Power steering stutter...reservoir flush or replace during PS fluid flush?

[MechEngine]

I have a 2011 Mercedes GLK350 with poor maintenance history and have a slight stutter in the steering when turning the wheel quickly at the extremes stopped or at low speed. I plan on flushing. I noticed that replacement reservoirs are very cheap and believe they have an internal filter screen. Any advice on whether I should just flush, replace pump, or replace reservoir? I did check the existing fluid level and it was visible at the bottom 1/8"-1/4" of the cap/dipstick.

 

[JavierH19]

Likely just bad fluid but I believe there's also a sensor which commands a bit more engine power when there's enough use but not all cars have one but I imagine a modern Mercedes does. I don't think a pump replacement is necessary but if there is an internal screen that can't be cleaned easily and it doesn't cost much to replace then just replace the whole thing.

 

[JeffKeryk]

I like to remove reservoir and brake clean it out.

 

[LazyDog]

Check FCP Euro, I think they have a fluid additive for the power steering

 

[MechEngine]

I like to remove reservoir and brake clean it out.

AutoHausAZ had the oem reservoir, clip and seal for $38 and change... At least I'll know there aren't any dead mice or bugs in there...The fluid is $24 a quart...It will be a fresh start. Thank you!

 

[MechEngine]

Check FCP Euro, I think they have a fluid additive for the power steering

I saw that...I could not find lots of info on it...I think it is called "Lubrizol" ~$13 I will keep that in mind.

 

[jtwrace]

Clean out and flush usually solves the issue. I also like to add Lubegard to it too. https://lubegard.com/automotive/#submenu6

 

[JeffKeryk]

AutoHausAZ had the oem reservoir, clip and seal for $38 and change... At least I'll know there aren't any dead mice or bugs in there...The fluid is $24 a quart...It will be a fresh start. Thank you!

Sounds good. Dare I say a can of BrakeKleen is $3? Just sayin'...

 

[MechEngine]

Sounds good. Dare I say a can of BrakeKleen is $3? Just sayin'...

I would do that if the reservoir was $100, I'll gladly pay $17.54 for an OEM Mercedes part with a virgin filter screen. Since I'm typing...I am using Pentosin CHF 11S on the 2011 GLK350 is that the right stuff for the power steering?

 

[JeffKeryk]

I would do that if the reservoir was $100, I'll gladly pay $17.54 for an OEM Mercedes part with a virgin filter screen. Since I'm typing...I am using Pentosin CHF 11S on the 2011 GLK350 is that the right stuff for the power steering?

I would ask someone like @JHZR2 or @Astro14 about the MBZ line of cars. Maybe @edyvw ?

 

[Astro14]

It depends on the model. My SL has the filter integrated into the reservoir, the S has a separate, replaceable filter.

CHF-11s is the fluid on mine. I don’t think there’s been much change. Folks charged an outrageous price for that stuff, the cheapest I found is either Amazon or rock auto.

 

[edyvw]

Not sure whether MB sticks strictly to CHF-11s. BMW does that or ATF. i would check vehicle selector on www.fcpeuro.com or www.ecstuning.com. See what they recommend than find cheapest.

 

[kschachn]

Not sure whether MB sticks strictly to CHF-11s. BMW does that or ATF. i would check vehicle selector on www.fcpeuro.com or www.ecstuning.com. See what they recommend than find cheapest.

My BMW did not, they produced the same model in the same year with a label for either CHF 11 or ATF. Mine was the CHF 11.

And the label was on the reservoir cap where it could fall off. There was no other indicator on the vehicle whatsoever.

 

[gogydm]

Given that you have an X204 chassis GLK, here is the Mercedes official information on fluids you need to use when it pertains to the power steering. As others have said you need CHF-11 S.

 

[Marcozi]

If the ps system can use ATF, I would do a ps system flush. I did this several times on my old E46 bimmer. Basically, you remove the return line from the reservoir and extend the line to a large container. The reservoir return nipple has to be plugged. remove the existing ps fluid from the reservoir. Open and have a hand bottles of the new ps fluid. Fill the reservoir. I had 6 bottles of Dexron3 at hand and 2 bottle2 of Redline D4ATF. Start the engine and start pouring. It won't take more than a minute or so to go through the fluid!!!

 

[MechEngine]

Adventures in Power Steering! I completed the Power Steering reservoir replacement and power steering flush today on my 2011 Mercedes GLK350!
This is my story...
Accessing the Clip holding the Power steering reservoir to the PS pump is impossible! I drained the reservoir with a baster, removed all 3 bolts and intentionally broke the reservoir from the pump. Then the clip can be removed. I disconnected the return line from the old pump and put it into a dirty fluid catch bottle. I installed my replacement reservoir and new sealing gasket with a clip that I had modified with a pull ring out of safety wire for the next guy. I jacked the front wheels off the ground and cycled the steering wheel (engine off) till I poured the second liter of Pentosin CHF 11s into the tank. The fluid ran mostly clear green at that point. I made sure that the tank was pretty full, reconnected the return line and started her up. I made 20 complete cycles of left to right, dropped it and checked the fluid level. The system sounded great and did not stutter as before. I did get a goofy rash! I do not usually get rashes, so I suspect the hot pentosin CHF 11s when I was adjusting the final level. My recommendation is to always buy a new reservoir. They are relatively cheap ~$18 Autohausaz.

PS my return hose had a single use crimp hose clamp. I had to break that off and use a spring style hose clamp. Do not use a screw band hose clamp as you my break the plastic barbed fitting. The replacement reservoir came with a return plug that was useful to plug the return while flushing.

I am glad I was not in a rush...