W211 steering stiff - ongoing saga

[selphy]

Hi all,
For a long time now I've been trying to diagnose a problem with stiff steering on my 2008 W211. It's fairly stiff at all road and engine speeds and it doesn't return to the centre very well after a turn. Things I've tried:

• Tyre pressures OK.
• Upper and lower balljoints and track rod ends replaced with original parts.
• Upper strut mounts replaced (this cured a gentle knocking noise in warm weather on undulating roads).
• Wheel alignment set-up with Hunter equipment. Castor is at the upper limit, camber and toe are almost exactly in the middle of the spec. Tyre wear is very even.
  
• Power steering fluid changed and it's perfectly clean.
• Aux drive belt, alternator free wheel pulley and tensioners all changed.
• Attempted to clean mesh strainer in power steering fluid reservoir with solvent and gently blowing with air to thoroughly dry, seems OK and not blocked.

With the front wheels off the ground the steering feels reasonably light with the engine running but it's not as light as I would have expected and you still need to use a bit of force to turn the wheel. With the track rod ends disconnected it's a bit easier.

With the front wheels off the ground and the engine not running it's really quite difficult to turn the steering wheel and the stiffness is not uniform from lock to lock. After cleaning the PS pump reservoir strainer I had to bleed the air from the system by turning slowly lock to lock multiple times and it was hard work (with wheels off the ground). I've tried the same thing on a Ford with hydraulic power steering and it was really easy to turn the steering wheel with the engine off and the front wheels off the ground - makes me think there's something wrong with either the steering linkage universal joints or the rack itself. Any suggestions?

Thanks

 

[whitenemesis]

Does it have Parametric power steering? Perhaps get the codes read?

 

[Nicebutdim]

There's a good explanation here of speed sensitive power steering and the faults that can occur

Mercedes-Benz Speed Sensitive Steering - The Rundown

 

[selphy]

There's a good explanation here of speed sensitive power steering and the faults that can occur

Mercedes-Benz Speed Sensitive Steering - The Rundown

It's an E220CDi Avantgarde and it doesn't have speed sensitive or parameter steering.

 

[OneForTheRoad]

nearly all mercs have speed sensitive steering. yours being 1 of them .

see if you have number 300 in this picture.


STEERING GEAR MERCEDES E-KLASSE [Car] [CHASSIS] (EUROPA)

 

[selphy]

Thanks, I'll check the steering rack later but I'm almost certain it doesn't have any sensors or actuators on it at all. I don't have code 213 on my data card either:

205B OWNERS MANUAL AND SERVICE RECORD - ENGLISH
249 INSIDE AND OUTSIDE MIRROR AUTOMATIC DIMMING
255B MB MOBILO WITH DSB AND GGD
280 LEATHER STEERING WHEEL AND LEATHER GEAR SHIFT KNOB
283B AIRBAGLABLE - ENGLISH
287 THROUGH-LOADING FEATURE
335B INSTRUMENT CLUSTER LANGUAGE - BRITISH ENGLISH
423 5-SPEED AUTOMATIC TRANSMISSION
461 INSTRUMENT WITH MILES IND. AND ENGLISH LEGEND
477 TIRE PRESSURE LOSS WARNER
500 OUTSIDE REAR VIEW MIRROR LH AND RH FOLDING
523 RADIO AUDIO 20
537L GREAT BRITAIN AND NORTHERN IRELAND
543 SUN VISOR WITH MAKE-UP MIRROR L. AND R., BE-
551 ANTI-THEFT/ANTI-BREAK-IN WARNING SYSTEM
573 CHILD SEAT MOUNTING, ISOFIX IN REAR
580 AIR CONDITIONER
5XXL EUROPE
600 HEADLAMPS - CLEANING EQUIPMENT
618 BI-XENON HEADLAMPS FOR LEFT-HAND TRAFFIC
619 CORNERING ILLUMINATION
666 PRODUCT PROT.F.TRANSPORT VEH. W/O TIE-DOWN HOOKS
673 HIGH-CAPACITY BATTERY
677 AVANTGARDE/STANDARD SUSPENSION
690 EMERGENCY SPARE TIRE (MINI SPARE)
732 WOOD VERSION,BIRD'S EYE MAPLE BLACK/ANTHRACITE
740A FABRIC, AVANTGARDE
741A FABRIC, AVANTGARDE - BLACK / ANTHRACITE
775U BRIGHT SILVER METALLIC CLEAR COAT PAINT
809 AEJ 08/1
817 HOUSING FOR ALARM SIREN (ATA)
875 HEATED SCREEN WASH SYSTEM
882 INTERIOR SAFEGUARD
910 DYNAMO WITH HIGHER CAPACITY (FFO)
926 EXHAUST GAS CLEANING WITH EURO 4 TECHNOLOGY
954 EQUIPMENT PACKAGE FOR AVANTGARDE VEHICLES
983 COC PAPER EURO 4 TECHNOLOGY W/O REG. CERT. PART II
989 IDENTIFICATION LABEL UNDER WINDSHIELD
99N STEUERCODE WERK SINDELFINGEN/GRAZ
F211 SERIES PRODUCTION 211
FS COMBI - VEHICLE
GA AUTOMATIC TRANSMISSION
HA REAR AXLE
K11 ADAPTIVE STOP LIGHT FLASHING
K13 CONTROL CODE FOR SERVICE INTERVAL 25000 KM
M002 ENGINES WITH EXH.TURBOCHARGER WITH INTERCOOLER
M010 EVO/VEHICLE UPGRADE ENGINES
M22 DISPLACEMENT 2.2 LITER
M646 R4-DIESEL ENGINE OM646
R RIGHT-HAND STEERING
R01 SUMMER TIRES
R78 LA 16" 5 DOUBLE SPOKE DESIGN
U15 2ND CARGO AREA W/ COMPART. UNDER MAIN FLOOR PANEL
U16 STOWAGE TANK BEHIND REAR SEAT BACKREST
U18 AUTOMATIC CHILD SEAT RECOGNITATION (AKSE)
V06 SPEED- + LOADINDEX 95W
VL FRONT AXLE HALF, LEFT
VR FRONT AXLE HALF, RIGHT

