94V8coupe

New owner here of a very nice '95. The steering in this brute feels "heavy" to me. My girl drives a '94 SC (which I have obviously had the pleasure of driving - and maintaining - and repairing ) and if you are at low speed, the steering effort is super light. Beautiful for tight turns and parking lot maneuvers. Feels like my old Lincoln town car. The faster you go, the more effort required. Variable assist. It's a beautiful thing. Is my '95LS supposed to have this feature? If it does it sure doesn't feel like it's working, that's for sure. I figure the steering should be light as a feather in the BIG sedan. Even more so than the sport coupe.

fondu

Ah yes, no better way to start your LS ownership then with some power steering issues

You are correct that it should be effortless in very low speed situations and then tighten up the faster you go. The EVO unit on the steering rack controls this function. I would start by cleaning the screen in the EVO unit and power steering reservoir then change/flush the fluid while you're at it. If that doesn't help then start looking at the actual hardware such as the pump, rack, lines. At this age you can't really rule any of it out along with the fact that the power steering is the most common issue on these cars.

Hopefully it is a simple fix!

94V8coupe

Thanks for the response.
Yeah, found out the hard way about the leaking pump that takes out the alternator with the woman's SC. Bought a "rebuilt" unit (what a joke) thinking that would take care of it. Naively thinking I might actually get what I paid for ... it leaked worse than the original, and the monkey that did the install did not use a new copper crush washer on the high pressure line it leaked form there as well.
Luckily I kept the original pump. Got the updated rebuild kit from Lexus ... rebuilt the pump myself, with surgical precision and cleanliness, put in in myself, WITH a new crush washer. That was eleven years ago and it has not lost a drop,
What does EVO stand for and where might it be located on said rack? Does the system need to be drained to work on it?
We can always hope but it rarely works out that way
It's not like it's un-driveable or anything ... just bugs me knowing how it should and can be.
Wouldn't have known any better if I didn't have experience with the other car.

fondu

I think it stands for Electronic Variable Orifice.

Here is a picture. You will have to remove it from the rack to get the little screen out.

This link below should give you much of the info you need on these steering systems. When I started to get a noisy pump, leaking high pressure hose and worn out rack I ended up going with all new components. I tried a fluid exchange and cleaning the screens first but it didn't help much at all. It was not nice for my wallet but I do know I won't have to deal with it again for quite some time.

https://www.clublexus.com/forums/ls-...ing-bible.html

bradland

It's the lowest port of the PS system so it will drain fluid when removed. I've always considered it a positive and used it as a convenient way to drain the system when replacing fluid👍
Just be careful while removing/cleaning/reinstalling as I'm sure it's an obsolete part.

It sounds like you have experience with LS/SC PS systems so I'm sure you know it's a multi-headed monster. You can chop one head off but that doesn't kill the beast. The function of the EVO solenoid starts at the pump with the ACV (air control valve). When the pump is under load pressure is exerted on the ACV causing it to "crack a window" allowing air into the intake. This additional air raises RPM's causing the pump to spin faster and move more fluid through the system. Unfortunately, the tiny O rings inside the ACV become brittle with age allowing PS fluid to escape along with the air entering the intake. More fluid through the ACV = less air and the system suddenly isn't working as designed.

Clean the EVO screen and do a visual inspection of the ACV. If the 2 hoses attached to the ACV are wet it's likely leaking.

fondu

+1 on checking the ACV. That could also be a simple fix for the issue you are experiencing.

94V8coupe

Excellent. Thanks very much

bradland

I think we've all experienced the ACV white puff of smoke at start-up. If you haven't you might not be looking... 👍

94V8coupe

You could say that but nothing south of the pump itself and the hoses.
Was doing a bit of searching and reading on this. May as well start here since I can check this part out without being on the cement on my back.
I can say up to now (since I've owned it) there is no PS fluid loss of any kind (leaks or burning) so if the problem was here I guess it would have to something mechanically wrong with the valve other than bad o-rings. In fact, this car has no leaks of any kind, anywhere. The care taken by the last guy that owned it was extraordinary.
Roger that

bradland

May as well start here since I can check this part out without being on the cement on my back.
It's mounted to the bottom of the pump.

I can say up to now (since I've owned it) there is no PS fluid loss of any kind (leaks or burning) so if the problem was here I guess it would have to something mechanically wrong with the valve other than bad o-rings. In fact, this car has no leaks of any kind, anywhere.
They all fail eventually. If yours hasn't yet you are in the elite sub 1%. The amount of fluid loss through the ACV is rather minimal but it happens.
https://www.clublexus.com/forums/ls-...ring-pump.html

94V8coupe

Of course it is.

My girl's SC has not lost one drop of PS fluid since I rebuilt the pump more than a decade ago. Count her car in that 1%.
If it's burning any, it is so minute it is undetectable.

bradland

That's interesting because the ACV on an SC is not mounted directly to the pump like an LS400. It's mounted elsewhere on PS line. LS400's are basically guaranteed to leak through the ACV but it does not happen on LS430's. When the 430 was designed they moved the valve away from the pump to a nearby PS line...
Hmmm

94V8coupe

Well isn't that interesting. Makes sense because I had no recollection of having to mess with a part that looked anything like that when I did the rebuild. The variable assist works awesome on that car. even with the smaller wheel the steering is feather-light when you're going slow.

Hell, that car is just awesome in general. And extremely trouble free. It doesn't owe anyone anything.

That being said ... does the dang pump have to come out to get at this little S.O.B. on the LS?

bradland

Technically no, BUT I'd advise against removing it will still on the car.
If you remove it you want the threads nice and dry when re-installing. Aka have it on a bench nice and clean.
I used a dab of this as well-

400fanboy

Cherish those cars man. Those who do not leak or burn any oil from any system are becoming more and more rare. Well built these cars are, but nothing is immune to neglect.