Challenging Power Steering Issue Has Me Baffled

[newlexman]

HELLO EVERYONE,

I recently purchased a 1991 lexus ls 400 with a very tight steering wheel on parking lot turns , backing up, u turns , basically at low speed. I had a friend, who is an american car mechanic, replace the power steering pump. Did not work. Then he replaced that one thinking it was defective. No luck. Then I did the rack and pinion. Next we did the air valve and replaced the pump again. It was of course easier but still more often than not times it is still stiff on slow turns, uturns etc..... So after that, we replaced the high pressure hose to see if that would solve the problem. No luck same conditions. Now when he did the rack he told me that when the car is in the air it operates fine when turning the wheel no hard resistance at all. It is when it is on the ground it is a problem. After repairs he explained to me that parts meet oem or better standards per warranty info. I dont know who manufactured the parts. I know the rack was from napa. Alas, I am lost , a bit discouraged, but not a quitter.

What else is there to do.???????

Please respond

Thanks

[pishta]

HELLO EVERYONE,

I recently purchased a 1991 lexus ls 400 with a very tight steering wheel on parking lot turns , backing up, u turns , basically at low speed. I had a friend, who is an american car mechanic, replace the power steering pump. Did not work. Then he replaced that one thinking it was defective. No luck. Then I did the rack and pinion. Next we did the air valve and replaced the pump again. It was of course easier but still more often than not times it is still stiff on slow turns, uturns etc..... So after that, we replaced the high pressure hose to see if that would solve the problem. No luck same conditions. Now when he did the rack he told me that when the car is in the air it operates fine when turning the wheel no hard resistance at all. It is when it is on the ground it is a problem. After repairs he explained to me that parts meet oem or better standards per warranty info. I dont know who manufactured the parts. I know the rack was from napa. Alas, I am lost , a bit discouraged, but not a quitter.

What else is there to do.???????

Please respond

Thanks

Things to check, plugged filter in servo (on rack, but not included in a new rack) or front strut mounts. They are the bearings that your car struts ride under. When you turn, the struts turn under these large bearings. If they are shot, youll get a huge drag on the steering gear and possibly a hard steering wheel. Mine is kinda tight when stationary too, chalked it up to a "road feel" type of P/S system, not like the one finger steering of an American car.

[SKperformance]

I guess you already had an alignment after the rack?

I would throw a transmission inline filter from wix to make sure the whole thing is clean and then sea foam the engine to make sure the vac is up to par.

[newlexman]

HELLO EVERYONE,

I recently purchased a 1991 lexus ls 400 with a very tight steering wheel on parking lot turns , backing up, u turns , basically at low speed. I had a friend, who is an american car mechanic, replace the power steering pump. Did not work. Then he replaced that one thinking it was defective. No luck. Then I did the rack and pinion. Next we did the air valve and replaced the pump again. It was of course easier but still more often than not times it is still stiff on slow turns, uturns etc..... So after that, we replaced the high pressure hose to see if that would solve the problem. No luck same conditions. Now when he did the rack he told me that when the car is in the air it operates fine when turning the wheel no hard resistance at all. It is when it is on the ground it is a problem. After repairs he explained to me that parts meet oem or better standards per warranty info. I dont know who manufactured the parts. I know the rack was from napa. Alas, I am lost , a bit discouraged, but not a quitter.

What else is there to do.???????

Please respond

Thanks

Things to check, plugged filter in servo (on rack, but not included in a new rack) or front strut mounts. They are the bearings that your car struts ride under. When you turn, the struts turn under these large bearings. If they are shot, youll get a huge drag on the steering gear and possibly a hard steering wheel. Mine is kinda tight when stationary too, chalked it up to a "road feel" type of P/S system, not like the one finger steering of an American car.

