madmanmarty

I already did a search,no luck.
Took my '94 out for a 6 mile round trip this am. No problems.
My son takes it a hour later,gets a few miles and the front?(for sure) brakes start grabbing badly. Turns around and it starts overheating.
Makes it home with just a little coolant spilling,and temp idiot light comes on.
Both Front brakes were very hot.
Questions, 1- would resistance from brakes cause overheating,
2- should I look to master cylinder first for brakes sticking?
This has been on the road for only a few days since last fall due to other issues( blower motor,blower resister,starter,battery,oil filter adapter).
PO did a brake "job" prior to my purchase. He replaced front pucks.
Any suggestions on what steps to take for repair would be appreciated.

toasterknight

Brakes locking is typically the caliper degrading. If it was having to work especially hard to overcome the brakes and had a cooling issue it could cause an overheat.

4WD4EVER

I'm with toaster. I had a similar problem on a '97 project I recently sold. Rebuilt calipers, turned rotors, new pads and new fluid and it was good as new.

The problem was the calipers. The rest I did due to the intense heat generated and I just wasn't comfortable re-using.

Edit: I also inspected the rear cylinders for my own piece of mind.

toasterknight

I wasn't even comfortable turning the rotors when mine did it. I had to limp 12 miles back to civilization. The stress microfractures from the heat were scarry. I just replaced it all.

4WD4EVER

That's a great point toaster. Fortunately, I'll bet I didn't drive that thing more than a couple hundred miles after that and maybe a good thing I didn't!

madmanmarty

Update.
Got son to describe event.
Made it close to 3 miles but knew the jeep was working too hard and something was wrong. Turned around and everything started getting hotter.
Calipers are not seized,but jacked up and checked drag.
Definitely too much drag.
Thanks is for the advice.
What worries me is that both calipers were smoking and drag is bad on both.
The odds of both going at the same time is high.
Before I replace the calipers,is there a way to check the master ?
I did have my boy hit and release the brakes with it jacked up,and it did release but with too much drag.
Am I still back to calipers & pads?

toasterknight

When I got home we sat in the driveway for nearly an hour with a fire extinguisher. It was smoking really bad so I would assume mine was an extreme case though.

Rogue4x4

Check the knuckles.

The pads slide on the knuckle, and over time can create a groove in the metal. To remedy this you need to replace the knuckle, or put new weld material there, and grind it smooth, back to original. The knuckles are cast. So be aware of that. Preheat the knuckle, fill with weld, cut/grind to smooth, Bob's your uncle. No more sticking calipers.

Dumajones

^^^^^^ x1 ,,,What Roni said here is some reading about what he is talking about and what the fix would be if you do have bad grooves in the sliders/knuckles.

http://www.jeepforum.com/forum/f9/xj...rooves-924713/

Rogue4x4

Duma to the rescue. Wanted to post that but couldn't find it. Thanks for that, good looking out.

Dumajones

No prob..when my 95 had the right brake locking up/dragging getting hot..Did that fix in the link,,and boom all fix.. still kicking butt to this day. But now the left kinda needs it,, lol

madmanmarty

Thanks roni and Duma.
I'll check the knuckles tomorrow.

SteveMongr

1) Yes, should also smell the stink of burning pads.
2) No
3) Calipers are highly suspect and should be replaced (unless this is garage kept, but if parked in the grass or dirt for a year than there will likely be corrosion issues).
Address the tabs on steering knuckles as mentioned. Can usually be filed smooth, until the wear is excessive.

Turbo X_J

Check for water contaminated (milky) brake fluid.

dans98xj

I had a problem like this and it ended up being the rubber brake hose from the body to the caliper. When they get old the inside can fray and not leak but also not let fluid to return to the master cylinder.