Front brakes pulsate

[Ry' N Jen]

Good day,
As of a few days ago, the front brakes pulsate when de-accelerating.
I removed both front wheels and visually inspected both the rotors and brake pads. The brake pads have about 70% "brake pad" left on them(both wheels) and the rotors are free of any irregularities (no grooves,etc.)
Hard to tell if they are warped, as I did not remove them from the hub/spindle. I have a feeling that they might need to be turned (machined)
as that is whats causing the pulsating when slowing from 30+ MPH.

Now, I do not yet have a factory service manual. Are the wheel bearings re-packable on a KJ or are they like lets say a Ford F350 where the whole bearing assembly is a non-serviceable cartridge that you have to replace with a new one once you remove the old one?

All comments welcome

Creers
Ryan

 

[_UnLiMiTeD_]

sounds to me like the rotors need to be machined

 

[Corwyyn]

This is from my '03 FSM, don't know if they have changed anything for the later years. Looks like they are a non-serviceable unit:

HUB / BEARING
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the tire and wheel assembly.
(3) Remove the caliper adapter (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPERS - REMOVAL).
CAUTION: Never allow the disc brake caliper to
hang from the brake hose. Damage to the brake
hose will result. Provide a suitable support to hang
the caliper securely.
(4) Remove the disc brake rotor (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/ROTORS -
REMOVAL).
(5) Remove the wheel speed sensor (Refer to 5 -
BRAKES/ELECTRICAL/FRONT WHEEL SPEED
SENSOR - REMOVAL).
(6) Remove the bracket securing the wheel speed
sensor wire.
(7) Remove the axle shaft nut. (if equipped with
four wheel drive)
(8) Remove the three mounting bolts for the hub/
bearing assembly.
(9) Remove the hub/bearing.

 

[moparman]

Warped rotors are hardly ever just warped rotors. Unless you are riding the brake, pulling trailers, driving in the mountains, taking your Jeep on a racetrack, etc., what made them get that way? Is the pulsing present at all times and all speeds? If it is intermittent, especially after highway driving, that is a heat problem. The brakes are dragging a little. Look for sticking calipers. At the least, clean and lube the sliding areas on the outside of the caliper. Lithium or synthetic grease should work.

If the pulsing is present at all times you still have to check the calipers, the piston will stick internally and need rebuilding or replacement. Usually one side will be a problem and that side's pads will be worn more. You have inspected the pads but were you able to see the inside ones? That would be the clue to caliper problems.

If the rotors have gotten really hot, machining them is a temporary fix as they will be prone to warping again.

 

[06Liberty]

I"ve always heard that if you hit a puddle or spray the rotor with water like a carwash might do when the rotors are hot, then that could very easily make them warp and then you get the pulsating....is that true? I always wait till they've cooled down before I wash because of this.

 

[JeepJeepster]

Had my rotors warp around 15k or so. Had them machined and theyve been since, 28k now.

 

[2003KJ]

Mine are warped as well, and starting to squeal as of late....looks like i'll be doing a brake job here in the near future.

Mine have been warped for quite some time, and I can easily see how. The KJ does weigh a substantial amount for a SUV of it's size. Thus, it takes much more to slow the beast down, and Chrysler isn't exactly known for their high quality rotors from factory (had a big problem with warped rotors on the WJ's). I'm very easy on my brakes compared to most (always pump the brakes never riding them for too long, start slowing down far in advance when possible as to avoid always slamming the brake pedal down etc etc). But the way I see it is, i've got 46K on the orig. pads and rotors. Thats not bad at all for an automatic vehicle that weighs a lot.

 

[Epic-yoda]

They are warped I just did a brake job and I allready warped one 3 weeks later after having them cut. I went on a trip and there were lots op down hill I must of over heated one and hit a puddle or something but now its making a noise like its warped again. I am going to buy the drill sloted ones.

 

[sevenhelmet]

This brings up yet another reason I like the manual ******. I downshift for engine braking a lot which saves a LOT of wear and tear on the brakes. 62K and they're fine although I think it had a brake job at 30K (not sure since I didn't own it then.)

