Added a P.S. cooler and blew my rack. Why?

So I purchased a complete LT1 converted '85.5 944 with Ford Hydroboost, PSC remote reservoir, and GM power steering pump. Everything worked, except I noticed there was no cooler for the power steering. I knew that wasn't smart. I had a good transmission tube cooler already, so figured I would install it.

Just for curiosity sake, I installed a temperature gauge and sender in the return line to see how much the cooler helped. Before adding the cooler, it was getting up to 230*F quickly and holding there. I plumbed in the cooler into the return line and temps were reduced to 170*F.

Unfortunaltely the power steering pump began making noise as soon as the cooler was installed. I tried several attempts to bleed the system, and after a few test drives I blew the power steering rack. :-(

What did I do wrong?

Thanks!
Rob

Let me add the rack was clearly rebuilt recently before I aquired the car. Very clean and a fresh coat of paint. So this wasn't a case of old seals or anything.

I assume the cooler is installed after the rack on the return to the reservoir. If it is restricted it could add back pressure to the rack seals as well as starve the pump.

I installed the cooler in the return line between the PSC remote reservoir and the pump.

It could indeed be restriction caused by the cooler, but how else would you install a power steering cooler?

I'm rebuilding the rack now. Once that's done, I'll delete the cooler and hope for the best.

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If I understand correctly you have the cooler between the reservoir and the pump, which is the suction (feed) line TO the pump. The suction line cannot have any restrictions. The cooler should be on the return line from the rack to the reservoir.

Thanks for that. I think you're right. That was probably the problem!