Pagong

Last year (about 6 months ago) I replaced my P/S pump (reman)along with the lines on my 1990 LS400. It was making a loud noise after the install. I was told to drive it for a week and when parked just turn the wheel lock to lock to get the air out of the lines.

Okay so I did that, but the noise never went away. It would be really loud on cold starts only! After the car has warmed up the noise goes away .

I took my car back to my friend's shop who did the install and replaced the pump with another one and the power steering was totally gone!
And now they installed the 3rd pump hoping that they have sent us a bad pump and guess what?! The thing still makes noise and power steering is gone!

What else could fail in the power steering system of an LS? My friend thinks that there is a solenoid that probably needs to be replaced. Anybody here knows?

Kinda stumped right now guys...verhere: HELP!


Cliff Notes:
1. replaced pump and lines
2. makes loud noise ONLY on initial start of the car, when it warms up it dissappears
3. replaced pump...problem still there but now p/s is gone
4. replaced the pump again...problem is still there
5. ....what can cause the p/s pump to make noise during start ups only?

Lexmexico

What kind of PS fluid was put in?

ligflava

how old are the belts? are they in good shape? i've heard of worn belts being noisy and then quieting down once it warms up.

good luck.

Pagong

Lexmexico- As for P/S fluid, it is just your run of the mill synthetic ATF.

ligflava- And for the belts, it was not showing any cracks or age so it was left untouched. it couldve been just the belts when the problem first happened. But now the power steering is completely out! After it was replaced with a new pump.

So is there anything else in the power steering system that can fail to make the p/s disappear?

ligflava

there might be a solenoid that could have gone bad. also, have you checked the fuse panel to make sure there isn't a fuse for the PS that blew?

also, i'm not sure if the 90 LS has this, but some cars have speed sensitive steering where PS boost is cut at higher speeds. you might have a speed sensor connected to the transmission which failed, causing the solenoid to not activate the PS pump.

if you don't have a service manual, this problem might be best diagnosed by a good toyota/lexus mechanic.

good luck!

VVT-i

Make sure to bleed all the air out, by filled up the resovoir and turn the steering from end to end a few times with engine off. Then start the car up and turn the steering a few more time while fill up the fluid to get all the air out.
There's a solenoid on the driver side of the steering rack with 2 wires attach to it. You will have to remove the solenoid and clean the screen( whilte plastic screen). I think Herm did some write up on one of his post about PS pump.

Pagong

Thank you guys!

Found out today that the solenoid is bad. It was either getting a new solenoid from Lexus at $1000 or get the whole rack and pinion steering for $750 with the solenoid attached to it.

Should I try cleaning it out first? Or is this a common problem for a car this age?

Erwel

It might be the crackchaft and the ps pulley is not aligned. it will cause the belt to squick and force the
p/s pulley bearing to get loose causing p/s pump failure. just a thought

Erwel

hey,

the Philippine flag is cool.
I am a filipino too.
glad that you found the problem

later

Pagong

kamusta erwel?


Anyhow, i am going to try cleaning that screen off first before buying the parts.

If it doesnt fix it I might have to get the rack and pinion since it comes with the solenoid that I need.

JPI Racing

DO NOT BUY THE RACK YET!!!!
Tell your friend to check for these things:
1) Clean out the reservoir really good....I mean really good..There are junks in the reservior
2) Remove the power steering pump and check for the pressure switch. If there is air in the powersteering steering system, this switch would just shut down and you don't have power steering
3) There is a screen on the rack. Remove the screen and clean it off
4) Flush your lines....to get rid off the junks....
Do all of the items listed above and you don't have to spend $1000. Let me know if you need any further assitance.
JPI

Pagong

Thanks JPI...

I already let him know about the mesh screen that needs to be cleaned..so we are going to check on that on Monday. I will make a print out of your suggestion so I can take it to him.

Lexmexico

There could be some blockage of old fluid somewhere in the system. After meeting my friend with a 91 LS400, he said he had a similar problem and Toyota could not figure it out. I use Vaolvine Powersyn PSF (and also its brake fluid) in my 99 RX and it turns and brakes much easier (and with almost no noise).