Manager Forum

I have a 2005 k1500 with rear drum over 8600 gvw. Have very good brake pedal pressure when stopping at any speed over 10mph. when at low stopping speed and light pressure on pedal it will do one of two things. either the abs kicks in and pedal will pulse a little or abs will not engage and pedal will drop about an inch or two. abs sensors are working

With a scanner showing the sensor speed watch it when applying brakes approaching 5mph. It is extremely common for a bad speed sensor to trigger the system. There is probably one that will drop to 2 or 3 mph when the other front is still at 5. That's all it takes to trigger. In my shop if the vehicle has high mileage I recommend two sensors and I don't use the off shore crap, way to many issues. I'm not trying to preach just hope other learn from my trials. Being in the nor east when a GM comes in with this issue I look for all sorts of other brake issues as well along with bearing bolt issues. I stock them because of so many rotted heads or frozen snapping ones.

As Steve says, low speed unwanted ABS activation is common on GM trucks. Use a scanner to determine which sensor is dropping out. Usually what happens on these is rust builds up under the mounting for one or more of the front sensors. That increases the air gap between the sensor and the tone ring, which in turn makes the sensor drop out at low speed. I have been very successful at removing the front sensors, cleaning the mounting and re-assembling without new parts. Of course, new is always best and may actually be needed also. Just remember to clean those mountings.

I agree with Steve and Ric......except......here in the salt/snow capital of the midwest we seldom can save the speed sensor. They are generally broken before we can get them out.

Thanks for input. i did scan it both front front sensors drop for 6 mph to 3 mph and same time. at complete stop both front sensor still show 3 mph

It's that missing data from 6 to 3 that is your issue. Many of the GM's don't read pids below 3 mph. If they're both dropping at 6mph, pull them off and clean the mountings and retry, unless you want to sell 2 sensors.

How did it work out?