Brake pad life on heavier XJ's.

[blistovmhz]

I've got an XJ 44 with 03 KJ discs on the back of my roughly 5000lbs (loaded) XJ on 35's. I'm pretty hard on my brakes, but the life I've been getting out of the rear pads seems a bit ridiculous and I'm trying to figure out if my rotors are to blame (wrecker rotors), or if this is just normal for this weight.
I just replaced the pads and calipers over summer. I figured the calipers weren't retracting, causing the pads to burn off (did have a few times where the calipers froze). Got under Jeep today for some other stuff, and noticed the pads are completely burnt off again.

I don't drive much. I work from home so the only use the Jeep gets is to the grocery store, and out wheeling once a week. I can't imagine that this is normal wear/tear for a rig my weight, with so little mileage. This'd be like 1 month of normal use for anyone who has to drive to work. Also, the first and second sets of pads burnt out just as fast when my rear calipers were barely engaging (before I figured out the prop-valve wasn't letting enough pressure to the rear). Now that's fixed, the pad life seems about the same, I just stop WAY better. The second set of pads were mated to a new set of rotors as well, and no difference (though that set was drilled/slotted, which may have helped chew the pads with mud/silt).

I wouldn't care that much except that CHEAP pads locally, start at $140 a set. Still crap, but less cheap start around $170. Seems like a waste of money for 4-6 months of occasional driving.

Rotors themselves LOOK good, but it's entirely possible they're ****ed in a way I can't visually confirm. Bad rotors make sense?

P.S. They brakes work ridiculously good. I can lock up all 4 on 35's on dry pavement easily.
P.P.S Keep in mind, my rig isn't much heavier than a stock KJ anyway.

 

[ftwelder]

based on your brake system posts I would say your brakes are more biased to the rear. Correct street bias is pretty poor for off-road due to excessive front bias. Brake hard in the middle of some dirt turns and if you don't suddenly go straight I may be correct. It takes a lot of thinking about tire slip rates to really feel too much rear brake on pavement but it will kill pads.

 

[blistovmhz]

I'd considered that, but it doesn't make sense to me for two reasons.
1. First two sets of pads weren't even being used. My combo-valve was all messed up. With the Jeep on stands, chuck it in first (manual) and let it idle, and I could barely get the rears to stop. I eventually traced the problem to the combo-valve/p-valve. Removed the prop internals to test (equal pressure to front/rear) and then had zero problem locking up both front/rear at the same time. The rears do lock up a little bit earlier than the front now, but the pad life was shit even when the rears weren't working.
2. Stock Liberty couldn't have had this problem.

My fronts work damn hard, and in a bit over 2 years, I'm only on my second set of pads (just installed 4 months ago), and bear in mind that for the first 18 months on those first front pads, they were doing 100% of the braking. Just seems strange to me that the fronts could be doing all the work for that long, and still out-live the rears by over a year, when the rears weren't even able to stop my truck from idling.

 

[trippled]

Are you using cheap pads? They never last if you are. Have you tried getting brake temps after a drive? I use an ir temp gun at work, if I shoot the wear surface of the rotor after normal city driving, I usually see about 2-300 degrees f. More youre either driving the crap out of it or you still have calipers hanging up.

 

[blondejoncherokee]

Get a prop valve and fix the rear bias. Replace calipers as needed.how many miles are you getting from the rears?

 

[Johnnie Walker]

Centric Pads and rotors.

 

[blistovmhz]

There are no "cheap" pads in Canada. The shittiest Chinese pads start at $125 (+12% tax).
I've run Napa's premium's as well as some shitty powerstop amazon specials. Both burned off in under 5000km (probably closer to 3000).

The rear bias definitely WASN'T the problem before, as the rear wasn't getting any fluid pressure, but still blew through the pads (with brand new, shitty rotors). Then I put the stock rotors back on with some new napa premium pads and new calipers, and 3000km or so later, they're completely gone.

Just ordered a set of GreenStuff and Centric Premiums. Hoping to discover that all pads sold in Canada are just absolute shit. Also going to try to stay out of the silt (though again, the fronts are holding up very well comparatively).

 

[Demonoid369]

Are both pads worn evenly on each side? Or is one thinner than the other? I'd swap the calipers and see and get new rotors

 

[blistovmhz]

Did swap the calipers. Brand new last time I swapped pads.
Pad wear is fairly even, but a little slanted. IIRC, the top inner and bottom outer have the most wear, but it's barely perceptible, and identical on both sides (of the truck).
I've never had pads wear like this without there being an obvious fault, but checked rotor temp (rear is 40 degrees lower than front). It very well could be that the rears just hold on to more silty junk (we wheel in a lake bed fairly often, and it's known to eat bearings, so I assume pads as well).

Either way, will have the new Greenies and Centric Premiums in a few days and I guess I'll just keep a real close eye on it.

 

[blondejoncherokee]

Do you have the rear line plumbed to the front part of the reservoir and vice versa for the front ? maybe you plumbed the hard lines wrong.



greenstuff will wear faster probably, performance pads like that are made to stop well, not to last long.

3000 miles is insane man. Do you drive like an asshole? JK. something is not right.

Maybe the master is bad? did you adjust the booster push rod ? maybe the rears are always dragging if the pushrod is always a little bit in ?

 

[blistovmhz]

All good idea's, but all explained already.
The rear wasn't even able to stop the truck from idling on stands in 1st gear, while standing on the brakes. The fronts would easily lock up on dry pavement, but rears were doing nothing for the entire last set of pads. I installed the new Napa pads when I removed the front/rear isolation, and due to my weight distribution, all 4 lock up now on dry pavement at roughly the same time. Fronts are still working a litter harder, as they're 40d hotter than the rears. This is the thing. The rears being colder than the fronts, either confirms that the problem is not from regular braking (suggesting silt or something) or just real extra shit pads, or the rotor is just eating them. This is why I'm going with new rotors as well this time.

Know what sucks? A set of bargain basement pads and rotors here would cost me $240. Or I can order the greenstuff + centric premium from the US for $125. Goddamnit Canada.

And yea, I'm sorta hard on my brakes, but the key is that I'm harder on the fronts than the rears, and the fronts are lasting me 2-3 years to a pair of pads. I would blame the switch to the V8 and auto trans (less engine braking now), but problem was just as bad with the 4.0L/AX15.

 

[Demonoid369]

Maybe look for leaks, axle and brake fluid will eat pads. You say kj discs, are they slotted or dimpled? Those can hold grit/silt/etc.... And eat pads also

 

[cp2295]

Did you lube the caliper slides? And the backsides of the pads and clips? Was the piston easy to compress? If not it needs new calipers, make sure and lube it up. Buy centric 105 or 106 series pads, they are great. I put them on HD rigs at work that burn thru pads. Is your MC lines hooked up correct? You may have the lines hooked up wrong and the pressure for the front calipers is actually going to the rear.

To me it sounds like yes your prop valve and MC lines are hooked up right, but i would make sure. And def get new rotors just plain ones.. No drilled and slotted, those can make your brakes last longer if its a street only rig but with wheeling it and all i wouldnt try it again.