1996 1 Ton Chevy 4x4 ABS problem... interesting one!

[Chad Flaugher]

Okay, so I performed the test as lined out in your link, and it did exactly what it said it should do. I have to say though, I learned something today, and that's a good thing! Better understanding a system like this will help diagnose the problem, and others to come! Vacuum boost is what I generally deal with... Again, in smaller trucks. Thanks, for pointing that out. I won't rule it out completely.

 

[wrench 3]

I forgot to mention earlier that with a messed up ABS operation it most likely won't set a code. Because if it knows something has a problem it will shut the system down and revert to standard brakes. It's one of those "if you're crazy do you know that you're crazy" deals.

 

[Chad Flaugher]

On the rare occasion that it does throw an ABS light, it's only briefly. This problem is ridiculous. So even if I did decide it's worth taking into a shop, ya know dern tootn' well it would work perfectly for the tech! :facepalm:

 

[glenn property of pam]

most ecm/tcm have a memory that can store historical codes. Normally its only the last 5 faults. The trouble is that some code reader can not access that option which is why the dealer has the better scanner. I was wondering if the power steering has a pressure relieve that operates when the steering is turn more than full lock. I haven't looked at your truck type but Im presuming it has a power ram rather than the power steering being built into the steering box. Im also wondering if hard right is when the cylinder is at max travel which is when the oil in the reserve would be lowest. If abs kicked in which would reduce the pressure to the wheel that it thinks is locked when it adds the pressure back its possible that theres no pressurized oil available.

 

[Chad Flaugher]

Master cylinder power steering

 

[Chad Flaugher]

Not sure if that helps... I assume the accumulator is the brass or gold colored cylinder just below the reservoir? I guess I was a bit low on power steering fluid...:chargrined:Topped it off, and we'll see! I've never connected the two until now.

 

[dwco5051]

Not sure if that helps... I assume the accumulator is the brass or gold colored cylinder just below the reservoir? I guess I was a bit low on power steering fluid...:chargrined:Topped it off, and we'll see! I've never connected the two until now.

Yes, that is it. The low fluid level may have been your problem. Pumping foam does not make good fluid mechanics. If you ever replace the booster be sure to read the instructions carefully. They must be bled by cranking the engine with the coil wire disconnected if yours is a gas job. Due to the many problems with GM truck brakes there are a lot of good youtube videos to make the job easier.

I replaced the booster, master cylinder and a bunch of rusted brakes lines on mine and then found out I couldn't over ride the ABS codes with my scanner to get the lines all bled. Had to call a mechanic friend to come over to my cold shop with his setup to get it finally right. Its a good thing he needs some landscaping done this spring and I told him I will haul my skidsteer down when the weather breaks. I can't imagine what a good mechanic charges for house call to a garage with no heat when the outside temperature that night was about 10 degrees.

 

[Chad Flaugher]

I own a landscape maintenance business too! LOL Now to find a mechanic in need... 'cause that didn't fix the problem.:doh: This all started about 6 months ago. I pulled the main ABS fuse last fall and all was good. I swapped out all the parts before mentioned, because it needed to be done anyhow. Put the fuse back in when the snow started flyn' and NOPE. Same as before. I scanned codes just to see, but nothing was stored. I think I'll just be pulln' that fuse again.

 

[glenn property of pam]

in a straight line on a gravel road if you slam on the brakes what does the truck do?

 

[bruceb58]

I scanned codes just to see, but nothing was stored. I think I'll just be pulln' that fuse again.

Does the scanner that you have pull chassis codes? Most of the plain jane ones only do powertrain codes.

I own the autoenginuity scanner. Not cheap at $250 plus enhanced packages. Here is the GM one which is probably needed for ABS. Add $200 for this enhancement:
https://www.autoenginuity.com/produc...mily-ei02.html
Well worth the money though if you are doing diagnostics for things like you are doing. Since you likely don't have this type of scanner, you need to find a mechanic that does.

Have you had any brake work done that required brake bleeding being done? If so, you really need the type scanner that puts the ABS in bleed mode and opens up all fluid channels in the ABS so that all of the air can be bled properly. I know this is needed for 2000 and newer trucks. Not positive regarding older ones like you have.

Personally, I would get the ABS working properly. Is a safety issue.

Does your truck have anti lock on the back as well as the front brakes? Some of the GM trucks in the 90s only had ABS on the front.

 

[bassman284]

I own a landscape maintenance business too! LOL Now to find a mechanic in need... 'cause that didn't fix the problem.:doh: This all started about 6 months ago. I pulled the main ABS fuse last fall and all was good. I swapped out all the parts before mentioned, because it needed to be done anyhow. Put the fuse back in when the snow started flyn' and NOPE. Same as before. I scanned codes just to see, but nothing was stored. I think I'll just be pulln' that fuse again.

Ok, I'm just trying to catch up here. You say you pulled the ABS fuse and all was well? Did you try driving it in the snow WITHOUT ABS? You might like it.

OK, before everybody starts throwing rocks at me, I know what I'm suggesting is"unsafe", but hear me out. About 6 years ago, the ABS light came on in my 97 Grand Cherokee. This happened in October or November somewhere and I decided to drive it through the winter to see what happened and It. Was. Great. Real brakes that I could use the way I'd learned as a youngster. I decided how the brakes should work, not some stupid computer. I've always hated ABS. I guess it's good for people who don't know how to drive but don't even try to tell me you can stop better with it than without. I've done it both ways and I know different.

 

[Chad Flaugher]

Glenn: The ABS works perfectly. The brakes are amazingly strong, the ABS pulses and keeps the tires spinning slightly just as it was designed.

Bruce: Nope, I used a cheapy scanner. There is a mechanic around the corner from me, I may see if he has one. He works out of his garage despite being a ASE certified GM tech. It's been a few weeks since I've had the light come on. The problem started before any service work on the braking system was done. The problem was unchanged after all the components were replaced. Yes, I replaced the calipers. In doing so, I pre-loaded them, and bled the brakes via wife and "up....down..up...down...." method. (no pun intended). That might be suspect had it not already been a problem before. I would think air in the system would create a more consistent problem? As far as I can tell, the ABS system is a front only system.

bassman: Well, I'm certainly not going to cast stones at you! I started out driving vehicles with 4 wheel DRUM brakes! (69' Ford Bronco '74 Maverick and various farm trucks) I absolutely hated ABS when it came out, and I'm still not a fan. If ABS was a perfect system, you'd see it in race cars. I absolutely feel as though I can out stop an ABS system on ice. My wife needs ABS, not me! LOL However, I am anal mechanically speaking, and having a problem with ANY system bugs the hell out of me! Pulling the fuse caused no problems, lights or anything. If I can't get figured out here soon, I will pull the fuse for the summer, and take another stab at it next winter.

ALL INVOLVED: I have noticed a new consistency once the truck has warmed up. If I shut it off for a few minutes, and start it back up, I can make it fail if I make a slow hard right turn within the first 5 or 10 minutes of running. Once its been running a while, seems to be less frequent or maybe non existent. Even stranger?