[newlexman]

HELLO EVERYONE,

I recently purchased a 1991 lexus ls 400 with a very tight steering wheel on parking lot turns , backing up, u turns , basically at low speed. I had a friend, who is an american car mechanic, replace the power steering pump. Did not work. Then he replaced that one thinking it was defective. No luck. Then I did the rack and pinion. Next we did the air valve and replaced the pump again. It was of course easier but still more often than not times it is still stiff on slow turns, uturns etc..... So after that, we replaced the high pressure hose to see if that would solve the problem. No luck same conditions. Now when he did the rack he told me that when the car is in the air it operates fine when turning the wheel no hard resistance at all. It is when it is on the ground it is a problem. After repairs he explained to me that parts meet oem or better standards per warranty info. I dont know who manufactured the parts. I know the rack was from napa. Alas, I am lost , a bit discouraged, but not a quitter.

What else is there to do.???????

Please respond

Thanks

Things to check, plugged filter in servo (on rack, but not included in a new rack) or front strut mounts. They are the bearings that your car struts ride under. When you turn, the struts turn under these large bearings. If they are shot, youll get a huge drag on the steering gear and possibly a hard steering wheel. Mine is kinda tight when stationary too, chalked it up to a "road feel" type of P/S system, not like the one finger steering of an American car.

I have done the alignment after the rack as well. I have never driven a lexus before and I am use to small 4 cyl cars. Am I possibly overreacting. Does everyone have a bit of an ordeal with their 400s with harder than small car turning or how can I tell if the those front strut mounts are worn?

[glenmore]

I have a 1990 and the P/S is one finger light. I am at 155m and the PO redid the whole system back at 100m at the dealer.

Maybe the other poster is referring to something else but the strut mounts are just bolted to the frame of the car and just serve as a rubber isolator between the road and passengers.

My guess is that the pump you've used is not up to spec. How is your belt drive system? Belt tensioner indicator where it should be?

glenmore

1990 LS400

1991 300CE

2000 C280

[newlexman]

I have a 1990 and the P/S is one finger light. I am at 155m and the PO redid the whole system back at 100m at the dealer.

Maybe the other poster is referring to something else but the strut mounts are just bolted to the frame of the car and just serve as a rubber isolator between the road and passengers.

My guess is that the pump you've used is not up to spec. How is your belt drive system? Belt tensioner indicator where it should be?

glenmore

1990 LS400

1991 300CE

2000 C280

If that is the case how can I tell. I am not a mechanic. I have to trust my mechanic to do the right thing. He was honest in saying he could not find a repair manual for the vehicle, but he always does a good job on all my other previous cars.

[newlexman]

I have a 1990 and the P/S is one finger light. I am at 155m and the PO redid the whole system back at 100m at the dealer.

Maybe the other poster is referring to something else but the strut mounts are just bolted to the frame of the car and just serve as a rubber isolator between the road and passengers.

My guess is that the pump you've used is not up to spec. How is your belt drive system? Belt tensioner indicator where it should be?

glenmore

1990 LS400

1991 300CE

2000 C280

If that is the case how can I tell. I am not a mechanic. I have to trust my mechanic to do the right thing. He was honest in saying he could not find a repair manual for the vehicle, but he always does a good job on all my other previous cars.

Also where should i be getting a pump from that is up to spec but not at lexus prices

[wwest]

There is a steering damper, "shock absorber" mounted across the bottom of the engine that may be your problem.

It could also be, possibly, the macpherson struts.

[pishta]

I have a 1990 and the P/S is one finger light. I am at 155m and the PO redid the whole system back at 100m at the dealer.

Maybe the other poster is referring to something else but the strut mounts are just bolted to the frame of the car and just serve as a rubber isolator between the road and passengers.

My guess is that the pump you've used is not up to spec. How is your belt drive system? Belt tensioner indicator where it should be?

glenmore

1990 LS400

1991 300CE

2000 C280

I stand corrected, the front suspension is not pivoting on the strut mounts, more common on a front wheel drive car. the power steering pump puts out a finite amount of pressure, that should be able to be measured out of a port or even the output port of the pump. Im sure a big Lexus manual may have the pump pressure spec handy for your mechanic to reference. a slipping belt due to a bad tensioner would howl like a wolf once a load is put on it, you would know.

