Replacing a Serpentine Belt with a Jacking Screw

Video Transcript

"Hi! My name is Nate McCullough on behalf of expert village.com. In this clip we are going to talk about the proper way to install your accessory drive belt with a jacking screw style tensioner. When installing your new serpentine belt or drive belt for that matter, what you are going to want to do is loop the belt around all its pulleys. We have it looped on the bottom two pulleys all ready. I’m going to show you the proper way and the seat you are looking for on a pulley, right up here on the top. We are going to slip the belt right on top. If anyone has ever started a bicycle chain, it is pretty much the same procedure and go ahead and roll it over, just like so. You can see how the pulley sits in the middle and it is nice and flat which indicates that our ribs are aligned properly. Once you have the belt on, it is okay to go ahead and run down your jacking screw. I don’t recommend using your tools for this procedure. It’s best to do this kind of stuff by hand. You only get one shot with an air tool. The tension you are looking for on your serpentine belt or V-belt for that matter is measured in deflection. On this particular vehicle, it happens to be one-half to quarter inch from parallel. How you measure that is you would take a ruler between two pulleys. You would then tug on the belt. If it moves a half to quarter inch pulling as hard as you can, that is going to be within specification. The rule of thumb for all vehicles is to be able to rotate the belt, turn it as hard as you can one-half inch; as you can see on or 90 degrees. As you can see as I yank on this belt, which is all the farther I can turn it. That indicates that the belt is properly tensioned and you are okay to go ahead and run down your mounting bolts. You are going to want to pay particular attention to the direction the bolt is threaded. It is going to either be left land or right hand thread. On this particular vehicle, the upper mounting bolt is a right hand thread. As you can see I am turning it clockwise to tighten it. The bottom mounting bolt on this particular vehicle is left hand thread. It rotates clockwise to loosen it. This one is actually backwards. It’s going to lefty, tighty righty loosy. Go ahead and put a couple of turns on our bottom mounting bolt here. Okay. That is the proper way to install and adjust our serpentine belt with a jacking screw style tensioner. "