brakes dead again after 4k miles...

Oh well, here we are again. '00 XJ sport shakes like a leaf when braking. I had some vibes in May that varied with brake application, but also persisted when going 50mph. Wheel balance solved the 50mph problem (one wheel was definitely way out), but there were still vibes when braking. Using autozone parts (calipers were replaced under lifetime warranty) I put on new calipers, pads, rotors, flushed fluid, good bleeding. All was well for about 4k miles.

The last brake job lasted ~30k miles, this one ~4k? Any thoughts?

I can think of 2 discussion points. 1) The caliper bracket 'slides' on which the pads rest have some grooving, maybe the pad is hanging up, or 2) A bad hub is causing strange brake wear. I had a squeak a few winters back, only when just moving from a cold soak. Was sure I'd have to change a hub, but the squeak went away and hasn't come back.

I'm getting tired of doing brakes on this thing!

Duralast pads?

Mine wear out within a year....down to bare metal. My sliders have grooves in them so I'm sure that didn't help either.

My experience has been that autozone rotors suck. I have had 2 sets of rotors warp in a very short period of time after installing them. Ever since, I have bought my rotors from Napa.

What ya gotta remember in the aftermarket parts world is, you get what ya pay for. You buy cheap stuff, don't think they will last forever.
That being said, are you sure you torqued the studs in a star pattern as to not warp the rotors. If you did you would feel the pedal pulsate a bit or maybe the steering to shake a bit when applying the brakes.

4k miles is not right? Are you sure it's not a suspention issue? Have you pulled the pad's to see if there used up?

As said before, you get what you pay for. NAPA has very good parts. What type of pad material are you using? Ceramics, if not broken in properly, can crystalize and build up excessive heat as well as noise problems. The issue with grooves in the knuckles can cause problems as well (i.e. uneven wear, excessive heat, etc.). Take care of the knuckle problem first. Pads hanging up cause alot of heat and wear. Then you can determine if the parts are the culprit. Make sure the rears are adjusted properly so the fronts aren't doing all the work as well. Were the pads worn out, or did you just have the pulsation in 4k? How the steering damper?

2X the frozen caliber. 4K on a set is just TO short a time. You got more problem then cheap parts. I use cheap parts. They DON'T last as long but the high price stuff don't hold up that much better in my book.

(IMO) For DD most Ceramics suck.

Ive also read that replacing the pads and rotors at the same time won't allow both items to heat up and "brake" in properly (pun intended).

The drums could stand to be checked. The last recorded time I checked was at 86k, when the last set of 'cheap parts' brakes went on. I swear I checked them when doing a tire rotate somewhere between then and when I did the most recent brake job (just after 100k), but I didn't record it.

Pads most recently were duralast gold, semi-metallic (one level up from the basement!) I used peformance friction standard (not Z) at 86k. I think those were out of stock at 100k, but I liked how those held up for the money. I usually follow the get-what-u-pay-for rule, but I don't expect these things to last forever. I subscribe to bardon's point of view, when I do pop for the more expensive parts, the benefit often doesn't measure up to the extra cost. I like NAPA parts over autozone, but the counter guys at the napa near me are awful. Maybe it's worth dealing with them again...

Other stuff...I'm pretty careful about torque, use a trusty snap-on tq-wrench. (slient_bob, I get steering shake and pedal pulse now, was totally smooth just after the brake job) Also, I take the 'bedding' process seriously. Oh, and I did shocks and the steering stabilizer this summer. 98XJSport, I've never heard that about replacing both items together. The concept is interesting, but what do you use if you need new rotors? Certainly not old pads... I've done new pads on old rotors without turning with success (I did not do this on the recent 2 brake jobs).

Thoughts on fixing the sliders? They are cast, so I need to tear the thing apart where a good welder can do his magic. That, or dare I say JBWeld? I've never tried to machine JB, so I don't know if it will just fly off when grinding the slider smooth. I wish these darn things had the little stainless shims I've seen on other brakes that protect the slide surface...