 

[2003KJ]

This brings up yet another reason I like the manual ******. I downshift for engine braking a lot which saves a LOT of wear and tear on the brakes. 62K and they're fine although I think it had a brake job at 30K (not sure since I didn't own it then.)

Agreed on the manual ******. My previous car was a straight drive, and I got to about 65K before it needed a set of front rotors and pads. I promptly traded it in for the Jeep at that point

 

[OldBlue]

The KJ does weigh a substantial amount for a SUV of it's size.

Isn't that the truth!

 

[Corwyyn]

This brings up yet another reason I like the manual ******. I downshift for engine braking a lot which saves a LOT of wear and tear on the brakes. 62K and they're fine although I think it had a brake job at 30K (not sure since I didn't own it then.)

On my '03 with the 42RLE I lock out the overdrive going downhill and get decent engine braking, enough were I don't have to touch my brakes but a couple of times while everyone else is on and off theirs all the way down.

Just changed my front rotors and pads this afternoon, now I'm resting up a little before I go out and do a road check. I had changed the pads only about 15k back, but I went with the semi-metallics that time and they were not impressive. Went back to the ceramics this time, we'll see how much better it is...

 

[2003KJ]

Mine does the same, but only at high speeds. Read somewhere that after fitting new tires or takin of the rims you need to torque the nuts all the same, with a torque wrench. Seems if you overtighten them the rotor get's more easily warped...

This is true, which is why its important to torque them all to the same setting, and go back and check them again after about 20 miles of driving.

 

[seriouse]

Mine are warped as well, and starting to squeal as of late....looks like i'll be doing a brake job here in the near future.

Mine have been warped for quite some time, and I can easily see how. The KJ does weigh a substantial amount for a SUV of it's size. Thus, it takes much more to slow the beast down, and Chrysler isn't exactly known for their high quality rotors from factory (had a big problem with warped rotors on the WJ's). I'm very easy on my brakes compared to most (always pump the brakes never riding them for too long, start slowing down far in advance when possible as to avoid always slamming the brake pedal down etc etc). But the way I see it is, i've got 46K on the orig. pads and rotors. Thats not bad at all for an automatic vehicle that weighs a lot.

This raise another question. Are there a big brake setup that can be installed in the kj?

 

[2003KJ]

This raise another question. Are there a big brake setup that can be installed in the kj?

That, I am not sure of. If there is, I would probably look into it, as a way of reducing the work load the brakes have to do to stop the ole beast.

 

[Mangate]

Mine started pulsing around 10,000 km, but now at 42,000 they seem to have fixed themselves. It's worth taking the rotors off just to make sure a piece of rust or other material isn't trapped behind causing them not to sit flat against the hub.

 

[seriouse]

That, I am not sure of. If there is, I would probably look into it, as a way of reducing the work load the brakes have to do to stop the ole beast.

The problem with my KJ is that it have drums in the rear and theyre adjusted like they should but my rotors need resurfacing at least every 6-8 months and they can only be ressurfaced about one time according to specs of the rotor. That is why i was asking about an upgrade for the front brakes.

 

[Ry' N Jen]

Good day,
Ok, I kind of figured that the rotors had warped to some degree.
Now it's just a matter of researching the best possible replacement rotor and brake pad combo.
I wouldn't mind something along the lines of either grooved and cross drilled
or just grooved. (Seeing that cross drilled rotors have been known to crack after they warp.) Of course a whole big brake setup would be nice. Especially for towing applications.

 

[jeepgirl0385]

My brakes had warped, they didn't make noise, but they certainly pulsed while stopping. I had also had issues with my tires feeling like they were out of balance at highway speeds. That seemed to subside when I got new tires, but then it got bad again. it turns out when I got the brakes replaced, the tire vibration on the highway went away too!

But what really ***** is the brakes are new (front rotors and pads) and they have already seem to have warped again.

I try to be real good to my brakes, not riding them, trying not to brake when I have just gone through a puddle etc.

Hopefully I can find some other sort of brake rotor than these darn DaimlerChrysler ones.

 

[JeepJeepster]

well, you dont want to replace a rotor with the same rotor if the first set of rotors warped.

Everyone seems to like the napa rotors but I may go with brembos.