Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > Chevrolet > Blazer
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools
Old 01-07-2005, 01:11 PM   #16
GMMerlin
I know stuff
 
GMMerlin's Avatar
 
Join Date: Jul 2003
Location: somewhere in the dealer
Posts: 2,713
Thanks: 0
Thanked 3 Times in 3 Posts
Re: Re: disconnect 97 Blazer ABS system

Quote:
Originally Posted by tazrock
I thought the same thing as you, that it is an enhancement to the braking and "should do a better job".

That is until the system stopped working and I went back to the good old fashion braking. I can definitely do a better job! I know what is in front of me and how far away it is, as well as what the surface under my tires is. The system will definitely help most people, who have no idea of how to pump the brakes manually in emergency situations.

As I previously posted, try it for a few days, I am sure you will agree.

Maybe the system on other vehicle or the newer Blazers is better? But I am very unimpressed with mine.
I have seen tests with professional drivers vs. ABS stops and the ABS system stopped the vehicle faster..
I don't believe for a minute you can do a better job..you may be more aware and try to avoid situations that ABS may be needed...but I did not come on here to debate...
The fact of the matter is if the system is not working properly, you need to have a professional that is trained on how to diagnose and repair the system look at it and determine what is the culprit...
Until then, you are driving an unsafe vehicle.
__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again?
Got all the certifications
25 years ASE Certified Master Technician
GM WCT
Yea..I work at a DEALERSHIP....got a problem with that?

Want to diagnose cars like the Pros? FOR SALE: OTC Perception 2 channel Labscope (badged as a Matco Reality)
This is my personal labscope that I use to diagnose waveforms, like new, comes with leads and training video
PM Me for details
GMMerlin is offline   Reply With Quote
Old 01-07-2005, 01:48 PM   #17
Fireplug
AF Enthusiast
 
Join Date: Sep 2004
Location: Herminie, Pennsylvania
Posts: 822
Thanks: 0
Thanked 0 Times in 0 Posts
Re: disconnect 97 Blazer ABS system

Thanks for the back up Guys!!
I did not want to start a war over this. I just dont want to see someone get hurt because they are messing with a system on there trucks/cars that they know nothing about.
For all you guys that have worked on GM ABS You remember all the J-Body ABS motor problems.
Fireplug is offline   Reply With Quote
Old 01-24-2005, 09:38 AM   #18
ERASER1852
AF Newbie
 
Join Date: Jan 2005
Location: Chesterfield, Missouri
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via AIM to ERASER1852
Abs

Yea, I agree that the ABS braking system is very unreliable at times. The biggest problem i see is when I encounter a slick surface on one side of the vehicle. The abs kicks in and it takes the car 10 feet to top, versus maybe two or three if the abs had not engaged. This is a very dangerous especially when driving on roads that have just been plowed and the shoulders are still slick. My Rodeo and Infiniti dont have these problems. However; I do agree that in a higher-speed emergency "pedal to the floor" braking situation, the abs helps greatly. In all other situations I would prefer not to have it.
ERASER1852 is offline   Reply With Quote
Old 01-24-2005, 11:02 AM   #19
Allbert
AF Regular
 
Join Date: Dec 2004
Location: Oxford, Mississippi
Posts: 230
Thanks: 0
Thanked 0 Times in 0 Posts
Re: disconnect 97 Blazer ABS system

I actually had a rather serious accident in a '96 S-10 that I believe may have been avoided if the ABS had not come on and increased the stopping distance. There were no system faults indicated at the time... the ABS on that truck was just too stupid BY DESIGN to realize that a small bump under one tire doesn't mean you should drop the brake pressure as though the world has turned to ice. GM acknowledged this on a great number of trucks and SUVs and had a recall to update the software. Still, I would not advise disabling the system; I think the situations where braking performance is improved by ABS are way more common than the opposite. Even though the ABS was a complicating factor, the more significant cause of my accident was stupid driving.
Allbert is offline   Reply With Quote
Old 01-24-2005, 03:16 PM   #20
blazes9395
Newbie mod
 
blazes9395's Avatar
 
Join Date: Dec 2004
Location: Toronto
Posts: 1,477
Thanks: 0
Thanked 2 Times in 2 Posts
ABS or not

Disconnecting it is a bad idea. ABS in itself is a very good safety feature. BUT, to be fair, the ABS system from the early to mid ninties, on GM cars and trucks(including these trucks) was not the best design. The system especially used on these trucks was mediocore at best. Do you remember the safety recall issued on replacing/recalibrating ABS functions on many mid '90s trucks? Do a search on the NHSTA website, recall numbers 99I006000 and 99V193000 I personally think ABS is good, just a bad system on these trucks. No person can pulse the brakes as fast as the ABS system, but a good driver can have good results with a non ABS vehicle. But I guess everyone on here considers themselves a 'good' driver. To each their own. The best system developed that relates to ABS is Electronic Stability Control (ESC), this system, along with ABS, really does work in crash avoidance, but our trucks never had such an option avaliable. All in all, keep the sysem connected, and make sure it works, its apart of the design of the vehicle.
blazes9395 is offline   Reply With Quote
Old 01-24-2005, 03:25 PM   #21
BlazerLT
AF -Advisor
 
BlazerLT's Avatar
 
Join Date: Sep 2003
Location: Sudbury
Posts: 13,565
Thanks: 0
Thanked 1 Time in 1 Post
Re: disconnect 97 Blazer ABS system

WAKE UP GUYS!

