Three problems related to brake antilock wheel speed sensor have been reported for the 1998 GMC Sierra. The most recently reported issues are listed below.
My wife and I own a 1998 GMC k1500 4x4 pickup truck. This vehicles suffers from the stopping problem due to fouling of the speed sensors in the wheel hubs that was the subject of a recall for similar 1999-2002 vehicles. The NHTSA has encouraged gm/GMC to recall similar 1999-2002 vehicles. The 1998 vehicles with the same brake system design was not included in the recall - you guys missed the boat. Why didn't you suggest that gm/GMC recall all vehicles regardless of year with the same problem?.
Anti- lock brakes activate at low speeds when not needed making stopping difficult. This occurs due to problems with the wheel hub speed sensors. The 1999 and up models have been recalled for this problem but the 1998 have not. I have had this problem repaired twice.
The anti-lock brake system will activate prematurely on dry pavement when slowing down from 10 mph-zero. It will do this ninety-nine out of hundreds times. Had to increase the stopping distance tremendously in order to keep it from hitting another vehicle. Noticed this on April 15, 2003. The abs light does came on the dashboard. Took vehicle to the dealer, the service technician determined that it was the front wheel speed sensor. This problem arose several times with the dealers. The brake pedal was soft and it had something to do with abs system.