Ridgerez Posted September 15, 2007 Share Posted September 15, 2007 When I first start the car in the morning and the engine is revving high, the steering is free wheeling...no resistance to turning as I back out of driveway. Within 5-10 seconds of this, when I turn to move fwd to the street, steering STIFFENS up. I have flushed the power steering and there was no improvement. What's the possible cause? '90 LS400, 251K miles. Otherwise runs great. Quote Link to comment Share on other sites More sharing options...
ko90ls Posted September 15, 2007 Share Posted September 15, 2007 might be the control valve which adjusts the power steering play based on speed. this or the fluid is low? maybe even check the steering rack filter Quote Link to comment Share on other sites More sharing options...
Ridgerez Posted September 17, 2007 Author Share Posted September 17, 2007 might be the control valve which adjusts the power steering play based on speed. this or the fluid is low? maybe even check the steering rack filter Would that be the valve under the alternator? The one with the two tubes leading into them (vacuum control valves?). Changed that last April...mine dripped ps fluid unto and damaged the alternator, so I changed both. And fluid isn't low, I check it damn near daily. Anyway, this morning, in 50 degree weather, steering was smooth for nearly 25 secs. I just don't understand my baby pooh. Quote Link to comment Share on other sites More sharing options...
qha_vn Posted September 18, 2007 Share Posted September 18, 2007 my 90 ls400 got similar issue, when rev is high i am driving a lexus, when rev is normal (600-700rpm) especially when i am parking the car or make a U turn, its like i am driving a ... truck also the power steering pump sounds like grn grn loudly when i start turning the wheel have it checked tomorrow, may be need a replacement Quote Link to comment Share on other sites More sharing options...
ko90ls Posted September 18, 2007 Share Posted September 18, 2007 check out this post before you buy a new ps pump. http://us.lexusownersclub.com/forums/index...amp;hl=steering Quote Link to comment Share on other sites More sharing options...
qha_vn Posted September 20, 2007 Share Posted September 20, 2007 i had the power steering pump replaced yesterday, the old one worn out and made so much noise. the 2hand SC400 replacement works great without the valve that lets some more air into engine at dead steering ends. Maybe i will be back to the shop and have them clean the solenoid filter. i think this filter is to regulate the amount of oil flow thus makes the steering stiffen in high speed. am i right? i also replaced the air con compressor as it was noisy, leaking. the 2hand repalcement works all ran me $650 happy owner now Quote Link to comment Share on other sites More sharing options...
Ridgerez Posted September 27, 2007 Author Share Posted September 27, 2007 check out this post before you buy a new ps pump. http://us.lexusownersclub.com/forums/index...amp;hl=steering Thanks for the link. Tuesday, 9/25/07, I took out and cleaned the p/s solenoid screen. Didn't look like that had ever been done for my 90 LS400, 251K+ miles. Was really dirty. Its easy to do if you know what to do. Of course, I had help. Solenoid is on drivers side, at bottom of steering column, under car. It has two wires sticking out. Disconnect wires at connector, where its fastened to solenoid. Used a long screw driver and hammer to tap open solenoid. Some ps fluid escaped (I was prepared for that). Cleaned screen in gasoline with soft tooth brush and compressed air to blow out dirty stuff. Put it back, filled ps fluid, did some bleeding by turning steering slowly from one end to other end, and road tested successfully. Steering is now so smooth. I don't miss hard steering of the past nine months. Quote Link to comment Share on other sites More sharing options...
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