When I replaced my entire power steering system a few years ago, it did the same thing as well as front brakes locking up way to easily. Somebody recommended that I replace the Proportioning Valve and re-bleed the system, and that fixed it immediately. Not sure if it was the valve or the re-bleed. After replacing all of the power brake and power steering parts and pieces under the hood I knew something would go wrong.
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?