N8N

Hi all,

just got call from garage, apparently I need new pads and rotors to pass inspection despite the fact that the vehicle passed inspection (in another state) a month ago... I think I can handle this myself, however, I have questions. Vehicle is '99 Cherokee, 4.0, AW4, 4WD (not full-time.)

1) Parts store said that they have both semi-metallic and ceramic pads in stock, for not much difference in price. Counter guy recommended semi-met for heavier duty use because "they handle the heat better." I thought ceramic was supposed to be better all around. True/false?

2) There are apparently two options for rotors, depending on wheel stud length (?!?!?!?) Is there any way to tell what I need before taking the vehicle apart, or is this one of those "just get in there and do it and then go back to the parts store" things?

3) What tools do I need to remove the calipers? Anything special? I'm assuming that these are single piston calipers, would it be worthwhile to pick up a "hardware kit" as well if they have it in stock, or do the sliders typically not require replacing at every pad change? (sorry, haven't even got a shop manual yet - wasn't anticipating having to do any work like this right up front.)

4) I'm assuming that being 4WD the rotors just slide off the studs once I have the calipers off, yes?

I'm supposed to be getting the vehicle back from the shop tomorrow because I told them that I'd take care of the brakes myself (~$150 for parts sounds a lot better than $400 to pay someone to do it, especially since I ought to have all the tools.) I'm going to have to get right on this because the local constabulary has already hassled several other people in my neighborhood about stuff like this (e.g. having a vehicle with no inspection sticker) so I'm anticipating buying the parts tomorrow.

thanks for any help you can offer...

Cherockee

Maybe take it to another shop and get a second opinion.

I don't want to send you on a wild goose chase, but I seem to remember there being a recall on front rotors a while back. There's something mentioned about it here:
http://www.jeepforum.com/forum/f11/m...-recall-20620/

Bustedback

The difference in the rotors are if you have cast or composit rotors. Composit rotors will have a thin hub mounting center, where the cast are about 1/4 of an inch thick at the hub mounting area. Simple hand tools are all that is required to remove the calipers and the rotors should just fall right off, they may need some help with a mahher if they're rusted to the hub. You do NOT have to bleed the brakes if you're only replacing the pads and do not open the hydraulic system up to air. I have no opinion on what pads to buy though.

rand4x4

Rotors just slide off, Just get new rotors at part store they where 28 bucks.
I have never seen a inspection say you need new pads. Where the making grinding noise. Lenght on studs should not matter unless the new rotors are thicker on face.
Sounds like a bunch of BS from both guys.

DaveVmax

basic hand tools, wrenches, socket set, anti-seize, c-clamps or channel locks... should have that stuff anyway if you own a jeep.


just buy the semi-metallic

maddogs1965

I am like you, i figured the ceramic pads were the best you could buy, at least that's what i have been told bye my local Napa .....

As far as removing the brake caliper's, no special tools needed, i have a Dana H.P. 44 in the front of mine, so i cant tell you what your stock Dana 30 is, but it will either need a allen wrench or socket to remove the 2 long bolts that hold the brake caliper to the mounting bracket.

The rotor's should be a knock off once you remove the brake calipers., but unless they are grooved real bad from the brake pads being metal to metal on the rotor, or the rotor has glazed over, or it has heat checks or cracks in them, you should not need another set of rotors.

Once you have the brake caliper off, you will need either a big C clamp or a big pair if vice grips to push the piston back into the brake caliper too be able to get enough clearance to re-install the new thicker brake pads over the rotor again. I always use the old brake pad to pinch in-between the piston and the back of the brake caliper so nothing can damage the piston.

N8N

So the calipers use a slider that looks like the ones on my dad's '73 Chevy pickup then if I am understanding the description correctly? If that's the case I may go ahead and order the hardware kit if I can get it. I will go ahead and bleed anyway as I have a pressure bleeder, so no danger of crapping up the master cylinder by pump bleeding. Anti-sleaze, I have that in every toolbox... I have owned several Studebakers so I am well aware of the desirability of using anti-sleaze on damn near everything (wonder if it's good on pancakes?)

The way it works in VA is unless the guy cuts me a break and does something he's not supposed to, I get a rejection sticker and have to bring the vehicle back to the same station for reinspection (and the information is reported to the state,) so there's really no fighting the need for new brakes unless/until I get the rotors and pads off and measure them myself and find them not outside the wear limits. I'd rather go ahead and get new brakes anyway if it's in any way questionable, although I'd as soon do it at my leisure rather than being forced to do it... but c'est la vie...

captainofiron

I really like ceramic brake pads. they seem to stand up to heat/wear better

N8N

Well something just happened that I am not gonna complain about... showed up to pick up jeep - I'd asked them to do a safety inspection, oil change, chassis lube, and just look it over for any problems (now I knew about some of them already, mostly having to do with fluids that looked like they were due for a change, sketchy belts, screwed up battery and cables, etc.) got to the counter and I asked the service writer "OK, what do I need to do here" and he said "well, your front brakes failed, but I just went ahead and put a sticker on it. It's not metal to metal so just fix it as soon as you can."