[93ls400walt]

There has been a few threads on power steering. Some have talked of de-airing the system after a R&R of any part. They put the front wheels off the groud and remove the PS res. cap then turn the steering wheel ( with the engine running ) to the right then left to the stop point of each turn. Doing this around 15-20 times the remove any air with-in the system.

Also, not sure if in your post that you had the screen filters cleaned.one in the bottom of the res. and one in the selonoid ( sp ) . Use the search feature.

[newlexman]

There has been a few threads on power steering. Some have talked of de-airing the system after a R&R of any part. They put the front wheels off the groud and remove the PS res. cap then turn the steering wheel ( with the engine running ) to the right then left to the stop point of each turn. Doing this around 15-20 times the remove any air with-in the system.

Also, not sure if in your post that you had the screen filters cleaned.one in the bottom of the res. and one in the selonoid ( sp ) . Use the search feature.

Thanks I will see if my mechanic can try these and I will get back with you . I appreciate everyones willingness to offer a solution. This forum is awesome!!!!!!!!!!!!!

[nc211]

$20 says it's that tiny screen in the power steering solenoid. And another $50 bucks says you're gonna be really ticked off when you find out how easy it is to clean it and it fixes your issue and you realize how much money and effort you spent trying to fix this, only to realize it's a stupid tiny dirty screen that is easily serviced. Welcome to the club amigo...i did the same thing with my suspension issues.

search "solenoid", and you'll see the threads.

[elvis]

HELLO EVERYONE,

I recently purchased a 1991 lexus ls 400 with a very tight steering wheel on parking lot turns , backing up, u turns , basically at low speed. I had a friend, who is an american car mechanic, replace the power steering pump. Did not work. Then he replaced that one thinking it was defective. No luck. Then I did the rack and pinion. Next we did the air valve and replaced the pump again. It was of course easier but still more often than not times it is still stiff on slow turns, uturns etc..... So after that, we replaced the high pressure hose to see if that would solve the problem. No luck same conditions. Now when he did the rack he told me that when the car is in the air it operates fine when turning the wheel no hard resistance at all. It is when it is on the ground it is a problem. After repairs he explained to me that parts meet oem or better standards per warranty info. I dont know who manufactured the parts. I know the rack was from napa. Alas, I am lost , a bit discouraged, but not a quitter.

What else is there to do.???????

Please respond

Thanks

newlexman,

There is an electronic module under the dash on the left side that controls the amount of assist that the power steering gets at low speeds. Mine went out on my 1991 LS400 and it was like driving a truck when backing out of a parking space. It controls a solenoid on your steering rack. It was a few years back that I replaced it. I think the part from Lexus ran about $110. Its a little hard to get to but do-able. It just plugs in. Its called a "power steering ECU". There are some diagnostic tests that are called out in the Lexus shop manual. I just replaced mine and instantly, back to good power steering! It could also be your solenoid (on the rack) or a plugged filter screen in the solenoid itself, both easy fixes. Or a disconnected cable to the solenoid. Right now, I would try the ECU module.

[fblonk]

Hello,

I have a 98 LS (2) one with 130K and one with 60K. The 60K steering is easier than her sister. I have a friend at lexus. He explained that the valve on the steering rack has a screen in it. the more plugged this screen gets, the stiffer the steering. try removing the valve and cleaning it out. see if this helps.

Fblonk

[91LexusLS400]

I've had the same experience with my 91. Replaced just about everything and cleaned the screens twice. If it's cool outside in the mornings the power steering works for about 5 seconds, then back to annoying the rest of the day. I saw a thread about a filter being installed near the resovoir. I'll probably clean the screens a few more times and try the filter.