2001 Silverado wheel speed sensor

My silverado's anti-locks activate at low speeds as reported in several other postings. I measured the voltage generated by both front wheel sensors and came up with approximately 150 mVac on each (0.15 VAC). One posting indicated the voltage when you spin the wheel should be around 300 mV, so I am leaning toward both sensors being weak. The sensors have a plastic housing and are mounted in the hubs and held in place with an allen screw. When I remove the allen screw, should the sensors pull straight out? Is there anyone who sells the sensors other than the GM dealer - that is the only place I can find them and I think $108 each is a little excessive for what they are. Thanks!

try pulling and cleaning surfaces first before you replace them...JJ

Thanks for the reply - should the sensors pull straight out? I tried to remove one after taking out the allen screw - it twisted a little, but didn't want to break it by forcing it out.