Originally Posted by Wasser
Are you absolutely sure the piece of hose you used is high pressure?
I've seen auto parts stores try to pass off fuel line as "high pressure" Good auto parts stores actually sell P/S hose but, you have to ask for it specifically.
The hose you used could be the incorrect style and collapsing when hot.
It is more likely that the parts store gave him gas hose instead of an oil resistant hose.
There is specific power steering hose for return applications (other than the hose assembly with the metal tubes attached) but we also used to sell transmission hose which would work well as it is also oil resistant and was cheaper.
Gas hose is not oil resistant and will soften & bulge before it makes a mess out of everything, however this is what most people buy.