ABS is not there to help you stop, it is there to allow you to still turn while braking.

So please stop with the ABS caused my accident crap, and saying you can stop better without it because as good as a driver as you are, you cannot pump the pedal as fast to control your vehicle than a computerized valve system can do.
__________________
1995 Factory Blazer Service Manual for sale, PM if interested.
BlazerLT is offline   Reply With Quote
Old 01-24-2005, 10:44 PM   #22
Allbert
AF Regular
 
Join Date: Dec 2004
Location: Oxford, Mississippi
Posts: 230
Thanks: 0
Thanked 0 Times in 0 Posts
Re: disconnect 97 Blazer ABS system

Agree 100%. As poorly engineered as the S-10 ABS was, I kept it enabled because I knew it was better than me for maintaining control and keeping the tailgate behind me.
Allbert is offline   Reply With Quote
Old 09-16-2017, 01:05 AM   #23
skypilot17
AF Newbie
 
Join Date: Sep 2017
Location: San Jose, California
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Re: disconnect 97 Blazer ABS system

I know that I am chiming in late in this discussion, but I recently had some REALLY wierd problems with my ABS on my 97 Blazer that I bought new and has about 250K miles on it.
The brake pedal was randomly going to the floor, with the ABS light coming on and off, and sometimes the brake light coming on too. The ABS motor was turning on every time I stopped. Scary to drive because the brakes would work really well, and then not at all. I read a lot of forums and the problem seemed to be the ABS unit itself. So I found one on eBay and replaced it. No help. OK, now what?

Maybe a bad replacement unit? But the ABS light was out now, so maybe not. I talked to an ABS control unit rebuilder and explained the symptoms. He thought the problem was hydraulic because the pedal was going to the floor. Well, I had never replaced the calipers or wheel cylinders, so I did that, along with the pads, rotors, and shoes, which were pretty much worn out as well. And the master cylinder too. Good quality NAPA parts.

Now I had really good braking but still had the wierd symptoms with the pedal randomly going to the floor. Air in the system? OK, we flushed and bled the system 3 times. STILL no help. What did I miss??

Did some more reading, including this forum. OH, maybe a bad ABS speed sensor or a broken wire? OK, I pulled the rotors to clean and check the sensors, like some of you guys said. Yeah, good idea. When I pulled the rotors, you will NOT believe what I found.

Yeah, this sounds crazy. Almost could not believe it myself. There are three large bolts that hold the bearing assembly to the brackets on each of the front wheels. These bolts also hold the backing plate with the ABS sensor on it in place. All three bolts on the right front wheel were LOOSE and the backing plate was at an angle instead of being parallel with the wheel. The ABS sensor had been rubbng on the speed ring and was generating all kinds of wierd signals which were driving the ABS controller crazy. Yeah, and me too.

How I missed that when I replaced the caliper and pads on that wheel, I will never know. As soon as I tightened the bolts (and torqued them to spec) all the ABS problems disappeared instantly. No red lights, high pedal, and the brakes really work well now. Well, after replacing almost the entire brake system, they ought to. Have not replaced the sensor and ring on that wheel yet, but parts are on order.

Lesson learned: If your ABS is going nuts, check the sensors before you disconnect or replace the ABS unit. It's just a computer and it only does what the sensors tell it to do. The interesting part is that you can get the sensors at any auto parts store but not the ABS unit. Wny? Because stores stock what they know they can sell. The sensors go bad and they sell. I'm guessing that the ABS units don't sell much, so maybe they don't go bad a lot.

Anyway, thanks to all you guys for pointing me in the right direction.

Hugs.
Skypilot. Yes, I am am pilot - and (surprise) female. I bet you were not expecting that. LOL
skypilot17 is offline   Reply With Quote
Old 09-16-2017, 09:36 AM   #24
shorod
SHO No Mo
 
shorod's Avatar
 
Join Date: Jun 2004
Location: Cedar Rapids, Iowa
Posts: 10,946
Thanks: 99
Thanked 350 Times in 344 Posts
Re: disconnect 97 Blazer ABS system

I had a fairly similar experience on my dad's 1997 S-10 with 4WD. His ABS seemed to only act up when he was in 4WD. Of course, here in Iowa, when you need 4WD, it's often a time when ABS would be most beneficial. On his truck, "act up" meant the ABS seemed to release the brakes when nearly to a stop.

Last Fall we heard a bad bearing in the front so I ordered a new wheel bearing assembly to replace it. The bolts were not loose on his, but the following Winter there were no ABS issues like the past several winters. The bearing was not noticeably loose, even with the wheel installed and off the ground. We only replaced it due to the noise it was making, but apparently it was loose enough to cause a similar issue to your bearing assembly that had loose mounting bolts.

