Pulsating brakes

1-2 in thickness or warp?

If it's the ABS sensor you will get an antilock feedback (pedal vibration) on slow speed stops just as you come to the stop. If the ABS isn't kicking on then it's not the sensor. If you are getting ABS feedback then check the sensors for metal fragment buildup and wipe them down with a rag. (all four)

Just be be certain, by "pulsating brakes" you mean seat of the pants or do you mean pedal vibration.

It doesn't take too much warp to cause problems, but usually that can be felt even on a higher speed decel.

Other thought is how's your engine doing? If it's stumbling around at low rpm with load then that can also cause the same seat-o-the-pants feeling.

did you have your tires rotated or new tires ... they may have torque the nuts to tight .. it is a cause of warped rotors...GC have a history of getting warped rotors .. there is always a discussion of the quality of the rotors or the tire man ... each is hard to prove ...

Thanks guys it is a Pedal vibration at low speeds, so I will check those sensors, and i know the ABS is working correctly After I have check the sensors I will torque the wheels.

One other thing. On my 95ZJ, the ABS computer is located up front by the air cleaner and is subjected to a lot of road grime and water. The connector will eventually become contaminated. In order to fix this you disconnect the battery, remove the connector, and use a spay contact cleaner to clean the connector. (be careful not to get cleaner on paint! Contact cleaner acts like paint stripper) I used the bottom half of the filter box as a little sink, lined with plasic and paper towel.

After you are done, put some dilectric grease on the pins and connector. Dilectric grease is the same stuff used on sparkplug boots.

thanks. OK I am going to start with re-torqueing the wheel nuts, if this does not work then I will check the ABS Senors. So then my next question is do you need to remove the rotors to get at the sensors?? If so, what=92s involved in removing the rotors. It looks like they have O-ring at the center of the rotor where it backs up to the flange. Do the rotors need to be persuaded to come off? Then once I get the rotors off if need be, is there a spec for gap of the sensors or is it fixed and just need to make sure there is no obstruction between the sensor and the pick-up

On the front wheels you should be able to see the sensors and tone ring by looking where the axle comes through the steering knuckle. It's a tight fit. I use a cloth rag on a stir-stick (popsicle stick) or some such. Just follow the wire.

I think you have to take the rear discs off. My rear brakes are drums so it's different than yours. Jeep went to rear discs in 95.

For rear discs they can be held in by the emergency brake. All depends on the wear.

ABS sensor looks like it mounts inside.

you've probably made some high speed stops and then kept the brakes on at an intersection ... with a lot of heat in the rotors you will get a transfer of some of the brake pad binder resin onto the rotor and you can also get hard spots in the iron from the heat. hard spots won't be fixed by turning the rotors.

*********** all-important transfer layer As stated above, the objective of the bed-in process is to deposit an even layer of brake pad material, or transfer layer , on the rubbing surface of the rotor disc. Note the emphasis on the word even, as uneven pad deposits on the rotor face are the number one, and almost exclusive cause of brake judder or vibration.

Let's say that again, just so there is no misunderstanding. Uneven pad deposits on the rotor face are the number one, and almost exclusive cause of brake judder or vibration.

It only takes a small amount of thickness variation, or TV, in the transfer layer (we're only talking a few ten thousandths of an inch here) to initiate brake vibration. While the impact of an uneven transfer layer is almost imperceptible at first, as the pad starts riding the high and low spots, more and more TV will be naturally generated until the vibration is much more evident. With prolonged exposure, the high spots can become hot spots and can actually change the metallurgy of the rotor in those areas, creating ?hard? spots in the rotor face that are virtually impossible to remove.

*************

best bet is to replace the front rotors and pads - get the kit which includes the caliper pin boots and lube - not hard to do at all. I wouldn't go for the real high speed metallic pads (it's a Jeep, not a Corvette) but spend enough to get pads that won't shed dust bad.

when you get it all together, bed the brakes in properly

google brake bedding-in procedure and you'll find some more good instructions.

total parts should run $120 - 140 + your labor

reboot

Heh.. I got pulled over while doing that on a back road. :)

Told the cop that I couldn't sit there for too long or I'd screw up the rotors and he let me go.

Yep. Rotate front to back and see if the vibration moves.

The sensors on my ZJ are metal with a fairly strong magnet as the head end. Typical FET (Field Effect Transistor) similar to the CPS sensor. I've found they collect brake dust and other fine metal debris. Once they have 1 mm or so of stuff built up the system tends to be twitchy at low speed. I just wipe them off with a rag when I'm rotating tires or checking brakes.