case not being in neutral make it harder to spin?
Highly unlikely since you would feel binding when turning etc as well

And what about the rear driveshaft not spinning? I had both tires off the ground and it spun 1/4 turn then stopped, but the tires were still moving.
Normal
On level ground, 75% of the time it won't roll without throttle. The other 25% it barely moves.
Again normal
My tj would start going when u released the brake in gear. From looking at the pads, it looks lile they were recently replaced, but the piston didn't go in far enough.
If the piston didn't go far enough back in when new pads were replaced they would of never got the caliper down over the rotor
Surprisingly the pads look new.


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Time to tear into it :icon_idea:

 

[CzarKJ]

Sounds like you might need to check the parking brake tension and pads as well. Could be a source of some of the rear noise. While you are in there... haha

 

[TwoBobsKJ]

Sounds like you might need to check the parking brake tension and pads as well. Could be a source of some of the rear noise. While you are in there... haha

I agree with Czar. The "rolling marbles" sound is likely coming from pieces/parts of the rear parking brake pads separating from the plates.

Bob

 

[the_dealer]

OK so here's an update, the noise is coming from the front, but I guess the interior reflects and makes it sound like the rear. I took a mobile audio RFA multi-tool, and discovered where the noise was coming from. The front passenger was the loudest, with the front drivers side just a little lower. I didn't really have time to do much today, but it was killing me to find out. I picked up a couple bottles of brake fluid, some caliper grease, and some brake cleaner. I was able to pull the wheels today before the rain came in. I plan on jumping on it tommorrow to start taking it apart. I know I at least need new pads and rotors, and I plan on getting them after I fix the problem. I decided to spray some pub blaster to let it soak overnight. I want it to be easy as possible tomorrow. I've heard the pins can be aggravating. I noticed the clips where the pads ride are bone dry, and surface rusted. All of the pads have been replaced within what looks like the past 10k miles. Looking like they replaced the pads and the caliper piston wouldn't fully retract. At least that's what I'm hoping anyways. With that said, it started raining, and parts were already f'd up, so I sprayed the caliper down with pb as well. Especially in the clip/groove the pad rides in. I did all 4 corners, put the wheels back on and started pumping the brakes. I did a bunch of 5mph hard taps of the brakes, and I could hear them actually starting to release. Long story short, the pads retracted a little, and there was very little drag and no noise. The noise came back after the pb blaster burned off, but still better. Not a good idea to lube a complete rotor/caliper like that, but I figured i would need to spray the bolts anyways. It worries me that I could have some sort of front end problem, that the brakes are just a small part of. I don't get any CV clicking, there's no play, and the only other noise(besides the brake noise) is my sway bar links. Is there anything I should check while the rotor and caliper is off? I also noticed that I have a tow bar base plate, and breakaway switch. It was towed behind an Rv at some point, and had a supplement brake system. Could that explain both front calipers going out at once?