I have had the ABS pulsing issue for about a year and disabled my ABS system.
Since this past winter my left hub bearing started talking and finally growling to be replaced. I have always had a shop replace them. It was just too costly for me this time. I read here and decided to give it a try. I purchased a Timken Bearing/Hub, I used a loaner socket (went back and bought a new one later). The only issue was cracking the 18MM socket I had, second one I cracked removing caliper bolts on 2 vehicles. I took my time and spent about an hour and a half doing the job +30 min running into town for a new socket and box wrench.
After finishing I enabled my ABS system. Pulsing was still there. I read the DIY section on the service bulletin for ABS. I decided I had nothing but time to loose. I used a Fluke with a max hold function and could barely get 250MV from the sensor. I removed, cleaned, and filed the mating surface down and was able to get 350-400MV, but that was turning as hard and fast as possible by hand. I thought I would check the new hub just for a reference. I got well over 400mv with very little effort. I assumed the sensor needed replaced, and started pricing around.
Due to necessity I buttoned things back up in the wheel and drove, to my surprise the pulsing issue went away. It also did not show up when towing a trailer as it often did before.
Anyways I just wanted to share a little info and a good luck DIY story with others and say thanks to those who contributed here.

 

Glad to hear that you got it all fixed back up & that you were able to do it all yourself!

 

I just replaced the abs sensors, shocks and upper/lower ball joints on our 1995 Blazer. The sensors had a short somewhere and instantly blew a fuse as soon as I replaced them so I decided to change them out while I had everything broken down. Well I replaced the fuse last night when I was done and now have the pulse at stop which is increasing my stopping distance. I checked the hubs and they felt good when I pushed on the tires but what else cause the pulse? With new sensors we know that isn't the problem. With cars this old if we didn't DIY the cost of fixing things would quickly land the old blazer in the salvage yard.

 

If your abs is activating, that means that your ABS control module has detected wheel lockup. This could possibly be due to inadequate output from one or more of the WSS (wheel speed sensor). The WSS should output >250mV-AC voltage when tested with a multimeter while spinning the wheel. If the output is not high enough, the ABS will think a wheel is locked up and pulse the brake pressure to the affected wheel(s).

 

If the sensors are brand new shouldn't they be good or is this a way to find out the bearing hubs are at fault and need replacing? Wish I had just went ahead and replaced them also when I had everything broken down since I know they are the originals and with 140k miles probably getting to the end of their life.

 

Test the output. It is the only way to know for sure.

 

I had a Digital Multi Meter on hand it only took the time to raise the wheel to check. BTW it helps to turn the wheel to give you a bit more room to access the sensor connection. My readings werent perfect after I cleaned the sensor and the mating surface but it was enough to correct the problem, at least for now.

 

Good Job. I'll be doing them next weekend. Maybe you can offer me a a couple of Helpfull hints if you don't mind.

What size is the Center Hub Nut?

Is there enough room to get a socket on the three rear Bolts for the Hub or does the CV boot get in the way?

Did you use a Slide Hammer to get the Hub off the Steering Knucle or did it come out easy enough?