I guess I must look like I know what I'm talking about

So given the above, this is now somewhat less time critical as I have all the appropriate paraphernalia that the local constabulary requires, I have the option of ordering online. Looks like Performance Friction pads are relatively inexpensive (cheaper than the options given to me at my FLAPS,) are those good? Or should I get something else?

thanks!

maddogs1965

I would stick with the ceramic or semi metallic pads....one thing i have learned in my 20 years of wrenching, you get what you pay for, if something is cheap, its a cheap part. The cheaper pads will work for you, but they just don't last as long as the expensive set does...

xjsnake

Go on rockauto or napa and order name brand pads and rotors if you want an upgrade (I like to put new rotors on any vehicle I buy so I know they were done correctly). I've got autozone's duralast pads and rotors on my xj currently due to a lack of funds and they work well with no real problems but I know people on here like to complain about them.

While you are tearing brakes apart, look into doing a rear disc swap, saves you from working on the drums ever again.

mr white

I like ceramic pads, they seem to stop better, especially when you get them hot.
I've always had luck with checker/oreily's no name brake parts, they are like brake best or some ****.

N8N

OK... so I finally got it up in the air today and I've decided since I got my sticker that I am going to order Centric pads w/ the e-coat, rather than get ones from the parts store (which aren't coated, but are about the same price) to see how they do. However I'm going nuts trying to determine what is correct.

Parts store wants to know the length of my lug studs which are 1-1/2" measured from the hub flange (with the rotor off.) That was the longer of the two options which I'm pretty sure means that they're factory cast rotors (they are cast, don't know if they're original factory or not. Hub area of rotors is pretty thick.)

I also found this site:

http://shop.blackmagicbrakes.com/Ear...-477-67022.htm

it says that the rear brake surface to hub mating surface is 3" for "early 99" and 2-3/4" for "late 99" mine are about 2-3/4"

because I'm ordering online I just want someone to double check me and make sure I'm right because my brakes are pretty thin and I'd like to go ahead and get this done. Please correct any of the statements below if they are incorrect.

- All-cast rotors were used on mid-99 and newer XJs, *earlier* ones used the "composite" rotors.
- All-cast rotors have a hub thickness of a little less than 3/8", the composite ones are noticeably thinner.
- If I have a '99 XJ with all-cast rotors, I should order replacement rotors for a 2000 to alleviate any confusion.
- The all cast rotors have a nominal height of 3.07" and the composite ones have a nominal height of 3.22" (this is how the Centric ones are spec'd)
- The all cast rotors use lug studs with a length outside the hub flange of 1.5", the composite rotors are shorter (this is how the parts store catalog differentiates them)
- The all cast rotors have a inside friction surface to hub mating surface distance of 2.75"; the composite ones have the same measurement at 3.0"

My build date is April 1999 so that really doesn't help with the early/late thing - it's a little into the second half of the model year, but not by much.

thanks for any help that you can offer! (and please confirm/correct my assumptions so I can get my new brakes on the way.)

BTW just for the record, the brakes AFAICT are right *at* the wear limit and not dangerous, so I don't feel irresponsible continuing to drive it. I'd get the cheap parts store stuff and fix it today if I thought that they'd go metal to metal and/or the pads looked thin enough to come off the backing plates between now and next weekend (just thought I'd throw that out there; sometimes people get all up in arms about people driving "unsafe" vehicles.)

BTW now I'm just curious. Let's say I was replacing my hubs at the same time, hypothetically if I had a vehicle with composite rotors and replaced both the hubs and rotors with parts from a vehicle with all-cast rotors, would everything else bolt up and work correctly? Or are there other parts that changed between the two types? I'm also assuming that the all-cast rotors would be more desirable, being stronger - but that is just an ASSumption.

A_Jeepr

2/32"s is the minimum for pads in the state of Virginia. (I failed 3 cars last week for it lol)

look at the rotors, it they are grooved, replace them, if not, no need.

Ceramic gives better wet braking performance, but they put off a ton of dust, and tend to be noisy.

Semi-metallic is the best all around material.

2 rotors and pads should cost you only $65 or so.

Its only $1 for re inspection if you new the reject sticker. And if an inspector is caught not following the rules the business looses its licence too. So most places won't cut you a break at the expense of possibly loosing their job.

N8N

I hear what you're saying... the pads are right about at 2/32 and the rotors are right at whatever the minimum wear spec is (I've already forgotten, but I checked it) and I wouldn't call them "grooved" but they'd certainly be way below spec if turned smooth. So I ain't gonna fight it. And I hear you on the inspection thing, the guy didn't have to cut me a break and I didn't ask for it but he did anyway, so as soon as my new parts come in I'm going to get them on because he did tell me they needed to be done and apparently trusted me to do it, don't wanna let him down and put him in a bad spot. It'd be done already if it weren't for the mid-year rotor thing; I had to actually take the thing apart before I could even order the parts. But anyway I'm just kinda **** retentive, I'd rather do something myself and use "great" parts rather than let someone else do it and use "good" parts. That and I am a big believer in anti-sleaze and also hitting every threaded fastener in the area with penetrating oil while I'm working on something, whether I'm removing that fastener or not.

That, and I found crusty gunk on the zerk fittings which annoyed me because I paid for a LOF at the same time as the inspection. (this is why we do things ourselves.) And of course my grease gun was empty and frozen, having been out in the shed. gotta find some more grease now...

I have Raybestos (I think?) ceramics on my pickup truck and have noticed no downsides at all... but I already ordered Performance Friction carbon metallics and Centric e-coat rotors from Amazon (!?!?!?) because their prices were in line with whatever I was going to get from Carquest up the street and surprisingly cheaper than Rock Auto etc. once you factor in free shipping. Hope I guessed right on the rotors or I will be making a run to the parts store again anyway...