JyRO

Alright - My glitchy computer is now working with DTR again. Its been a long time, but I'm back!

As for my ABS issue. I searched and from what I've seen, nobody has exactly the same problem. Hyper's problem was as close as I've seen, so I'm wondering if you guys have some guesses, and/or could tell me if you think his fix will work for me.

Here's what's happening. Mainly when towing (because I don't drive it without towing much anymore), I try to anticipate red traffic lights, and slow early and gently at stops signs or basically anywhere.

I made the first set of front brake pads go 85,000 miles like this. And the tires went 100k.

But now, when I'm almost to a stop and have slowed very gently and still gently coming to a stop, just before I stop (maybe at like 3 to 5 mph) the ABS unit kicks in (you can actually hear it running under the hood) and I of course can feel the pedal pulsing.

Not only can I hear it and feel it, but it causes the truck to not stop like it should. I've almost creamed 3 cars this way. Well actually I almost creamed one, the other 2 would've just been pounded.

One time empty, one time pulling my 33' 5th wheel (and I almost whomped a lady at a traffic light), and one time pulling my enclosed trailer (again at a traffic light). The last 2 instances, I was approaching the red traffic light with traffic and decellerating to the light very gently (which is the only thing that saved those innocents in front of me) and had it timed where I'd be like 15 feet off their bumper once I came to a full stop. But wound up like 5 feet away with some mild panic.

Other than that, it does this cr@p about 75% of the time I am gently breaking, but there is no traffic in front of me to hit. Oh yeah, I DO NOT HAVE ANY LIGHTS coming on the dash. I mean, the test lights come one whin I'm turning the truck on, and every thing works as normal, but I'm not getting the ABS problem light illuminating like everybody else I have read about. Strange.

Should I replace the vaccum sensor? Hyper said it was near the fuse box under the hood on the driver's side? Let me know what you guys think and if anyone's truck is doing similar. Thanks for any help or comment.

- JyRO

JyRO

^^^ Btt ^^^

Joe Diesel

I had the same prob a couple weeks ago. I replaced upper & lower ball joints when I went for a test drive under light braking the ABS kicked in and swerved to the right, the mechanic & I figure some dirt got into the ABS sensor when we put it back together, 3-4days later it went away. I'm going in tonite to get front diff fluid changed & I'm going to pull out the sensor & clean it out just incase

JyRO

Hmmm - where exactly are the sensors? The only possible thing I've done that might have gotten dirt in there is put new brake pads on. I've only had the wheels off 5 or 6 times, one of those being for the pad replacement. I didn't need new rotors. That's the only time I could've got dirt in the sensors ... depending on where the sensors are. Thanks.

JyRO

^^^ Btt ^^^

BigBlue

Your's sounds kinda like mine except it does it very sporadicly and I have ABS and brake lights on and have lost ABS until the next time the unit decides to act up again. I've replaced the driver side front sensor and the rear speed sensor and they did nothing. I guess I need to go and get the codes read.

JyRO

I've been doing searches to try and figure this ABS problem out before I invest money into it. Seems like INFIDEL is the resident expert. I'd like to get his input on this.

The only thing I've found so far with the searches that seems the most similar is an old post from Hyper. He replaced a vacuum sensor near the fuse box on the driver's side. It made all the difference for him.

My front end / brakes are about as virgin as they can be. The only thing that's EVER been done besides about 3 rotations & 1 set of new tires, is that I replaced the front brake pads one time at about 85,000 miles. I didn't replace the rotors, because there was no shimmy indicating rotor warpage. I don't think I or anyone else has managed to get dirt in the sensors or effected them in any way.

The old pads had a large amount of material left, but the squealers (or whatever the small sheet metal backing plates areas are called that start rubbing the rotor) had started making noise. So I replace the pads and that worked great.

The vacuum sensor makes sense to me because it seems to related to something electronic that has failed. Hard to explain. I'm going to PM Infidel to get his input.

