2006 ML 95k miles

Beautiful 70 deg day and out for a nice drive with the windows and sunroof open. I haven't drove it much lately. I usually drive easy and mellow - enjoying the ride. I was on a nice long straightaway and i decided to open her up a little. Clear out the cobwebs in the ol V8. I open her up... accellerate to ~75 or so... I go to slow down for the upcoming right hand turn. Slowing down no problem - but i noticed the power steering isn't working. It is hard to steer. I make it around no problem but i am looking for a place to safely turn off to check.
She has never done this previously.
I pull over thinking either the belt slipped or broke.... or the pump is dead.... maybe the reservoir is empty!?!
All okay. Fluid is clean and full. Belt is fine. no leaks, no smell or noise, all okay. I shut it off and sit about 5 min. No change. no power steering.

I am 3 min from home. I start again and turn around (low speed)--- make the first turn and i feel the PS come back. I thought i heard a faint click while driving. She steers normally. no issues.
zero messages on dash. everything else seems normal. I looked underneath. Nothing wrong.

Anyone ever heard or seen this?!??! I already planned to replace the stained and original reservoir later this week along with the fluid.
I know there is a small filter screen in the reservoir - could that be causing the sudden loss? I parked her for now.

I appreciate your thoughts.

 

Be sure to use DEXRON II or III

 

tammap, Can you explain what that printout is? Some Lexus database of repairs? I had dealer replace my fluid around 2.5 years ago, just because I never had before. My 2005 has 165k miles. The problem seem common, or not rare, but is it the pump that reeds replacing, or the reservoir? Is reservoir filter clogging the main problem, and should my fluid change help prevent, or does the reservoir need to get replaced at some point even with a fluid change? I'm wondering if there are proactive steps or if this is just age/mileage related. I'm not sure how expensive a repair is if this destroys the steering rack, (or is it just the pump), but I'd rather not find out. Thanks

 

I would try pulling the reservoir out and checking to see if fluid is actually making it through the filter. If not you could try cleaning it or replacing the reservoir. If that's not the issue then I'd look into the pump. As long as the rack has no visible damage and isn't leaking then I'd stick to looking at the reservoir, pump, and lines. That printout is just showing people's fixes for loss of power steering in these cars.

 

Odds are the screen in the reservoir is blocked but not completely. When the return line dumps fluid in the bottle along with the temperature variation and fluid sloshing around from road vibration, there is no clear pattern to the problem. My 04 did this kind of thing. The rubber lines in the system deteriorate with age and start contaminating the fluid. A way better design would have been to make the screen replaceable instead of having to replace the bottle which is crazy expense. Flush with new fluid before putting in the new bottle. However, unless you replace every single rubber line in the whole system, it will clog again one day that will come sooner than the around 20 years it took to clog the factory installed screen. I thought about adding an aftermarket serviceable filter in the system on the return side but have not gotten around to it. That is way less than replacement of all OEM rubber lines which come with the metal lines and cost big bucks.

 

The printout shows a repaired database from Identifix of indy shops that share their vehicles's issues with the confirmed fixes.

The P/S reservoir clogging is the main problem leading to P/S pump failure. A serviceable inline filter is an option to save time from having to clean out the P/S reservoir filter regularly.

The Toyota/Lexus P/S pump filter screen leaves much to be desired, see the attached

 

It happened in a slow turn in a parking lot...click and cured. Then It happened again a day layer....Then I discovered the problem...simple and cheap./

I had too many keys on my key ring and it was fowling the cruise control stalk. The second time it pulled so hard on the stalk that it popped out the trim piece around it.
Took some keys off the key ring and no more problem.

 

I have heard that there is a filter integrated into the PS reservoir bottle. It's not a serviceable item, and sometimes they get plugged. I would look into that.