This is commonly called morning sickness. What generally occurs in the 900 is that the steering wheel is harder to turn or actually "Catches" within the turning radius only when the vehicle is cold. Once the engine begins to warm the steering seems to soften and the catch within the turning radius disappears. The most cost effective repair is to replace the rack. Power steering racks can be purchased both new and remanufactured.
NOTE: Another issue that has been discovered has been documented by a good customer who has been kind enough to share his findings in the following letter: (Thanks Thornton Bryan)
"About 4 months ago, I noticed the steering on my 1992 900 turbo convertible didn't want to return to center. I checked the power steering fluid, which was a little low, and topped it off. Not much improved, and I took it to my local mechanic, who suggested a new power steering pump. If anything, the problem got worse. It was difficult to return the steering wheel after a turn, either to the left or right. I consulted the Saabsite, which led me to suspect .morning stiffness.. My mechanic replaced the rack, and the problem worsened. The only thing we could deduce was possibly a bad new rack. As my mechanic took off the rack, he noticed the lower U joint of the steering column (where the column connects to the rack) was frozen along one of its axes. My mechanics had seen one of these joints fail in 45 combined years of car work. TW reported never having seen this happen outside of collision damage. The joint was replaced, and all is well. I am very grateful to TW for talking with my mechanics, and helping to locate a suitable repair part for such an unusual failure". Sincerely, Thornton E Bryan III, MD
Thanks to Niran Fernando Canberra for contributing to this FAQ!
Similar steering wheel bind was observed in my Saab 9000 Aero 1994. I first thought it was the upper bearing near the Starter Switch/steering lock, but that was A OK. Then I assumed it was the power steering rack and beyond my capability. Eventually, the steering mechanic discovered the lower steering column roller bearing seized. This small needle bearing is found in the lower half of the collapsible column. Either replace this bearing or obtain a good 2nd hand lower shaft assembly and the rest is easy.
Thanks to William Turner for contributing to this FAQ!
This issue with lower steering column joint failure occurs in about 0.5% of vehicles in the 900 model range that I have seen. Most failures of this joint can be attributed to over zealous cleaning
with engine degreasers and high pressure washing of the engine bay. The joint can literally be internally degreased causing failure!! The upper joint has never been seen to fail in this manner being protected by it's location.
Pricing for 9000 POWER STEERING RACK & RELATED (steering & related)
Pricing for 900 79-94 POWER STEERING RACK & RELATED (steering & related)
Pricing for 99 POWER STEERING RACK & RELATED (steering & related)