matt66147

Hello everyone. I'm not a member, but found this thread when I was having similar issues with my 2017 sierra denali. My DS running board would try to extend when I opened the door, but would immediately fold back under the truck. Other times it would extend out, but slowly. I could pull it out manually with my foot if I caught it in time while trying to enter the truck. I began tearing into this problem by loosening the 2 allen head bolts that clamp the arms to the step motor and the guide bar at the rear. Next I took out the two 10mm bolts on the lower bracket on the steps which hold the bottom mount for the arms. The 1" nut for the arms under the step was next. Lots of penetrating oil on all 4 mounting points. I found my problem pretty quickly when i tried to remove the rear arm from the step. It would not budge. Tapping with a hammer, prying with a pry bar, and doing both at the same time didn't' do a damn thing. After about an hour of repeated spraying with penetrator and hammering/prying, i was able to move the rear arm enough that I could fit a two-jaw puller onto the end of the arm. The arm finally came off! The red bushing inside was in decent shape, but it was full of crap. I cleaning it thoroughly and applied red grease. I cleaned up the mounting stud on the step with emory cloth until it was shiny again, and greased that as well. After re-assembly, the step works perfectly. I apologize for the lack of pictures. I was covered in wd40, Liquid wrench, road grime, and grease, so I wasn't going to touch my phone to take pics! It took me about 3 hours, and I had my truck on a lift. It isn't a terribly technical problem, but it is a pain in the butt.