Loss of power assist can be caused by a worn power steering pump or wear in the rack and pinion steering gear. If the power assist was lost when turning in only one direction at first, then the other direction weeks or months later, that can only be caused by the steering gear, and it will have to be replaced. The clue is the power assist, at first, will return when the engine warms up, typically in 10 - 15 minutes.
If the power assist is lost in both directions at the same time, it could be due to the pump or the steering gear, but if it's the pump, most of the time the power assist will return when you raise engine speed a little. If it does, it's the pump.
GM had a huge problem with internal leakage in their steering gears in the mid '80s to early '90s. Their fix was to install a new spool valve in the steering gear. That did not address the cause, which was wear to the aluminum housing. The intent of the fix was to get the car out of the 50,000 mile warranty as cheaply as possible, then it became the owners' responsibility to have the car fixed properly, which was to replace the steering gear.
The aftermarket rebuilder industry, Moog, in particular, does a real good job of correcting the design flaw. They install a stainless steel sleeve so the teflon sealing rings won't wear grooves into the housing and cause a repeat failure. Those rebuilt rack and pinion assemblies cost about one fourth of what a new steering gear costs, and they have a much better warranty. The car will need to be aligned after replacement of the steering gear.
Wednesday, April 16th, 2014 AT 11:56 AM