Yesterday I pulled the smog pump off as well as the idler pulley/tensioner to try and troubleshoot a squealing noise. Sprayed the pump with penetrating oil and put everything back together. This morning the outside edge of my belt was frayed pretty bad after a 15 minute drive. Got a new belt and now within 2 seconds of starting the truck the belt jumps off of the crankshaft pulley by one rib. I didn't touch that pulley and I really don't see how I could have put something in backwards. Any ideas on this? The truck is a 1992 f150 302.

Thanks,
Matt

 

Remove the belt and spin each pulley by hand to check for noise, binding, looseness, or roughness.

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The smog pump should spin smoothly with some resistance. Read this caption:

 

Update: found the problem. The power steering pulley was almost a 1/4" out from where it should be. Pressed it back some and belt is functioning as it should. Steve83, thank you for your advice.

Matt

 

How did you press it back? If it worked its way out 1/4", there are other problems.

 

I bought the removal/install tool about a month ago when I changed the ps pump. It is just odd that everything seemed to happen when I was working on the smog pump, which is why I didn't guess it to be related to the ps pump. All is good now so I'll continue to watch it closely over the next week.

The truck does not get driven daily so maybe it just took that long for the belt to start tearing up.