- JyRO

BigBlue

When you get a hold of him let me know cause I'm dying to get this thing figured out. Granted, I do love not having ABS but I'm annoyed by the lights and I don't like the idea of them not functioning properly. I also don't like the idea of putting electrical tape over the lights.

REF>Lancer

New to this,Did you check and make sure that the new tires are the same size? A little difference could confuse your abs and make it think one of your corners are sliding....just a thought,as I have had to go back to the tire store to get em to put the right size back on...1 31" and 3 32" tires...

JyRO

Aha, hehehe. I read it wrong at first. I thought you meant ... put all 4 wrong sizes on. But, no, I made sure all 4 were load range E and the correct size. I saw some others in their pile of new tires that were the same size (or very close) but were load range C. I had to make sure I didn't get one of those. Besides, it was doing this before the tire change.

- JyRO

infidel

Your 24 doesn't have vacuum assisted brakes nor a sensor.
Problems like this are when the factory service manual is indispensable. There are pages of tree type diagrams, that tell you step by step the course to take.

gmctd

Do you have RWAL or 4WABS system?

RWAL has the aluminum block with two solenoids on the bottom, under the master cylinder

4WABS has the pump\motor assy on the left fender, with all the steel brake pipes attached.

Either case, the CAB is linked to the PCM and ECM, and requires a scan-tool - have it checked for any fail code(s), and to see if the rear wheel tire diameter ratio is correct for your truck.

dodgetech77

Id pull the diff cover and check to see of the tone ring is damaged. I had one a couple months ago at the shop that the trac lock retainer came apart and smashed a tooth on the tone ring and caused the same condition

Rattlerattle

Are you running stock sized tires?. Soon after putting oversized mud tires on mine the ABS didn't function correctly. Seemed like the ABS was sensing that the tires were about to lock so would start plusing. Stopping distances were increased.

My solution was to pull the ABS fuse and replace with a blown one and remove the ABS error light from the dash. It stops consistantly now and faster. Unloaded in the wet the back end will walk out if you try to panic stop but I can deal with that. Finally got around to doing this after almost loosing my truck going down a steep snow covered road in the bush that with ABS and the break to the firewall the truck just kept rolling down the hill. Not for everyone but work better IMHO.

JyRO

gmctd - I'm going to guess that I have 4WABS. I think so because a) I think I've noticed the pump / motor under the hood on the left fender, and b) I can hear that pump motor running when mines doing this at 5 mph or less.

Now, don't assume I'm a dumba55 because I don't remember about seeing the ABS unit on the fender. My problem is, I see several hundred cars everyday. And see ABS units sitting on the line along with all the cr@p I'm responsible for. Cars have lost their romance for me ... meaning, they're not much of a mystery anymore. I'm not an expert by any means, but I understand how they go together, and details about the parts that go on them. So, it kind of gets old. Kind of like a gynecologist when he comes home and his wife is feeling kind of spunky. He may not be 'in the mood' for any more that day. I like to do the maintenance on my vehicles, but I don't crawl around, notice every detail, or remember any particular thing about it, unless I need to.

There shouldn't be any issues with tire diameter. I'm running the same size tires as original, 265/75-R16. The original tires went about 102k miles, and this ABS crap started at about 95k. So, it did it with the old tires, and it did it with the new tires. The tire shop's work was not a contributor.

My new tires are all the same size and all are Load Range E. I checked that before I drove home due to the shop personell looked like they could care less what tires they actually put on. They did a good job though.

Rattlerattle - I know I could pull the ABS fuse, and its not a bad idea really. But my braking is fine, unless I'm braking very lightly and the speed is 5 mph or less. Not a huge safety issue unless you like waiting until the last 5 feet to complete your stop behind a car in traffic. Then you may not actually stop quick enough. But I leave plenty of room. Pulling the ABS fuse would help. But I like to keep my truck in the kind of shape where when I sell it, nobody has any concerns about it. And I don't have to tell any lies, or avoid telling the perspective buyer of problems.