Question for the brake experts out there

[BuickTurboSix]

My tow vehicle is causing problems and I am hoping someone on the Brake forum can help out. It is a 97 Suburban with ABS. The ABS is engaging on dry pavement. Is this a common problem on these rigs and the similar Trucks?

First, is there a way to disable the ABS without harming anything?? If so, what do I do?

2nd, How can I determine what sensor is failing causing the false signal?

3rd, How hard is it to replace the front hubs with the sensors in them? Any tricks I should know? Is there any service that can be performed on them - cleaning etc?

Thanks for the help!!

 

[kh440]

Is your suburban a 1500 or 2500 series? The 2500 models with the7.4 have had some trouble with the modulators going nuts, but even on them it's not all that common. In order you asked:

#1 you can try pulling the abs fuse, I wouldn't try to disable the system, but I tend to be overly cautious on brake systems

#2 without the correct scan tool and software you have a 1 in 4 chance at it. most independent shops have the equipment.

#3 If yours is 4wd the hub/sensor bolts onto the steering knuckle (2wd it is made onto the splash shield) If you have ever done a GM FWD hub you can do this.

Bottom line: have someone qualified to at least diagnose the problem (can be more expensive in the long run to just throw parts at it....lesson learned the hard way)

 

[BuickTurboSix]

Hi, Thanks for the tag back. It is a K1500 4x4. I tried the qualified professional and struck out. They couldn't determine with any certainty what the cause was. Said to start throwing parts - That was the Chevy Dealer that sold it new to me, so!!!

Reason for disabling is that it would be safer without the ABS now that winter is over than with it going off all the time. You feel like you are going to hit the car in front of you all the time as it takes longer to stop on dry pavement on normal slow stops with it activating all the time.

Will the hub slide right off, or will I experience some difficultly? Will I need a puller or will I need to heat it up?

Can have excessive rust scale on it and can it be cleaned off and made to work again?? Or is it pretty much junk at this point?

Thanks again for the help.

Tom

 

[mayosmechanic]

Wow that's nuts that a GM dealer can't give you any more than that.Makes us Independents feel better.Anyway,you need to hook a scan tool to it and monitor your wheel speeds.You will probably find the rear sensor out of wack.Does your pump run all the time?It's located under the driver side rocker panel.If so find a good used one at a salvage as new they are about 1300 bucks.HTH.

 

[BuickTurboSix]

Pump?? What Pump - Oh no!! I didn't know there was anything down there associated with the ABS. I knew about the rear sensor. That is in the Transfer case? Are they easy to replace? I don't think it is the pump as it only does it for the last 20 feet of stopping.

 

[mayosmechanic]

The pump is just inside the frame rail under the drivers rocker.If it runs all the time it's toast.I really suggest finding someone in your area who will get in the data stream and check it out.ABS parts are just too high to throw at it.I have replaced many ABS Modules(pump) for running continually,but you need to diagnose it first.When do you problems and which corner is locking?

 

[BuickTurboSix]

More info

It fails intermittently in the last 20 feet of stopping. The dealer says that it "Sorta" looks like the left front or rear sensor kicking off the system. They say it is more likely the left front due to being exposed to the elements and rust? But no guarantee that this is the failing sensor. They had a graph of driving the car and applying the brakes and it didn't show anything conclusive. They said that this vintage of ABS was difficult to Trouble-shoot down to a specific component when it wasn't fully failing 100% of the time.

 

[POWERBRAKEBOB]

UPGRADED BRAKES

HI! BOB HERE. WE HAVE HAD A LOT OF EXPERIENCE WITH THOSE VEHICLES, MANY PULL A TRAILER WITH THEM. THE NUMBER ONE PROBLEM WITH SUBS IS THAT THEY HAVE PICKUP BRAKES AND PROPORTIONING TO THE SYSTEM. THE SUB CARRIES THE WEIGHT OF FOUR SMALL BLOCKS IN THE BACK. THE REAR BRAKE PRESSURE IS SO LOW, THAT THE FRONT PADS AND ROTORS BURN AND OVER HEAT. WHEN THE PADS BURN, THEY ACT GRABBY, AND DO WIERD THINGS AS THEY WARM UP. EVERYONE COMPLAINS ABOUT WARPING ROTORS. IT ALWAYS GOES BACK TO THE WEAK REAR BRAKES. THE PEDAL ALWAYS SEEMS MUSHY, ALSO. WE HAVE BEEN INSTALLING THE 2500 CALIPERS AND PADS FOR THE FRONT. THEY ARE 80 MM AND THICKER PADS, WITH CROSS DRILLED ROTORS. WE HAVE A DIFFERENT WHEEL CYL AND SHOE COMBO FOR THE REAR TO RAISE THE BRAKE POWER AND HELP BALANCE THE FRONT TO REAR BIAS. YOU NOTICE THE BLACK DUST ON THE WHEELS? TOO MUCH FRONT BRAKE. THE MUSHY PEDAL IS CAUSED BY BOTH STANDING ON THE PEDAL AND EXPANDING THE CALIPER CASTINGS, AND THE 2 STAGE MASTER USED ON THOSE. ALONG WITH THE 80MM CALIPERS AND PADS, WE CONVERT THOSE TO HYDROBOOST AND A STRAIGHT BORE 1.250" MASTER FOR MORE PRESSURE CREATED BY THE HYDROBOOST WHICH HAS THE POWER TO PUSH THE LARGER MASTER CYL. WHEN INSTALLED THE WIFE CAN ROAD RACE IT. WE SHIPPED A BIG BRAKE CONVERSION TO THE SECRET SERVICE IN KUWAIT FOR A SUB. IT WAS LOADED WITH 3000LBS OF ARMOR PLATING AND A BUILT 502. THEY WERE VERY PLEASED WITH THE RESULTS. WE CAN SHIP IT TO YOU AS A KIT. THANKS, BOB

 

[BuickTurboSix]

Brake kit

What is the cost of the kit?? Front only (if available) and the full kit? - Thanks - Tom

 

[BuickTurboSix]

** Update One

I did pull the fuse just to see what happens. It is Fuse 18 in our 1997 Suburban. It turns off the ABS and the ABS light on the dash comes on. So the brakes operate like a regular NON-ABS brake system. Which is really a better default with this problem than the falsing ABS on dry pavement. So, I thought I would let everyone know what can be done until you have time to address the problem.

The one negative of doing this (removing the fuse) is that the Cruise Control is wired to the same fuse, so if you pull it, you also loose your Cruise control. That kinda sucks as I use it all the time. I am going to see if there is a plug that can be pulled going to the ABS module under the hood instead to retain the cruise. I will post my findings once I check it out.