Need some help understanding how to detension the power steering pump belt on my 1990 460 in my motorhome. I must work from above and from back of the motor. Can't see to much of the pulley system from the top. The alternator/smog pump belt is loosened by moving the alternator, but how is the power steering/air conditioning belt tension relaxed? The motor has an idler pulley. Does the idler pulley arm have some way of adapting a wrench to it? Also has anyone replaced this pump? Besides the power steering it provides the hydroboost for the brakes. Any special I should be aware of? Thanks for your help.

 

Don't know the answer, but have seen a few pulley designs that might be on your...

Some idlers are simply spring loaded. On my 96 Chebby, I could unload the tension on the belt just by pulling on the idler with my hands. Other cars you might need to put a socket wrench on the pulley nut and pull ir t in the direction that loosens the spring tension. This is easier to do that tell how, very easy.

Some idlers are tensioned by a adjustment screw and lock screw. These kind of look like an idler that has a sliding groove on the arm with a long screw inside the arm that adjusts how far the pulley moves away from the end. You would loosen the lock screw and then remove tension by adjusting the adjustment screw until the pulley was closer to the bottom of the groove.

The "old fashioned" method was a lock nut on an idler arm with a long groove. Unlock the locknut, get a big screwdriver or something and lever the pulley whichever way you need. THis one is easier with a friend or 3 arms.

There are surely other methods, but these are the ones I have seen in tinkering since the 70s.

Good Luck,

Jim Henderson

 

My 97F250 requires a 15mm wrench on the idler arm nearest where it touches the serpentine belt. put wrench on nut and pull up to release tension. It is 460 engine.