Chevrolet Repair: chev astro van 1988 power steering bracket, power steering pump, correct tension

Question
i have problem with the bracket that holds the power steering pump on my 1988 astro van. it keeps breaking . there is a strenthing bracket which connects at three points . one to the block the other to the exhast manifold and another to the power steering pump .there seems to a lot of stress somewhere because the main bracket which holds everything else is also cracked now .have replaced both main bracket and strengthing bracket once already but problem persists ,power steering seems to operate ok .new belt installed . do you think it might be the pump . new lines for pump installed . no noise from the pump .brackets purchased from chey dealer new .pump bleed by lifting front wheels off the ground and turning steering to opposit locks 20 times checked fuild level (ok).it has a automatic tensioner could that be over adjusted .if at all .if so how do i check correct tension .throws the belt off now because of the pullys are slightly out of alinement on a cold start . until i repeat the repair process again .when i purchased  the van .  the two bolts connecting the main bracket to the block bleow and behind the power steering pump had sheared off . replaced with studs epoxyed in now after having to drill old ones out.they haven't snaped yet.engine (z 4.3 six )uses  a lot of oil but seems to run ok .smokes at cold start  could  be due to worn vavle seats ( 150,000 miles )it also has air con .the configeration is , if look from the front of the vehicle .air con to the left , alt to the left and above air con, power steering to the right .  and down low .

any help would  save me from going mad

thank you for your time

Answer
Hi Jeff,
Forgive me for not answering sooner, but I was out of town on a firefighting assignment, and nowhere near a computer.

I am wondering if one of the pulleys might be bent, causing a severe vibration of the belt.
Check the idler pulley, and each of the other pulleys.
I doubt it is the pump itself, but it is possible.
Look at the belt while someone turns the wheels while not raised, to see if you can see the pump vibrating.

Van