Thanks for the input, gang. Maybe there will be some time to tear into this for inspection this weekend.

mark

Bought two new Napa Premium Rotors and I turned them just because. It took 3 cuts to clean them up, true story. They were warped right out of the box about .008".

Torquing the lug nuts to the proper spec is also important especially on the front. Unevenly torqued lug nuts cause rotor warpage, yeah, really.

Holy crap, 3 cuts out of the box? Gotta love sloppy manufacturing tolerances!

I've got an indicator, so I'll probably slap it on there to see how bad they are right now.

I also have the last set of rotors I took off, I could have those cut (it was easier to get new ones, less trips out to the auto parts store).

No suggestions on how to fix the slider surfaces?

new pads and rotors at the same time is fine( thats how your jeep came from the factory):doh: I would recomend WAGNER thermoquiet brake pads, I get them from Oreily's,not sure who else sell's them. they are they best pads out there for the money, the don't squeal, they don't dust your wheels,and have a lifetime warranty,and it's not the kinda warranty you need because they wear out every six months like other crap.

on the sliders if you have acsess to a welder that is the easiest option, if not depending on how bad they are might need to replace them.

Wagner Thermoquiet Pads. That is what I just put on. They are the ones that include stainless steel shims. I replaced the rotors with Wagner too. Works sweet.
Note: I also replaced the rear wheel cylinders and shoes at the same time. One piston on each wheel cylinder was stuck.
Yea, they work like new again....

Do the shims slide over the rails or what?

I'll bet they are back shims, where you'd put the anti-squeak goo.

I have to look into ATE pads and rotors, company discount...

the shims attach to the pads at the top and bottom, the are to take up the slack from worn guides.... wagner pads don't come with anti-squeak goo, they dont need it,most A-SG is crap anyway and wont help cheap from squealing,so I'd throw it in the trash.

Maybe I could grind the guides down a bit until they are a bit more smooth and take advantage of those shims!

I hate anti squeak goo, it can be a mess, and doesn't eliminate squeak, just reduces it.

I did jack up one front wheel yesterday and check for a bad hub by trying to rock the wheel at 12 and 6, found no play. Even put a pry bar (6 foot long!) under the tire and pried up to see if the spindle moved WRT the axle, nada. Unfortunately, only time for an oil change today, too much fall yard work...

Ok, jeep is in the air, wheels off. Front rotors were hard to turn initially by hand, but by the time I tightened down some nuts for a dial indicator measurement, they freed up to some degree. The rotors had at most 0.002" run out. To me, that ain't warped. The pads are in good shape, the rotors look clean, no gouges, 'high spots' or other defects.

Rear drums, only got one off so far, the other is rusted to the axle flange. PB blaster is at work. I don't have a tool to measure the drum diameter, but they look clean and even. The shoes have ~1/8" (less on the front shoe, more on the back shoe) left down to the rivets. Chilton says 1/16" min. No apparent leaks from the cylinders. I've NEVER changed rear brakes, 105k miles. I'm starting to wonder if the combi valve is not working the rears hard enough. the e-brake has always worked great.

One other weird item worthy of mentioning, one rear axle has ~0.015" of endplay. I didn't measure the other. Seemed like a lot of slop. Any idea what's allowed? I should go look thru the book again...

Mark

The 00 is a c-clip axle, so some in-out end play is normal. My YJ had about 1/8" end play when it was new.

steering componets shot (was brakes dead again after 4k miles...)

Well, got it all back together and had the wife crank the wheel back and forth while I held onto the steering components under the truck. Something is worn. I think its the first link between the steering arm and the right spindle. I also now notice a clunk in the steering when manuvering at slow speed in driveway. I think it's that joint popping. Time for some new parts... The rest of the system feels good, but I hate to replace just that one part and then get an alignment. Based on another thread, I also want to get a ZJ tie rod assembly. I'll have to collect all the part numbers and then post to check for correctness...