Mercedes Benz VIN decoded at Mercedes-Benz VIN Decoder

 

[willg]

I've got a 2006 e220 cdi facelift I can try jacking it up to see how easy the steering is to turn if that would be helpful. Not until later in the week or weekend though.

 

[selphy]

thanks willg - that would be really useful.

 

[Azeem]

I am having the same issue on mine. My issue came up when the mechanic put the wrong PS fluid in my car which was flushed and we put in CHF11S. The steering was slightly better after that. After six months or so I flushed the PS fluid again last month but it is not any better. I was suspecting PS pump but it is not making any noises when I turn the wheel from lock to lock. I am inclined to think it could be PS rack that is the culprit. Have you checked yours?

 

[selphy]

If your mechanic only topped the system up with the wrong fluid I doubt it would cause your problem. If he needed to top up the fluid then maybe there was (or still is) a leak - have you checked inside the bellows on your steering rack tie rod ends for a fluid leak?

I think if your pump is failing you would tend to have heavy steering at low engine speed and it would get better as you rev the engine.

One thing I did find when I took my pump off was that there is a fine mesh screen non-replaceable filter in the bottom of the fluid reservoir which prevents particles entering the pump. There's not really any way to clean this filter- I tried with some solvent and an air line but I'm not certain how effective it was. If it's blocked the suction side of the pump would be starved of fluid and you could get a problem. Taking your pump off is a fairly easy job if you're a competent DIYer. Once the pump is off you can detach the reservoir and have a proper look at it.

 

[selphy]

Azeem, Surely your E270Cdi does have speed sensitive or parameter steering. You should check your data card for code 213. If you have this option get your codes read on Star.

 

[Azeem]

It doesn't have Speed sensitive steering for sure but you have got me thinking on reservoir bottle though. While doing some mechanical work on manifold the mechanic broke the line to the PS reservoir. They changed the PS reservoir bottle with an old Part and filled it with non CHF11s fluid (I think they put Febi oil in it). When I got the car back the steering was very stiff. I asked them to flush it and put CHF11s in. The steering got slightly better but it was still stiff. I always thought that my PS pump has gone bad but I never thought of changing the PS reservoir. You reckon I should try changing the PS reservoir as the mesh may be blocked and pump is having difficulty getting the fluid?

 

[selphy]

Well it is possible that the power steering reservoir strainer is blocked and the pump is being starved of fluid on your car. It might even be the problem on my car - I wasn't really sure if I had cleaned it properly because the mesh screen filter is only just visible through the outlet pipe and it is inside the reservoir itself - obviously it's not a serviceable part. By the way, Febi do make a CHF11s compatible fluid so your mechanic might not have used an incorrect fluid - the Febi stuff looks a bit thinner than the original MB stuff though - I've tried both!

It might be territory specific but I thought that all the 6 cylinder engined W211s did have speed sensitive or parameter steering. Have you looked at your steering rack for electrical connections?

 

[HITECH]

This might stupid but it happened to me few weeks ago when I was getting a engine block freeze plug replaced. Had to remove front exhaust, cat, etc etc. Anyway, there is a heatshield just above the top steering knuckle that surrouds it. When the job was finished my steering was slightly heavier and a slight harsh feel to it when turning into a left hand road. I jacked it up and checked it out. It was that heatshield that was against the steering knuckle. I simply bent it back into shape away from the knuckle and that was my problem solved. I doubt this will be yours but hey ho, never know. Just another suggestion to try and rule out bud.

 

[Azeem]

Selphy, mine is 5 cylinder and it doesn't have electrical connections going into the rack.
I am going to source a PS reservoir/bottle for peace of mind. Are you driving your car in C or S mode? Try driving your car in S mode and let us know if you feel any difference.

 

[selphy]

No, the C / S mode has nothing to do with the power steering at all. On my car, there is absolutely nothing electrical/electronic that affects the power steering. It's a hydraulic pump driven off the auxiliary drive belt, some hoses, pipes and a steering rack.

 

[Azeem]

Did you manage to resolve the issue you were having with power steering?

 

[Azeem]

Selphy, I changed the PS reservoir and put MB power steering oil to no effect.