-Rod
shorod is offline   Reply With Quote
Old 09-16-2017, 03:22 PM   #25
skypilot17
AF Newbie
 
Join Date: Sep 2017
Location: San Jose, California
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Re: disconnect 97 Blazer ABS system

Hi Rod,

Yep, a loose bearing will do it. The GM clearance spec between the reluctor (the gearlike toothed ring that is mounted on the axle or rotor) and the sensor itself is .45mm to 1.25 mm. That's about 1/32 to 1/16 inch. Anything outside that will generate wrong electrical pulses that go to the ABS controller. Pulses that are too long or too short or missinig or random give wrong information to the ABS controller and it reacts by turning on at the wrong times. There is a good explanation of this at
http://www.brakeandfrontend.com/wheel-speed-sensors-abs-and-tcs-signal-use/

BTW, in 97 Blazers, the reluctor ring on a 97 Blazer is machined into the wheel bearing assembly. So when you replaced the wheel beari[ng asembly, you also replaced the reluctor ring with a nice shiny, sharp new one.. I'm sure that helped a lot.

As computers go, the ABS controller is pretty tame. It has just enough programming to detect the signals and react. What it -should-do is turn the ABS light on whenever the pusles are wrong. Instead, it generates DTCs that you have to check with a scan tool or a laptop and a plug that hooks the laptop to the OBDII plug. BTW, that is what I use. The plug and softtware cost me only $250. It paid for it self the first time I used it. Any time you get a check engi[ne light, it displays the DTCs and tells you exactly what is wrong. www.autoenginuity.com.

BTW, my Blazer had exactly the same symptoms as your dads. The pump would turn on when I was alomst stopped and would not turn off until I released the brake and then braked again.

The biggest problem with the sensors is that because it they are magnetic, they attract metal shavings from metallic brake pads or shoes. When enough shavings are piled up around the magnet, the sensor no longer generates a big enough pulse and the ABS does not work right. Simple solution: Clean the sensors on all the wheels every few months. Wash all the dirt and metal particles off both the sensor and the reluctor (speed ring) and blow dry with compressed air. Depending on the installation, you might have to pull the rotor off to get at the speed sensor.

BTW, some guys might wonder how come a woman knows all this stuff. Well, I am a mechanical engineer and a long time ago, I used to work for GM. :-)

Cheers,
Diane (skypilot)

Last edited by skypilot17; 09-16-2017 at 06:14 PM.
skypilot17 is offline   Reply With Quote
Old 11-27-2023, 04:37 PM   #26
g1smith
AF Newbie
 
g1smith's Avatar
 
Join Date: Mar 2005
Location: murray, Utah
Posts: 85
Thanks: 0
Thanked 0 Times in 0 Posts
Re: disconnect 97 Blazer ABS system

Checkout NTSB investigation EA94-038 noting 10,000 complaints, 2000 accidents, 600 injuries. Chevrolet Safety campaign 99I006000 addressing a PCM coding change and replacing the Kelsey Hayes ABS actuator unit.

Chevrolet at 800-222-1020 declines to honor it 20 years later.

My 1996 Chev Blazer exhibited the symptom on slushy roads last winter, just about totaled a Tesla. Then a guy I work with stated that his Suburban of the same era would do the same thing, extended stopping distance. Followed my neighbor down a hill in his brand new 2013 Chev pickup years ago, and watched it roll right through an intersection on slushy roads, my Explorer stopped without issue. Back in the 1980's had a Chev Skylark, back then their idea of antilock brakes was a shock absorber mounted on the back of the break pedal to "dampen' the application of the break pedal, yup, rear ended a car because of that. Tested stopping distances between that car and a Chev Malibu before antilock stuff was around, the Malibu stopped way shorter. What's up with these GM engineers, deals with the collision shops?

Then 1996 Chevrolet Blazer Recall NHTSA 99I006000. Although not a safety recall

VEHICLE DESCRIPTION: CERTAIN 4-WHEEL DRIVE PICKUP TRUCKS AND SPORT UTILITY VEHICLES EQUIPPED WITH ABS (ANTILOCK BRAKING SYSTEM) MANUFACTURED FROM SEPTEMBER 1989 THROUGH AUGUST 1996. UNDER CERTAIN DRIVING CONDITIONS THE SWITCH WHICH SIGNALS THE ABS SYSTEM WHETHER THE VEHICLE IS IN 2-WHEEL OR 4-WHEEL DRIVE CAN MALFUNCTION CAUSING INCREASED STOPPING DISTANCES DURING ABS STOPS WHILE IN THE TWO-WHEEL DRIVE MODE.

Remedy
DEALERS WILL REPLACE OR REPAIR THE 4-WHEEL/2-WHEEL DRIVE SWITCH.
g1smith is offline   Reply With Quote
 
Reply

POST REPLY TO THIS THREAD

Go Back   Automotive Forums .com Car Chat > Chevrolet > Blazer

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 09:55 AM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts