The Stovebolt Site Forums The Parking Lot '60-'66 Trucks ABS Brakes

I looked and could not find any reference to this topic, I have a 66 gmc that I am going to use as a daily driver, one of the donor vehicles is a 1991 suburban with abs brakes. Has anyone done this conversion ? I thought I would use the complete front end, rear end , master cyclinder, and abs computer. I know this is a little high tech but thought the benefits might out weigh the drawbacks. Am I on the right track ? or should I just go on and do it up with std power disc brakes? Kieth

Hy Kieth, that would be a very ambitious project indeed. You would have to use all the parts designed for use in that system, with no substitutions, or omisions. If I were going to undertake such a conversion, I would use the newest system available, that way hopefully you will avoid any of the problems of the early systems, good luck.

I agree with 3B about using every piece of the system, and it might even be an issue putting the suburban system in a pickup because the weight and balance may be off. Just one person’s opinion, but I would have no interest in a project like this because of my dreadful experience with early GM ABS brakes.

In 1994 I bought a new S10 with 4 wheel ABS, which had the scariest brakes I’ve ever experienced. At the time we lived in North Idaho in a snow and ice belt, and winter driving was already rather dangerous. Year round for most of 9 years I drove my 1960 GMC 36 miles each way to work and back, with stock rear drums and 1975 disc brakes up front. I never had a braking problem driving on snow or ice, and could easily feather the pedal and stop at will from just about any safe speed.

From our house to the highway was a half mile private road, crossing train tracks to arrive at the highway. The road turned to packed snow and ice all winter long. On the first trip to the highway in the S10 (on ice) I eased down on the brake pedal to stop. Instead of stopping like normal, the pedal went to the floor and the truck rolled right over both sets of tracks, and I driving less than 10 miles an hour. I was very lucky the tracks were empty at the time.

I couldn’t get rid of it fast enough, and this was also a turning point in my life. After owning mostly GM cars and trucks my entire life, the brakes in that truck convinced me I would never own another one. I was appalled GM actually released something so dangerously ineffective to the public.

Our daily drivers are now a Toyota Corolla and a Honda CRV with ABS. When braking on ice, the Honda demonstrates none of the bad GM braking habits. When the ABS kicks in, the pedal “vibrates” a bit and the car stops like it’s chained to the road. Other people may swear by GM ABS, but I wouldn’t have that system if it was engineered for my truck and installed for free.

In order for the ABS to work using the parts from the '91, you will need to use the transmission as well. On the early GM truck abs, the abs only works on the rear wheels, and the sensor is in the transmission, rather than the axle. You don't say if the donor vehicle is 2wd or 4x4, but the abs is only operable in 2wd mode if it is 4x4.
My personal opinion, I wouldn't bother with it. 90% of the time, the abs will be inactive. Also, most people are under the misconception that abs will make a vehicle stop in a shorter distance, it does not. In fact, comparing abs vs same system without abs, the non-abs will stop in a shorter distance. The abs equipped brake system is more about control, as it allows the wheel to roll rather than lock up, potentially causing a slide or skidding situation.
Markeb, I have experienced what you're talking about, especially on the 4 wheel GM abs systems. Seems that if they get a bad signal from the sensors, usually a front sensor, they rear it as a "lockup" situation, and release that brake. The newer ones are better, but they even still do it to some degree, but without the total loss of braking that you experienced. It's one of the bigger complaints you'll see when the magazines test GM vehicles, though they stop just fine.

The donor is a 2wd and after removing everything I came to the same conclusion as y'all, not worth the trouble. It was just fun to ask. I remember one of my friends got his first abs gm truck, he lived on a gravel road, missed his driveway the first 3 tries. On motorcycles they put a on off switch on the abs for varying conditions. Kieth