I need someone with a doctorate in TJ brakes. I 1997 Jeep TJ Sport. Was doing a little off roading and thought we might have boiled the brake fluid bc the brakes got a little squishy. When I would press on the brakes, they were there, but would get a bit soft and the ABS would kick in at the end of the braking and starts vibrating the brake pedal in the last few feet of a little harder than normal stop. Took it to a fellow off roader friends house and replaced the brake lines bc we were there. Flushed the old fluid out and added new fluid bleeding the brakes from the furthest to the closest brake. brakes a little better, but again, at the end of a harder than normal stop, the ABS kicks in and the pedal vibrates a bit until it finally stops. ABS brake/speed sensors possibly? I’m not a mechanic, rather a guy trying. I just don’t know what to do but send it to the shop. Ever hear of something like this. Thanks to anyone passing on any wisdom to others so we can share the wealth of knowledge to other down the road, pun intended.
Pull the ABS fuses and try the hard stops again.
I like the direction you are going...cheapest 1st.
My son took it to work, so it’s the first thing I will do tomorrow morning and let you know. Thank you!
Well, you did ask for someone with a doctorate in breaks and you got him.I like the direction you are going...cheapest 1st.
That’s what I hear from Jerry. Thanks again Jerry B.
If Blaine can't get your breaks straightened out no one can. Seriously. None better.
Ok, when I pulled the fuses, the brake felt normal. I put in a new fuse in, the brake problem came back.
Now we know you have some sort of ABS related issue. Inspect the sensors and their harness to each corner.
The other thing is when you say normal, is that normal with zero difference in pedal feel or is there some indication that they may be a little spongy still?
The break feels 100% normal. No spongy feeling. They actually feel better than I can remember them feeling for the last year.
Inspect as in remove and clean and reinstall and/or visually insect the wires and harnesses?
Check it all including the tone rings if you can. I don't know how much will be visible by pulling the rear drums but you should try and make sure they are in good shape. Good news is if you can live without ABS, you know how to bypass it until you can find the problem.
The tone rings are the serrated discs that are attached to the axle. Next to the tone rings is a small magnet, the magnet senses the speed of the rings by seeing the teeth pass in front of them. The magnet then produces an electrical signal in the form of a wave which is sent back to the ABS controller (or possibly the PCM, I'm not sure on the TJs) to calculate the speed of each wheel relative to one another. The computer then compares all 4 waveforms and, if it sees a difference between them, activates the ABS system because it thinks one or more wheels are locking up.
The tone rings should be nice and sharp all the way around without any damage or crud in them, and the sensor shouldn't have any nicks or crap on them.
Ok, I have a BASIC understanding after watching a video. I will take a look tomorrow morning.
I will check out tomorrow. Thank you for taking the time.
Question for Blaine.
On other vehicles I've owned panic, or emergency braking was supposed to trigger the antilocks to pulse, preventing the tires from locking up. Is this system different oram I not understanding the problem correctly?
On other vehicles I've owned panic, or emergency braking was supposed to trigger the antilocks to pulse, preventing the tires from locking up. Is this system different oram I not understanding the problem correctly?
You are correct for panic or emergency braking. I don't read his as panic stops since he describes them as slightly harder than normal and an implied change from previous brake feel.