Is this regular scheduled maintenance or just a waste of money? My steering feels a bit loose but all the joints/bushings are fine. Any experiences?

Thanks

 

Have your front batt changed. If you have SBC, I found that to have helped quite significantly. Just my 2cents, also if I were you change all the hoses and rubber seals, etc, new MB oil and that's it. Have your steering rack checked, you all set for absolute pleasure again.

 

Also have your control arms checked, rubber bushes etc....

 

I would not be because you PS fluid is dirty. There isn't really any thing to contaminate the fluid. MB does not require changes. It is a waste of money.

 

The fluid does contaminate and brake down do the heat cycles from compressing the fluid. This will not affect the tightness of the steering at all. (neither will the aux battery). It may help prolong the life of the steering rack and pump, as the conditioners in the fluid help prevent failure of the seals. It may also help to reduce the whining noise of the power steering system.

MB does not have any required service interval for power steering fluid. Toyota does not have a required interval for brake fluid. That does not mean the fluid should never be renewed.....

But no, it will not fix a problem and should be purchased with the knowledge it is stictly preventaive maint only....

 

And I maintain that if you pay someone to flush all the old fluid out and refill you will never get a return on that investment. What change interval would be required to prevent seal failure and other problems, 30, 60 90K miles?

What contaminates the fluid? there is no combustion and I suspect very little wear metal.

 

Although you didn't mentioned it, am I to assume that you don't have a fluid leak? I only ask because MB has a TSB out on this (fluid leak from the rack).

Regards,
paul...

 

Nope, no fluid leak. I read that there was a service special for a flush and it said that the flush would 'return the sharpness of your steering'... I didn't believe it. I do have a very slight humming noise when turning at stop, but seems fine.

Thanks guys!

 

Hey guys I have an 09' E350 and wondered if the steering should be as "loose" feeling as it is on my car?
I had a w203 before my E350 and i must say the steering felt more sturdy and secure compared to my E class. Is this normal or am i missing something?
Flush needed maybe?
No fluid leak in pump area.
Thanks.

 

I believe in a flush. With today's vehicles with rack and pinion steering, the fluid takes a beating. Did you ever smell the fluid?
Just my $.02
Mike T.

 

Never smelled the fluid
just the feel of the steering is very loose

 

To maintain the correct power steering fluid level is very important. A few months ago when I backed out of the garage, I heard a squeaking noise, like the old fan belt noise. After warmed up it was OK. So I did not bother with it. About a few weeks later, the noise did not go away. Of course, I did not drive it and checked the power steering immediately and found it was low. Went to this forum and checked for the correct fluid to use. I think I only poured about a couple ounces to fill it.

So the correct level of the power steering fluid is important!

 

fluid does break down as it goes thru the heat cycles. Ask any mechanic. However, the recommended intervals by places like jiffy lube is a joke.

 

How many liters to do a flush in a w211?

 

The owners manual for MY06 says the PS has .9liters.

The fluid used is full synthetic Pentosin CHS 11S

 

The change is simple. used a syringe to drain the old and new is poured into the container. After 100 km repeat the procedure. Invest $ 10 now to save $ 1,000 after a while!

 

Reviving this older thread, the power steering "flush" is simple enough. You can go all out and drain from the rack and refill it but this is the next best thing.

I started with 2 liters of the Mercedes hydraulic oil (sad news it does not come in the blue metal tins anymore). You can use Pentosin, however the MB fluid does have additional conditioners in it so I always use MB fluid.

If you have access to a vacuum evacuation pump like the one in my photo, its easier. If not, just use a turkey baster or siphon it out with some aquarium air hose.

Now, pop the steering cap off and clean it. It's usually pretty gunky. Pump out all the fluid in the reservoir and refill. It takes about 1/3 liter every time you drain the reservoir. Fill and start the car turning the steering wheel from clock-to-clock as many times as you'd like (I did it 2x). Repeat the process 3 more times draining and refilling. On the 4th and final fill before you drain again, let the car idle for a few minutes to get the fluid to operating temp and really move the steering wheel. I do this to get every last little piece of gunk out of the system. Drain one final time and refill it.

As other members have stated these power steering systems really do beat up the fluid and you will get more out of your car if you take care of her. I notice a quieter pump every time I do this.

Side note! Pre-facelift cars have two different power steering pumps. If you have air suspension it uses the blue Mercedes hydraulic oil (Pentosin) if you have conventional suspension on your pre-facelift W211 the pump *should* use regular power steering oil/transmission oil. Post facelift vehicles should all use hydraulic oil. If you make a mistake, just flush it again. You can mix the hydraulic oil into a conventional power steering system and be OK, but not the other way around.

Hope this helps someone!

 

Maybe I missed it.. but did anyone mention replacing the reservoir?
I mention this as it has a filter in it, and WILL get dirty.. if the fluid is dirty..

So, if there is going to be any "flush" or "drain and fill", then maybe we need to think about replacing the reservoir at the same time as they aren't that expensive.

I am about to do just this on my 07 E63 Wagon, and the power steering is making some noise, and read that replacing the reservoir and fluid can help with this noise.

 

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