Rear ABS freeing brakes on dry road
 

If I apply consistent brake pedal pressure, everything seems fine - roll to a stop with all four wheels braking. If I push a tad harder during the stop, both rear brakes release. There is no skidding and this is on dry paved roads. Happens every time. Never happens with a trailer attached. I know I'm light in the rear but my 99 1500 never seemed to suffer from this. Brakes check out fine as well as ABS controller. Overly sensitive to bumps with the stiffer suspension of the 2500? I don't know. Anyone else experiencing similar?

Thanks,
Ajg

I know exactly of what ye speaketh. Go over some stutter bumps while braking for a stop sign and- Woa big truck! Work brakes, WORK!!!
They say the front brakes do most of the stopping???? They don't seem to be very effective when the rear ABS kicks in!
A fix would be great! Mike

Guys I was just about to start a thread about a similiar experience. For years, I have burnt up front rotors,calipers & pads & the back ones look barely used. I can tighten the back ones up until they burn going down the road. They just don't seem to work. I had a friend of mine that many of you Big HP Junkies know. He is from McDonough,GA near ATL. He said he took out the plunger in the ABS sensor way back one time on his race truck to get more pressure to the back wheels.This is the one that has the little rubber or plastic cap on it. I am about to try this, unless someone has a better suggestion. I have the big Chevrolet wheel cylinders( Napa # 37337). This doesn't seem to help. I have played with the proportioning valve. No help there. I was thinking of swapping the front & rear brake lines coming out of the Master cylinder. I wonder what that would do? I also thought about trying the later model 4 wheel disc brake Master cylinder, since it is bigger. It doesn't have just a bigger Tank, it has a bigger bore. I have replaced the lines & EVERYTHING several times, but nothing helps. I put a rearend with disc brakes on it, & still couldn't get enough pressure to the back to make them work right. I bought this truck new,in 1999, & it has always been like this.
I will be tinkering with this on Tuesday. I at least have to pull my front pads off & scuff them up, & put them back on, to get the glaze off of them. any ideas, will be greatly appreciated. I may even offer up a Reward for the best idea. Thanks.

I think these RWAL systems were made to keep the rear of empty trucks from swinging around in a hard stop. Washboard surfaces will make the front skip around like mad. Id like to get better suspension myself.
You could do a couple things to disable the ABS or make the rear braking force stronger. Chevy one-ton wheel cyls are a good add-on but they seem to make the rear brakes skid more often in normal stops. Id do these along with a proportioning valve so you can adjust the braking force. unplugging the sender on the rear differential might work (maybe put another sensor or a resistor on it to keep from getting codes).
I like the proportioning valve idea since you can adjust for empty and full loads.

I had the same problem with the ABS on my Grand Cherokee. Coming to a stop everyting would be fine and fine just at the LAST 3-4 feet the ABS would kick in and I'd end up rolling an extra foot or two. Pretty scary when pulling up to a pedestrian walk! :o

I hooked up the scanner (Snap on) from work and by watching the sensors I could see that one sensor(Rear Right) was not reading speed below 5mph, the rest would read right down to 2mph. So when coming to a stop the RR wheel would read down to 5mph and then drop to 0. Computer would think that RR wheel was locked up and would activate ABS.

The fix was simply to cleanup the sensor and push it fully into its seat. I believe it had backed out a bit and was too far away from the tone wheel to get a proper read at low speeds. Computer never threw a code as it simply just thought that the RR wheel was locking up.

Hopw this helps.

Well, I have a new speedo sensor, if that is the one being referred to. I will check the ones next to the wheels. I have already tried adjusting the proportioning valve with no luck.I may definetly get the computer check done, & see if these diesels show the brake performance like the Cherokee did. Thanks.

I can't remember does a '99 have four wheel ABS or just the rear? Is there one sensor per wheel or just one in the diff that reads to ring gear?

I'e been under my '01 for almost two days straight and I think it just has one sensor in the diff and then one sensor per wheel on the front.

Maybe just try cleaning them, look for breaks in the wires and make sure they are seated all the in the bore. On some styles you actually push it lightly against the tone ring and then when the wheel starts turing it actually pushes it back slightly.

Clay the 99 just has rear ABS, & I guess just the speedo sensor in the differential. Come on guys, I know someone out there has to have some ideas on how to attack these brake problems.

Boy, now that makes sense. GM has been dogged by that problem (but both front and rear) for over 10 years. My 95, 96 and 02 Suburbans all had enormous ABS brake problems with the 02 being recalled for exactly that problem - brake dust/dirt covering the sensor causing the ABS system to not know if the wheel is moving. Also occurred at lower speeds (10mph) and the ABS system would release both rear wheels. I'm pretty sure there is only one sensor for the rear wheels on the Ram, at least that was true with the GMs. So effectively, if you lose traction on the one with the sensor, you lose it on both rear wheels. DOOOH!

Bought my 99 new. Both 2 wheel and 4 wheel ABS were options. Mine had 2 wheel (rear wheel only). Never had a problem with the 99 but the 1500 suspension was mush compared to the 2500.

is the abs kicking in and making the whinning noise? of so it could just be a build up of metal shavings on the abs magnet sensor in the wheel housing.

didn't i read on here somewhere about pulling the glove box and unplugging the rwal?

Mine just aren't working. I did mash the park brake & that SOB, like to have rolled me, on a dirt road. So, I know I have good brakes, just not getting the juice to them. Anyone with ideas, please help. Thanks

The parking brake will lock my rear brakes up or make it very hard to move if forgotten so the braking power is there.

Now Speedway and Summit as well as several others sell an adjustable proportioning valve that works on streetrods that may do the job here. I have used them on the street rods both with rear disc and rear drums. They run about $35 up depending on where you get them. There also are 2# and 10# residual valves that may help. Use the 10# with rear drum brakes. These will keep a small amount of pressure in the rear lines which is supposed to keep the shoes very close to the drums. Then when the brakes are applied there is not so much volume to move before the brakes apply. These things really do the job on our hotrods but our brake systems are less complicated than the trucks. Why??? go figure.

I don't have my own shop anymore or I'd be inclined to try these. If nothing else just run new brake lines parallel to the existing ones so you don't have to alter the originals. The worst that could happen would be to use up some brake fluid and have to bleed the lines a couple times. Someone could do us all a big favor here.

[coffee]

I got to check to see if I am getting enough pressure to the proportioning valve. If I have enough pressure there, I will make my proportioning valve adjustable, by cutting & threading the rod. no need to buy one. I am surprised we haven't gotten more info on this from guys who have tried other things to get their back brakes to work. We all know how sorry the 98-2000 rear drum brakes were. Maybe people just thnk they are working, and haven't looked at their front rotors in a long time. Ruined front rotors & good looking brake drums equal, NO Rear Brakes.