CommanderXJ

I've owned the car for almost three years now and I am going onto my fourth set of rotors now. I've heard jeeps go through rotors a bit more often than regular sized cars but it seems a bit too often to me.

I've also noticed on the inside wall of the passenger tire that there is some type of oil that pretty much blasted the tire. Its not brake fluid...looks much thicker so I am thinking it might be gear oil.

Beyond that she is at 140k miles and I'd like to do a tune up. Any ideas on what I should check for.

nickxj94

Dadgum that's alot of rotors! May check to see if your rear brakes are working, and the oil is probably gear oil may have a axle seal leaking, or someone got grease on it from greasing ball joints maybe

ZINGGG

Where are you getting these rotors from?

Bustedback

Spend a few bucks moore and buy American made rotors, the crap from China does not stay true for very long. Also make sure to hand torque the wheels to spec, an impact gun will ruin rotors in a heartbeat. Make sure the rear brakes are adjusted properly too.

JeepsAreForSpeed

Maybe your back star wheels are not adjusted so your front brakes are doing all of the work? Or your pads are too metallic thus wearing the rotors. I use to cheapest organic pads out there for the front they wear quicker but the rotors dont.

Carl48

The oil on the tire could be gear oil leaking out of the axle...if it smells like sulphur, it is gear oil...no mistaking that smell. Also, make sure the pads aren't dragging on the rotors, uneven wear on the pads is indication that they are dragging...the calipers should float on the bushings...lubricate inside the bushing boots with hi-temp silicone dielectric grease.

DFlintstone

If that front axle seal is leaking, you might want to top off that front differential, right away. A Spendy hassle if you cook that.

Do you regularly deal with a lot of down hill? (I do, I have lots of old rotors, and a bucket or two of old pads in my barn), (I solved the problem though)

Also, easy to check....where the pads ride on their holder, check that there is not and groove/slot, or wear that will hamper the pad from freely moving back off the rotor. When braking there is allot of force there. (that would be where the pads ride/brace against the caliper mounting bracket)

Last, I found the rings in my calipers seem to have swollen over many years to the point where the piston could not freely retract due to being too tight. Took me a bit to get that one, I would have expected wear, and looseness, or leaking. Now with new calipers, if I give the wheel a good spin, it will make over 1-1/2 revolutions. (a GOOD spin!)

Also if you have the right place...when you have run a bit at speed, stop without using the pedal. Slow down, then stop with the E-brake, then check the Rotors for heat. Mine are still plenty warm, but not hot. Heat of course means that it's dragging.

CommanderXJ

I replaced a bad brake caliper on the passenger side about a year ago bc I noticed my brake pads got to the point of it grinding up against the rotor which caused it to fail the second time (I'll take the fault for that one) but I don't see any problems with either side this time so that's why I was curious. I asked some fellow Cherokee owners and a few have told me that they go through rotors more often, but I guess I'll need to buy better rotors.

I haven't checked the gear oil in some time and will probably get around to doing that this weekend. Been so darn busy with work and all this week lol. If my front axle seal is bad, would there be some gear oil right by the tie rods ends as well? I noticed the passenger side tie rod end (bushing) looked damp while the one on the driver's side was dry.

DFlintstone

I would look for seal leakage there where the axle comes out to the U-joint. Myself, I have a small leak somewhere in my power steering that keeps most of that ^ a little wet. Good to top off the differential anytime, and if it takes a bit of course that might be a clue.

MtnHermit

Well if you look at the caliper, it has to slide in/out on those spring gizmos, if it doesn't the rotor and pads will suffer. May be time to replace/repair the calipers?



Clearly a half a$$ cheap solution compared to inner/outer pistons.

wjnfirearms

Hermit is right about the caliper sliders. They must be free to move and commonly get rusted in place. They will cause braking and brake wear issues when they seize up. The fix is to tap them out, clean out the guide holes in the caliper, grind off the rust on the sliders or buy new ones, and grease them before they are replaced in the caliper. Replace the boots if they are damaged. They must be checked each time you service the brake calipers as this is a common problem and is not limited to Jeeps only.

I've never had rotor issues like you have with any of the 4 XJs we've owned including the 2 current ones. You didn't mention if there is any issue with hard braking as if there is too much pressure being put on the rotors during braking. That could be an issue with the master cylinder or the proportioning valve. Metallic pads do wear out rotors more quickly than other compositions, but not 4 sets in three years.

You may want to check the entire braking system more thoroughly first. I'd also recommend switching to another composition as mentioned. I use ceramic pads on my '98 now. They are more expensive (I have Duralast C Max pads on it now), but have several benefits over organics. They stop better, are more quiet, and produce much less dust. They also don't tear up the rotors like metallics.

wjnfirearms

Oh yeah...as to the oil on the tire, that pretty much is a sign of a bad axle seal for sure. The procedure to fix is to remove the hub & bearing combo, remove the axle, and replace the seal. This will stop the problem. I would recommend not procrastinating on this as you not only risk running the front differential out of lube which will trash the gears and compromise the bearings not being lubed properly, but you risk getting gear oil on the brakes and you know what that will mean. Compromised braking.

A general proper tune up on the 4.0 would entail plugs, possibly a wireset depending on age and condition, distributor cap & rotor, air filter. Remember that just because the plug wires are still flexible and intact on the outside doesn't mean that they are still good. The center conductor can get brittle with age and develop cracks which cause the spark to have to jump across and compromises the spark's energy. It they are more than 5 years old or you don't know when they were installed prior to you buying the XJ 3 years ago, I'd consider replacing them. Don't cheap out on these. Good wires cost, on the average, $30+ depending on brand and where you buy them. I always liked our Duralast and Bosch brands we sell because they work and also have a lifetime guarantee. If you have a brand preference already, go with what works for you.

MtnHermit

Do you know of a service bulletin on maintaining those sliders?

I'll be replacing my pads in the next few weeks and the calipers will be off, so good time to service that part.

Thanks

car5car

I was diagnosing caliper once, I drove about 50 mph, then switched gear in neutral and waited until car stops w/o using brakes. Then I checked if rotor was hot.
Not sure if you can find a road for that test.
You can rebuild calipers, I used to do it on my bikes. They have dust boot and one square O-ring. Remove piston by compressed air (keep it away from your face) and use sand paper to clean piston.