The reason (I think anyway) that the power steering pump belt slips/squeals more frequently than the other belts is because it usually doesn't get properly tightened in the first place. And the reason for that is because - for one man to do it alone is a pain in the butt.
First, consider the alternator; it is located in an accessible/clean spot -
and it uses the simplest method to adjust/set belt tension (pivot point and and a mounting bracket with a single elongated bolt hole).
On the other hand, the design of the components used to mount the power steering pump make adjustment of it's drive belt ... cumbersome to say the least.
It does have the standard pivot point:
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But instead of just a single elongated bolt hole, the bracketing for the PSP has two slotted adjustment points - and both the associated clamping bolts must be moved through the slot simultaneously.
One of these is located in an easily accessible spot - the upper LH corner - and just like the alternator, the bolt is moved through the slot to adjust tension :
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The second adjusting point for the PSP is there to provide more stability for the pump - I suppose. This one is buried. It is located at the very bottom of the PSP bracketing:
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Working from above, access to the lower bolt is nearly impossible on a fully assembled engine.
The images above show a SBC with most of it's auxiliaries removed. However, in an actual "on the fly" belt renewal procedure, things are considerably more cluttered (i.e. by the radiator fan, the fan shroud, drive belts, upper radiator hose, etc).
So, while working on the lower bolt, instead of working conditions like this:
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You are faced with something more like this:
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and remember, that's while both loosening and tightening it!
But what actually makes the tensioning of the belt more difficult than other set-ups is the dual adjusting slot configuration.
With a single slot and a pivot - you just kind of pull on the driven component and the belt tightens up. Then, hold it in place with one hand and clamp down on the adjusting bolt with the other. Done!
It may not sound hard, but to tension the belt on the PSP, the entire pump bracket must be
rotated about the pivot point. You cant just yank on the bracket and watch the belt go tight. If you simply pull on any one spot on the mounting assembly, the tendency is for one of the adjusting bolts to get jammed against the side of their respective slots. It feels like the bracket is not loose enough and so you back off on the bolts some more. Then you try to pull the bracket again - maybe this time in a different direction or at a different spot.
When and if you finally get some tension in the belt - even if it isn't as tight as you normally shoot for - it is human nature to just say "that's good enough". You hold what you have in place and tighten the top outer bolt. Then you have to climb under the truck and tightening the lower bolt.Then back up to the top and torque the pivot bolt.
All done! To test tension, you push your finger down on the belt between the water pump pulley and the PSP pulley. Nearly all the time you will find that the tension you had set is now not nearly as tight as it was. You know that you should really loosen everything up and do the job over again - but most people don't. They shut the hood and drink a beer.
That is my theory on why the power steering belt squeals so much.
