awg

smelt burning this morn, the front LH disc was hot (and stinky)

not locked on, I got it home, keeping off the brake, it was ok just warm

on the rearward face of the steering knuckle, where the fingers of the inside pad run, is grooved out, (about 5mm x 2mm)..I am hoping people will advise mig welding & grinding that smooth will fix the issue

I lubed the slider pin when I swapped front suspension, and also have longer brake hose still to fit

sticky caliper can be an issue?

if the groove weld & new hose dont fix it, will swap a caliper off my spare

is it correct XJ calipers dont have o-ring/rebuild kits available, but a new caliper is used ?

fb97xj1

Weld the knuckle and grind it smooth. Road test.

Ralph77

There might be new calipers available but I never noticed any in my travels. Ones at Napa are remans.
I used '96 cause that is what I saw in your profile. According to the Napa site these are available:

https://www.napaonline.com/en/p/UBP8...earchIndex=App

https://www.napaonline.com/en/p/UBP1...earchIndex=App

https://www.napaonline.com/en/p/UBP8...earchIndex=App

https://www.napaonline.com/en/p/UBP6...earchIndex=App

https://www.napaonline.com/en/p/UBP8...earchIndex=App

Now is this everything you need to rebuild a caliper? Not a clue.

awg

good thing I got my MIG consumables sorted the other day

Thanks, looks to be, I couldnt find it online out here in Oz

I only just noticed caliper OH is covered in the FSM

with much older vehicles, the piston gets rusty, and the seal compromised, so a rebuild near 30yrs would not be extravagant

I will just weld both sides up 1st though, systematic diagnosis, one thing at a time..i noticed they needed doing at the suspension swap, and I'm pretty sure that LH inner pad is wedging in there somehow

Ralph77

Have to see if I can find it in my '00 FSM. Awhile back I started thinking about how calipers rust. It bugs me a little. So instead of trying to refresh them whole I was wondering about maybe taking them apart, refreshing the housing with something to ward off rust, and rebuilding them.
Did a little research on rebuilding calipers and about the parts to do so. Only reason I am aware they exist at Napa. That is about as far as I got. LOL.

Dave51

Is it the top or bottom slider? I know everybody is always saying get the welder out, but I'm not seeing how that would cause problems, as it would seem to get a little sloppier rather than stickier. Plus I'm really not seeing how people can create a nice machined surface running an angle grinder, probably upside down, by eyeball, if there's extensive wear. Need to do a search on that.

I've found several cases when there are small notches. That seems pretty easy to fix:

https://www.jeepforum.com/forum/f9/x...rooves-924713/

https://www.cherokeeforum.com/f2/wal...repair-182084/

Gets my vote.

awg

welded up those 2 grooves, and smoothed them out finishing with flap disc on grinder

we will get to find out if this is the issue, as I had to rush, and only had time to just do one side

imo, there is a definitely an issue with the metal pad finger transitioning that groove, it could hang up, and wedge the pad or caliper

i do know of someone that burned up new pads, after not fixing this

did a quick test drive, and the welded up side disc was somewhat cooler than the other side, so that is a positive indication

dave1123

You can use a c-clamp to push the piston back. It should go easy and smoothly. If you have to torque on the clamp, you've got a sticky piston. The only thing that retracts the piston is the relaxing of the square-cut seal ring and if it sticks at all, the ring won't do anything.

Dave51

Let's see your weld job!

awg

gonna have to wait till I do the other side, I was rushing & swearing at the end, but did try and make sure the mig was ground flush & smooth, without removing excess off the knuckle

smooth enough you couldnt feel it with a fingertip

I would have preferred to have gone further & polished with finer grit, and will do that on the other side

must take a lot of force to grind those trenches...almost looks like they should be there, except 2 of my 96 have that wear, one doesnt

hopefully the hardness of the mig will be enough

have an IR gun, might use that to check each side

awg

UPDATE;

havent driven a great deal, but having been monitoring the temp of each front disc with an IR gun

the vehicle seems fine, no smell, however, the temp of the disc on the "trouble" side is running ~10-20% hotter than the other side

example, after 1hr driving in traffic, jump out and read disc...at extreme outer is hottest

LH disc max 375F..RH disc 300F

corresponding % on less arduous use...ie 20min drive

this is a little confusing, as the serious issue of pads cooking seems to be resolved by welding, but I cannot explain the higher temps

the disc on both sides are a bit "ridged" on both sides

I will probably next replace the hose, check the discs for acceptable,,,after that swap cailper off my spare

a complete new caliper is $145, a complete rebuild kit $75...available & priced in Oz pesos

Dave51

So you got photos of your weld job?

Did you preheat the knuckle before you welded?

Cummins93

Assuming the grooves have been taken care of, when you greased your sliders did you take down the rust and scale inside the slide bores? Rust will close the tolerance and prevent the slides from moving freely even with fresh grease. I've had the exact situation happen. New slide seals can be purchased at the auto parts store.