Thanks for the information on the power steering system. I cleaned out the tiny filter and flushed the whole system and it works great, better than ever.
I took pictures of the filter while working on it. How do you want me to pass them to you so you can include them with this post.
Great pictures of the solenoid and filter screen. Does anyone know the part number for the filter screen? Lexus of South Atlanta has some part numbers on their diagram but I am trying to find a cross reference for the local Toyota Dealer to buy a new screen--old one tore very easily. The part numbers from Lexus/South Atlanta are not what the Toyota dealer needs. Also want to replace the o ring. Thanks
Update: Got parts from salvage yard.
Last edited by forHeisris; 07-21-14 at 12:23 PM.
Thanks everyone for the awesome posts they help tremendously.
I've had my 93 SC400 for just a few weeks and sprung into action chasing down a PS leak when I saw the alternator was pretty wet. Long story short the wettest part seemed to be just after the Air Control Valve (ACV) AKA Idle Up Valve on the two vacuum lines. Although I'm not 100% sure on this, I think ATF wasn't getting sucked upstream because I never had the smoke issues and everything upstream is pretty clean. I also don't know exactly how the Idle Up Valve functions but I'm pretty sure it doesn't blow out ATF! So assuming it had failed I got a replacement part at Napa for like $102. I'm not really into the plug job some people mentioned - I wanted to replace the functionality of the valve.
It's pretty restricted getting to the valve but I wrenched it off with a 17 from underneath. You can get just enough movement to break it free and then you can loosen it the rest of the way by hand. You need to pull off the vacuum lines first, which are also tough to access but you can work your way to them. My left hand seemed to have the best angle to get it done. Like everyone else says have a pan underneath because you'll leak out about a pint of ATF. Someone said to cover the alternator but on the 93 SC400 that didn't seem to be a problem.
It also helped up-top to take off the air intake part (and I don't know what its called) that sits between the air filter box and the the part that's on top of the intake manifold. On the SC400 its in the way of you and the PS pump so its pretty obvious. By having the top clear I could see down and was able to see what I needed to do and also was better able to clean up some of the mess from up top. Since it only takes a couple minutes to get it off I thought it was well worth the effort.
Add ATF and follow the procedure to bleed air from the PS system. I took it for a test drive and everything underneath seemed dry, however I will watch it closely the next week or so because I wouldn't be surprised if there isn't something else going on.
Like another leak I found in the PS! On the driver side one of the lines had a drip, so I tightened the band clamp. Problem solved, right? No - after the above test drive the leak was worse! After closer inspection I noticed the band clamp was like two sizes too big for that size of line. What clown would do this? Ugh so I replaced it with a smaller clamp and after the test drive this looks to be OK too. But I will be watching both like a hawk over the next week.
One final note. Be nice to yourself or to the next guy by doing the job right and don't do a hack job (like too big of a clamp) and when you are tearing into something, go the extra mile and clean up since you now have access. Cleaning solutions are pretty cheap and you'll have done a nice tight job.
My two leak fixes from yesterday July 26 2014 have held. The garage floor is bone dry. I made it bone dry by cleaning up all my spills with Quickrete concrete. The box stores sell little buckets for for about $10 for patching concrete. I sprinkle it into the spills, if they are light I will grind it into the spill with my foot. For larger spills I will put it on a little heavier and sweep the spill up with a broom. I find this stuff works better than cat litter or other cleaner uppers.
I am getting the white smokes on start up and losing powering steering fluid so after looking at several forums its seems I should try to replace the the air control valve part 17630-16040. Does any have a link on step by step for doing this? I have a 93 Lexus LS400.
i have a 1994 LS400 and i want to replace the power steering pump and alternator.....is this a easy job for my mechanic? any tips on this procedure is greatly appreciated! i will be using oem parts....
Today i went and pulled the solenoid to clean the screen. Was very easy to remove do lose about a pint of fluid. removed the ring with the screens. It was clogged up in many spots. Now the screens are very fine and are in 6 or 8 widows around the ring. Wish i had taken a photo.
Mine had holes in about 3 of them not surprised. I used the 3M cleaner listed in this post. Worked like a charm just blasted away the build up. Let it dry reassembled.
Flushed the system used about 7 qts to make sure i had it all flushed out.
Haven't taken her for a ride yet but hope it does fix the intermittent loss of power. Happens random but when when i slow down to turn.
May have to look for another good screen somewhere.
I had a customer a few years ago that had a problem with her steering that drove me nuts, it seems that every now and then the steering would lock up and she would have a hell of a time turning then after the car was turned off and back on the problem went away, after a few visits to my shop I found her problem, it was a bad hose from the inside which had a separation of the hose and only some times would block the fluid from returning to the pump I only found the solution after replacing the hoses because of a small leak in one of the hoses. she came back after about a week and thanked me for fixing her car.I just got lucky
I have read through this and just replaced my PS pump and cleaned the solenoid screen and I have a couple questions. I would preface this by saying that the idle control system seems intact and no traces of oil in any of the lines, the idle up system never functions in spite of appearing intact.
1. Since I purchased the car the steering was heavy and reading through the posts I found that it would be necessary to clean the solenoid screen. I performed this screen cleaning today and removed the solenoid just as described in the write-up but what did not realize for a few moments is the solenoid was unscrewing and leaving the large nut on the rack and I backed the solenoid out about 0.25" before I realized this and recalled the whole thing was to come off together. I removed it with the nut and ran it back up before cleaning and re installing it. Did I eff up my solenoid? This service made no difference in the heavy steering is why I ask.
2. I replaced the groaning PS pump today, just fell in love with that bottom bolt location to! The car is so silly quiet now, I love it. BUT... I took the engine cover off the top of the engine and noticed that air control valve on the side of the steering pump has a vac line that runs up to the intake horn where there (used to be) a nipple there that the vac line went to. It sits adjacent to a slightly larger outlet that heads across the front of the engine down the drivers side. Since that nipple is gone and someone already tried to fix it with epoxy and failed can I "T" into that bigger line right there with it and plug it in that way in hopes of regaining function of the idle up system?
I just hate seeing hose nipples on plastic parts, I know this has to have happened to other folks and there must be a workaround. I already sealed up the hole in the intake horn where it broke off and plugged the line until I find a suitable workaround.
I searched and I couldn't find answers to these two so I apologize if I missed it somewhere,