Power steering issues ML350 , lucky or not?

[GON]

This thread is indirectly connected to the below thread:

Thread 'Partial power steering fluid exchange at Wal Mart - McGiver style.'

Dec 23, 2023

Have a sticking power steering on a Mercedes. I am 1200 miles from home, and it is a Saturday afternoon.

I believe the problem is a Mercedes power steering proportional valve. Fairly simple to replace. $300 for the OEM part at Rock Auto. Amazon sells knock offs for $35.

As I am only local until Christmas day, decided to do a partial exchange of the power steering fluid. This method takes just a few minutes, all the tools and supplies at Wal Mart. Did the partial fluid exchange in the wal mart parking lot.

Key to this was the Prestone coolant tester. Did a flawless job of extracting...

• GON
• Replies: 35
• Forum: Mechanical/Maintenance Forum

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Last December 2023, the steering became very hard to turn on a 2010 ML 350 with 105k miles. A Google search pointed to a common and easy to fix issue, a speed sensor on the rack.

Purchased the OEM speed sensor, but never found time to replace. From time to time I would like for the sensor on the ML350, but could not locate it. I thought I would lay on my back and replace the sensor without jacking up the car.

8k miles later, my arms are hurting from no power steering. Last Sunday I decide to do the repair right. I put the ML350 on jack stands, removed the wheel well covers. I can't locate the sensor anywhere. More research identified the speed sensor was a option, and this car didn't come with speed sensitive steering.

Back to step one. First thing I do is perform the MB power steering bleed procedure. When I do this, unexpectedly a.large quantity of power steering fluid exits the power steering reservoir. Hmmmmm.

The bleeding did not correct the problem. I dona visual inspection, the power steering reservoir, power steering pump, and rack all look great, and are dry with the exception of the fluid exits from the bleeding.

Did more research, and some indications that the joint that connects the steering wheel to the rack can fail. I soak the joint in pb blaster, drive for 30 minutes, then soak the joint in lubrication. Hard steering still present.

Do more research, and most forums would say the power steering pump is bad. Hmmmmm. Also read the power steering reservoir has a screen the clogs that causes multiple weird issues. This makes sense, that if the reservoir screen was clogged, the bleeding procedure would push fluid released from pressure out of the reservoir.

I dedice to replace the power steering reservoir. I drive 100 miles to the MB dealership, special order part. I order the part and start to drive 100 miles home

Halfway home, the power steering problem goes away. For nine months and 8k miles, the problem has been static. Order the part and one the way home, the problem goes away.

The bug question is, lucky or unlikely....

 

[Boomer]

Very interesting! (Said with a German accent!}

Seriously, sounds like a piece of gunk broke loose from where it was restricting the flow. Probably swirling around in your fluid ready to clog up another orifice. Maybe would be good to drain the PS fluid again.

 

[Astro14]

It was always the reservoir.

So, lucky? Not really…you spent the $$ on that proportioning valve. If you can get that back, then, perhaps, yes, lucky.

 

[Astro14]

Incidentally, the Volvo XC 90 in my signature, has a built-in filter in the power steering reservoir.

The SL 600 has the filter as an integral part of the reservoir, too.

The S600 has a separate power steering filter in the return line to the reservoir. It’s easy to change the filter while keeping the reservoir. This is useful because the reservoir is combined with the ABC suspension reservoir, and a real pain/expensive to change.

This does make me feel good about installing a magnefine power steering fluid filter in the return line on all the rest of the Volvos…

 

[Egg_Head]

Lemforder or MB branded reservoir?

 

[GON]

Lemforder or MB branded reservoir?

Purchased the MB branded from the dealer, is Lemforder the OE?

 

[paulo57509]

Lexus puts filters in the reservoirs too. I've never had issues. However, I wouldn't know how to tell when they start to plug up.

 

[Egg_Head]

Purchased the MB branded from the dealer, is Lemforder the OE?

It is for W210, W212 and R230 models.