How best to replace power steering fluid in W202?

[charlysays]

My W202 has just gone over 200,000 miles. As such I thought it was high time I changed the PSF as this is the only serviceable thing I haven't done (I've even dismantled and repacked the front hub grease). The steering box also isn't worn out surprisingly despite the mileage, steering still feels precise even at high speed so I'm keen to keep it that way for as long as possible.
I think I've found the correct fluid - Febi 08972. Mercedessource on youtube has warned against using ATF as he has found it causes increased wear in the steering box due to lack of the correct additivies.
Can anyone please describe the best procedure for changing it?
Sucking as much old fluid from the reservoir as possible, topping up with new fluid then starting the engine briefly with the return line disconnected and in a bucket seems like a good idea but I'm worried about running the system dry if only for a few seconds. Or should I just do the lazy way and use a turkey baster to do repeated partial changes at the reservoir?
Thanks in advance

 

[Oldspanners]

On my W203 I used a large syringe to suck out as much as I could from the reservoir, topped up moved the steering from lock to lock several times (don't think I'd the engine running) and repeated until the fluid was the same colour as the new.

 

[charlysays]

On my W203 I used a large syringe to suck out as much as I could from the reservoir, topped up moved the steering from lock to lock several times (don't think I'd the engine running) and repeated until the fluid was the same colour as the new.

Thanks pal, Thats what Im leaning towards. Got a large turkey baster and have ordered two litres of yellow febi 08971 PAS fluid.

 

[Wighty]

Thanks pal, Thats what Im leaning towards. Got a large turkey baster and have ordered two litres of yellow febi 08971 PAS fluid.

When you look at some of the YouTube vids , there is another method of disconnecting the return pipe to the reservoir , adding an extension to it so it goes into a container .
Then turning the steering and topping up the reservoir as you go (making sure you have plugged the exit hole in the reservoir first )
I‘m yet to try this method though

 

[charlysays]

When you look at some of the YouTube vids , there is another method of disconnecting the return pipe to the reservoir , adding an extension to it so it goes into a container .
Then turning the steering and topping up the reservoir as you go (making sure you have plugged the exit hole in the reservoir first )
I‘m yet to try this method though

That sounds like the best way as it should wash through any grot and metal etc whereas the turkey baster method is going to leave a lot more contaminants sitting in there. Question is, will any damage occur if it runs dry for a second or two? That's my worry. My instinct says no as there will always be a film of oil on the pump bearings etc.

 

[Wighty]

That sounds like the best way as it should wash through any grot and metal etc whereas the turkey baster method is going to leave a lot more contaminants sitting in there. Question is, will any damage occur if it runs dry for a second or two? That's my worry. My instinct says no as there will always be a film of oil on the pump bearings etc.

I can’t answer the correct way buddy , it’s just YouTube stuff I’ve seen . If you figure it out take pics so I can do it

 

[mioba]

Suck as most out as you can. Refill.
Turn on car. lock to lock a good few times.

Repeat above 3 times.

And no letting it run dry for a second is not a good idea. Have you tried that on your engine )

I have also done the removal of the return hose method but that needs two people, as you need one to turn lock to lock and one to keep an eye on the reservoir (topping up). You also need to fabricate a pipe to fit on the hose to your waste.

In both cases the old fluid was surprisingly dirty and the steering much lighter on completion. Also in both cases its good to take the reservoir off and give it a good clean. The film sticks to the inside of the reservoir and that seems to hold the dirt

 

[charlysays]

Suck as most out as you can. Refill.
Turn on car. lock to lock a good few times.

Repeat above 3 times.

And no letting it run dry for a second is not a good idea. Have you tried that on your engine )

I have also done the removal of the return hose method but that needs two people, as you need one to turn lock to lock and one to keep an eye on the reservoir (topping up). You also need to fabricate a pipe to fit on the hose to your waste.

In both cases the old fluid was surprisingly dirty and the steering much lighter on completion. Also in both cases its good to take the reservoir off and give it a good clean. The film sticks to the inside of the reservoir and that seems to hold the dirt

I'll do this, thanks for the detailed info!

I've never run an engine dry no, but IIRC power steering systems don't have soft white metal bearings which could easily pick up with lack of oil pressure like an engine does. I'd rather not risk it nonetheless so I'll be doing it the way you describe

 

[Wighty]

I’ve bought a clear tube and some adapters , I’m psyching myself up to do the disconnect return tube method

 

[Oldspanners]

I’ve bought a clear tube and some adapters , I’m psyching myself up to do the disconnect return tube method

I don't think it would be worth it unless the car has done very high mileage without ever having the fluid changed as you'll never get the last residue out without completely stripping the system. If you really have a particular problem just use the suction method frequently over a period of several days.

 

[mioba]

I’ve bought a clear tube and some adapters , I’m psyching myself up to do the disconnect return tube method

Goooo Wighty.

Be sure to get the reservoir out and clean it.
There will be a film of dirty fluid in the inside that wont just flow.

 

[Wighty]

Goooo Wighty.

Be sure to get the reservoir out and clean it.
There will be a film of dirty fluid in the inside that wont just flow.

I’m now thinking eeek

 

[RhodieBill]

On my W203 I used a large syringe to suck out as much as I could from the reservoir, topped up moved the steering from lock to lock several times (don't think I'd the engine running) and repeated until the fluid was the same colour as the new.

That's what I've done on a few of my Mercs.... Seems to do the job.

 

[Wighty]

Had a quick look under the bonnet at the power steering fluid on each car , they both seemed to have a yellowish fluid , but the stuff I have to replace it is green ? Does the green fluid lose its colouring when old and go yellow ?

 

[mioba]

Did you take some out with a syringe and put it on a tissue. The colour in the reservoir can be deceiving.
Compare then with a drop of new on the same
tissue.

Where did you get the fluid from.?

 

[Wighty]

Did you take some out with a syringe and put it on a tissue. The colour in the reservoir can be deceiving.
Compare then with a drop of new on the same
tissue.

Where did you get the fluid from.?

Yes checked it on a tissue , maybe it yellows with age ? The new bottle of green stuff is Febi , I still have an MB bottle of power steering fluid which is green as well
Its Febi 21647 , MB 345.0 green (checked on opieoils site )

 

[mioba]

hmmmm, I am no fluid expert apart from the alcoholic beverage types.

So I wouldnt want to hazard a guess at the miscibility of the two fluids, Any chance of getting the MB fluid and checking the colour.

I am not sure about yellowing with age, they do certainly dirty with age (become darker).

If the fluid you have is correct, best way then would be to remove the return and get every last drop out, but I see your eek comment post 12.

I replaced the fluid green for green, the old fluid was dirty green, so yellowing no. That was also on a ford mind....

Be brave......

 

[RhodieBill]

Yes checked it on a tissue , maybe it yellows with age ? The new bottle of green stuff is Febi , I still have an MB bottle of power steering fluid which is green as well
Its Febi 21647 , MB 345.0 green (checked on opieoils site )

Febi 21647 is the correct choice for the w211 and w209 - your models. (And others like the W220, 212, 203, 204 ect.
Whereas the W208 uses Febi 08972 for some strange reason..... And is a lot cheaper! Oh, and is a yellow/brownish colour.

 

[mioba]

Just had a thought from when I done this on a ford, some cars use ATF for the power steering, other power steering fluid. Could this be the reason.