Rear brakes locking up

I took my Jeep to a guy yesterday, primarily to get a quote on fixing the power steering, but they do brakes as well.

It turns out this guy really seems to know what he's doing (If a mechanic can be a geek, he's one! He looks like he should be in IT).

He says my rear brake lockup problem is most likely caused by the front brakes not doing very much work.

There are grooves (worn) in the bar that the pads rest on, which prevent the pads from reaching the disk, hence the back brakes do the work.

He says he can weld up the grooves and grind them flat. He is also going to turn a new set of pistons (They're made of bakealite).Does what he is saying make sense or is he talking nonsense?

Groove problem does happen. Pistons? Calipers? They are so cheap most people just buy a rebuilt caliper. $15.00 to $20.00 I cant remember the last time I rebuilt one. 2000 xj- rotors, pads, drums, shoes, wheel cylinders about $200

needsrepair said:

Groove problem does happen. Pistons? Calipers? They are so cheap most people just buy a rebuilt caliper. $15.00 to $20.00 I cant remember the last time I rebuilt one. 2000 xj- rotors, pads, drums, shoes, wheel cylinders about $200

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That's about right, I got $170 or so when I priced out redoing my entire rear brakes on '97. Promptly decided to go with the ZJ brake swap and spent around $300 on the whole thing (parts, new pads, fluid, rtv to seal the diffs,etc). That was nice, it was like "do you want a brand new version of your crappy ass drum brakes for $200, or for $100 more would you like disc brakes?"


Yeah, I can't picture welding and grinding calipers to bring them back.

One hour of skilled welding costs about as much as a pair of reman calipers.

From my perspective, buying a remanufactured set of calipers, putting them on and bleeding them is much more cost effective than trying to rebuild your old calipers with the help of a shop. You *might* have rebuilt them all by yourself for cheaper than parts store remans, but not if you've got to have someone else do welding & grinding, etc... And to me, the parts store thing has one massive advantage: Ease of fixing the problem should any problem arise.

Rebuild the calipers yourself or with the help of a shop, and if/when something fails you basically have to get the shop to admit that they made an error in their labor to get any form of replacement. At a parts store, if a bleeder screw snaps off when you go to bleed the new calipers or a week in all the seals are shot, you go to the store with a receipt and your busted-ass calipers and get a new set. To me, that eliminates all advantages that come from doing it yourself or with the help of a shop.

I agree that turning a new set of pistons doesn't make much sense. For one thing, since they are made of bakelite, they do not rust and seize, so unless they're leaking or broken they are almost certainly all right. Those calipers last just about forever.

The worn caliper slides can be a problem, and I do think that poor front braking can contribute some to rear lockup, but in my experience the rear lockup is usually caused mostly by adjuster failure in the rear drums.

Before you make too many conclusions about which brakes are working and not working, take your Jeep out to some back road, or even a parking lot, and slam on the brakes. Read the skid marks.

One of the problems driving an American car in deepest darkest Africa, is that the parts are not readily available.

I can't even by an air-filter over the counter at a spares shop.
Reconditioned parts are not an off the shelf option. Daimler-Chrysler are an absolute rip-off.

A recent example was I took my XJ to a tuning shop to have a new performance exhaust system fitted. They told me the fuel pump was shot, which was part of my performance problem. They quoted me ZAR2500 (Roughly $350) fitted. DC wanted ZAR4500 (Roughly $650) just for the part.

Rear Drums have lots of little springs, clips, cables and links inside them. Any of them failing can create problems that would cause your drums to lock-up. Like mentioned, the most common problem is the self-adjuster seize up. As well, if you wear the rear shoes all the way down, and the metal back of the shoe actually contacts the drum, it will lock up. Since the stress on the rear drums are so much less than the front, its rare the rear shoes wear so much that you get to this point.

What your mechanic may be getting at is; Since your front brakes have so many problems, they didn't supply any breaking force and the rear drums did all the work and wore out. That is why he is hitting you up for repairs for both front and rear brakes.