Steering problem

[Sean2e0saf]

Wonder if anyone can help...

2007 w204 when driving at motorway speeds the steering is very touchy and seems light... other cars i have owned the steering stiffened up at higher speeds.... is this normal or a fault..

Thanks all

 

[Sean2e0saf]

Anyone have any info

 

[grober]

I am going to hazard a guess that its something to do with your car's front suspension caster angle.
Mercedes tend to run a greater positive caster angle than usual which gives them a strong self centering effect which conveys a feeling of stability at speed. I would suggest that a suspension alignment /check may help.

Positive caster angle
The pivot points of the steering are angled such that a line drawn through them intersects the road surface slightly ahead of the contact patch of the tyre on the pavement. The purpose of this is to provide a degree of self-centring for the steering — the wheel casters around in order to trail behind the axis of steering. This makes a car easier to drive and improves its directional stability (reducing its tendency to wander). Excessive caster angle will make the steering heavier and less responsive, although in racing large caster angles are used for improving camber gain in cornering. Caster angles over 7 degrees with radial tyres are common. Power steering is usually necessary to overcome the jacking effect from the high caster angle.

 

[Sean2e0saf]

someone mentioned to me about speed sensitive steering how would i know if this is working ok or not... i also have a lock to lock whine its not excessive i would say but is noticeable
i have thought about replacing the rack for a recon part

 

[grober]

Have you checked your power steering fluid level?

 

[Stratman]

It could be worn or incorrectly inflated tyres, worn damper(s) or as suggested above, worn or damaged suspension components.

Many years ago I had to take a moderately heavy device (microwave transmitter head) to be repaired. I put it in the boot of a pool car (Morris Marina), started the journey and had to pull over after a couple of miles because the steering was extremely light and the car was all over the road. After a bit of thought I removed the transmitter from the boot and put it on the floor behind the front seats instead, problem solved.

I mention this because it illustrates that a problem manifesting itself as a steering fault doesn't necessarily mean a steering component is faulty.

 

[Sean2e0saf]

Have you checked your power steering fluid level?

Yes grober i have... my 220 does not have speed sensitive steering so i found out today... however i have just bought a reworked rack for it so we will see if its any better next week when thats fitted..!

 

[PobodY]

I thought the speed-sensitive steering went the other way; it tightened at speed and gives more assistance when parking at low speed. - If it's not changing, maybe that's where the fault lies?

I found the steering in the CLK a little odd after the Nissan; not as much feed-back when meant that I initially didn't trust the turn-in, but I'm used to it now and have more confidence in it.

 

[Sean2e0saf]

I thought the speed-sensitive steering went the other way; it tightened at speed and gives more assistance when parking at low speed. - If it's not changing, maybe that's where the fault lies?

I found the steering in the CLK a little odd after the Nissan; not as much feed-back when meant that I initially didn't trust the turn-in, but I'm used to it now and have more confidence in it.

It does work that way.. thats what i was saying my steering at motorway speeds is very light and a bit twitchy..

But i found out today my c220 does not have speed sensitive steering...

 

[Yugguy]

Are you sure it doesn't? I thought all w204s did.

 

[markjay]

Are you sure it doesn't? I thought all w204s did.

Just to say that not all W204s have the same steering rack, the C180 with the 1.6L M274 engine has electric power steering (not hydraulic), and might behave differently to the conventional steering rack.

 

[markjay]

But more to the OP's point.... light steering could be a characteristic of the car, but as others already said above there are very many other parameters that could affect this, from the condition of the suspension and steering rack, through the tyres' make/model/condition/pressures, and obviously suspension geometry.

 

[markjay]

Also, I found that with Dunlop FastResponse and BluResponse tyres, the steering felt much more 'nervous' compared to ContiPremiumContact 2. Which is fine as this is what Dunlop are actually claiming - but it does show how tyres can alter the steering.

 

[190]

Another variable on W204's is that the earlier Blue Efficiency models while still hydraulic assisted, have a clutch that disengages assistance in the straight ahead position. For me the transition isn't detecatable but I wonder if the steering would feel very light if for some reason assistance wasn't disengaged .

 

[Sean2e0saf]

ok here goes

firstly the car 100% does not have speed sensitive steering option confirmed with mercedes technical support

tyres are uniroyal rainsport 3 all round

and finally mine is a standard 220 170bhp not a blue efficiency model

now im not sure as yet of the geometry however it is getting a new rack and new febi track rod ends on friday..!

then im going to get the cars tracking redone with a hunter machine..