2007 R500 in between two drives Looses POWER STEERING

Jul 23, 2017 | 07:58 PM

Dutch Dekkers

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2007 R500 in between two drives Looses POWER STEERING

Dear R Friends,

My 223,000 km/ 138,000 miles R500 from 2007 drove to Church this morning, all 100%. I park it, have lunch, and then my wife wants to take it for groceries: Power steering dead??

Again: Drive #1 all is 100% > Car sits for 80 minutes > Drive #2, from start up Power Steering is dead.

Fluid level is full; No weird sounds from the pump (you only hear the beautiful M113 engine buzzing); jacked both front wheels off the ground > turned L to R about 4 times > started the engine > did the same with running engine. No weird pump sounds (Brand new belt by the bye...). Sucked out 0.5 liter of the fluid > filled it up again with new fluid > same procedure > Power Steering remains stone dead.

??? Can a pump die when I eat lunch :-) ??

Forgot to mention. I have this R for a year now, and some 18,000 KM. Always when starting it, the power steering would be dead, until I would start rolling in the garage for about 2 meters and then it would come alive and work flawlessly. Maybe there is some sensor or so that controls when it should become active?

Any ideas???

Thanks so much for thinking along.

Dutch

Last edited by Dutch Dekkers; Jul 23, 2017 at 10:49 PM.

Jul 24, 2017 | 04:47 PM

marc hanna

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From: Nova Scotia, Canada

2023 GLK250, 1987 560SL

It sounds like your pump is dead. Have you tried revving the engine to see if the steering starts to work?

It likely was on it last legs when you pull into church and had enough pressure still in the system, but when you started it back up, it couldn't build pressure anymore.

Jul 24, 2017 | 06:46 PM

Dutch Dekkers

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Pump works fine...

Hi Marc,

Thanks for your input. The pump is dead silent in its running/operation. Also, when I replaced some of the fluid, I overfilled the reservoir and the pump beautifully (bit of a mess) pressed the fluid out through the lid seal, so it's clearly building pressure.
BUT... I did try what you said: Started the car > put it in neutral > rev'ed up to 1700 rpm (already quite some rpm for this v8) > no change: power steering still dead :-(

I'll hunt some further, but welcome input as always.

There's wisdom in the gathering of councillors,

Hans

Jul 25, 2017 | 08:57 PM

marc hanna

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From: Nova Scotia, Canada

2023 GLK250, 1987 560SL

Is the steering wheel really stiff? As in you have to use two hands and heave really hard to turn it?

Jul 25, 2017 | 11:33 PM

Dutch Dekkers

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Very stiff indeed...

Hello Marc,

It is very stiff indeed. At ultra low parking speed, with my big fat and thin tires, it is a two hand job for sure. If you keep some speed going it is doable for this Rocky Mountains guy, but certainly not for my wife. I spoke with the head of maintenance at my dealer, and he recommended to first check the high pressure output. He said in almost all cases it's simply the pump. Nobody in my town has a hydraulic pressure tester. We do have lots of mining industry oriented shops, so I'm sure I could have come up with a tester of sorts, but I choose to order the pump at my dealer instead.
I'll let you know the outcome.

BUT... why did you ask, Marc? You make me curious. It doesn't steer more heavy than I would expect. The R500 is quite a big heavy beast, and shoed with big tires (mine is for sure).

Thanks for thinking along, Marc,

Hans

Jul 26, 2017 | 07:16 AM

marc hanna

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From: Nova Scotia, Canada

2023 GLK250, 1987 560SL

Just confirming it's the pump. It's a pretty simple repair.

Jul 26, 2017 | 11:37 AM

Dutch Dekkers

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The pump... remains weird...

Hi Marc,

So your suspicion of super hard steering is that the pump is the cause (just like MB's technician things). I just find it so weird that a pump that is directly connected to a pulley would fail from perfect running to no power steering. That's my one worry in this $550 experiment. I wished I could test the pump output before spending the money.
Why would the pump sheer/fail between two drives... That remains a big Q for me. From working perfectly with me, to my wife having a dead pump upon driving away.

We'll see I guess... :-) The pump is ordered in.

Thanks, Marc,

Hans