Steering Centralisation

[WGB]

The 116 has the steering that Mercedes was quite (positively) famous for feel and precision before rack and pinion arrived and changed the expectations.

All RHD Mercedes Benzes for decades have a tendancy to run down the camber of the road and pull a tiny little bit to the left - this was apparently a factory designed safety feature in case the driver lost conciousness and to try to prevent a head-on collision.

When I rebuilt my front suspension earlier this year I had a wheel alignment but forgot to centralise the steering before it was done .

When the car came back the wheel was at 6 o'clock (easily fixed) and the car pulled a little more to the left than I liked and lacked that certain something in the centre position that said - Mercedes Benz.

So today I centralised the steering

1) Get an M8x1.0 bolt - mine was a 35 mm long variety but length is not important - and grind the end into a point.



2) Jack up the car and remove the plug from the bottom of the steering box. With the wheels left on and the ignition lock not engaged it is easy to turn the steering and either looking up from underneath (where you will get covered by escaping oil at certain parts of the turn when the hydraulics are presumably open to the pump) or more discretely using a small screwdriver you will feel (or see) the central point arrive in the bottom of the hole.

3) I screwed in the now pointy bolt and being careful not to overtighten it I locked the steering in the central position.



4) At this point my steering wheel was only 1 spline out



So I removed the wheel and adjusted this



5) Then I checked where the wheels were pointing

Here is the left wheel which is pointing a little to the left



Here is the right wheel which is pointing a little to the left as well - suprise surprise.



I have done a rough and ready wheel alignment using my homemade wheel aligner so that the wheels are now pointing straight at the central position and will get a full alignment done through the week.

I believe that even this amount of subtle "off centre" is sufficient that I could have been fighting the power steering hydraulics a little while trying to drive straight ahead.

I will see if I have made any difference later in the week but would appreciate comments from Styria or anyone technical.

Bil

 

[SEL_69L]

Having been involved in road design in years past, I can say that as designer, you may appreciate that all well constructed road surfaces must have crossfall to allow for sheet water surface flow drainage. The standard minimum crossfall for a concrete pavement is 1% ( 1 in 100) for an asphaltic concrete pavement it is 2% (1 in 50), for a prime and chip seal it is 2 1/2% to 3 1/2% (1 in 40 to 1 in 30) and for well maintained unsealed road 4% (1 in 25)

With properly centralised steering there will, to a greater or lesser extent, be a natural tendency for any car to drift off to the left.

The opposite applies in countries where you drive on the right hand side of the road.

 

[Styria]

Hi WGB, you and I, both, have undertaken some corrective work on our steering boxes/alignment/cum whatever. You know what I am talking about.
In your case, it was a matter of centralizing the steering box by means of your centralizing bolt, and this showed both of your front wheels pointing to the left with the coupling on the spline being one spline out. Easy to fix, as you said, but will you not need to adjust your toe in/toe out connecting links ? If, as you say, the wheels pointed to the left, you would not have been able to drive your car if the box had remained in the central position. Thus, has this toe in/out adjustment yet been carried out ?

Okay, now to my situation with Gleaming Beauty. Quite frankly, I could kick myself because I did not get things right despite the fact that I knew what was required and how things should have been done. In my situation, with the steering box in the centralized position, my wheels according to eye assessment, were in fact pointing in the straight ahead position. That part was spot on, but even though I spent A LOT of time in fitting a new coupling to the splined steering box shaft, I did not gewt that position anywhere within cooee of being in the correct position. Accordingly, when I fitted the column shaft to the coupling, the steering wheel was half a turn out. I immediately suspected that I would have some problems with the blinker self cancelling feature, and that is precisely how it turned out to be. You know, it's okay, but not really right.

Presently, I don't feel like fixing the problem. The new coupling is a really tight fit on the steering box spline and I am not so sure if I could remove and re-position the coupling without removing the box from the car first. I guess, the tight fit is my only real issue, and I might yet attend to this task in due course. I am also a little concerned that refitting onto the spline could be a somewhat tricky job - it's easy to damage the spline once some sort of force was to be applied.

Driving the car, and steering stability, seemi to be quite satisfactory. The car is fairly positive in maintaining a straight ahead course when on the move, and it is only the action of the blinkers that leave a little to be desired.

Speaking of Mercedes Benzes following the left hand camber, one of my customers had an ML55 AMG, and it was chewing front tyres like you would not believe, and as well it was following the left hand camber of the roadway. Innumerable trips to the dealership failed to cure the problem - it was a design feature ! The car lasted six months - he couldn't move it quick enough. He now drives a hugely violent Holden Utility (power wise) and a Mitsubishi EVO.

Anyway, if you have any further thoughts on this matter, I would appreciate your input. Regards Styria

 

[WGB]

I never touched the coupling - I moved the steering wheel one spline to centralise it.

I did a DIY wheel alignment with some gear I made up years ago and straightened the wheels in respect of the steering.

I then took the car for a drive and it was totally different - responsive and the wheel was alive in my hand - so much so that I think I will shout it a new steering shock absorber - and the car tracked much truer.

It is booked for a full alignment on Wednesday and this time I will give them a reprint of the 116036 specifications.

In respect of the 164 ML series the front end is adjusted by replacing pins in the front suspension - there is no screw adjustment - it must be measured and then the correct pin with the correct offset purchased and fitted. It is considered a Dealer only adjustment.

Both my ML's track reasonably true but my ML 500 does wear the outside edge of the front left tyre slightly. I have had the geometry checked and it is within specs but I rotate the front and rear tyre a little more often to make them last. Those 19 inch alloys are sure heavy to change but the first set of tyres (Bridgestones) lasted over 40,000 km while my wife's ML320 continentals look unlikely to last that long.

I am running a set of Bridgestone run flats on my ML 500 now (as used on BMW X5) and althoiugh a little more bump thump they seem a very good tyre.

Bill

 

[Styria]

Hi WGB, I take it that you adjusted the front wheels yourself ? In other words, I take it that you achieved the "straight ahead" position yourself by adjusting the toein/out links yourself ?

How did you get on with the wheel alignment ? You know my slight problem - operation of the self concelling blinker arrangement. Mind you, on the other hand however, Gleaming Beauty is tracking quite straight and true without having to keep my hands on the steering wheel.

 

[WGB]

Hi WGB, I take it that you adjusted the front wheels yourself ? In other words, I take it that you achieved the "straight ahead" position yourself by adjusting the toein/out links yourself ?

How did you get on with the wheel alignment ? You know my slight problem - operation of the self concelling blinker arrangement. Mind you, on the other hand however, Gleaming Beauty is tracking quite straight and true without having to keep my hands on the steering wheel.

The car drove very well after my DIY wheel alignment and I had the wheel alignment performed professionally during the week.

I gave them the 6.9 specs and they managed to nearly achieve it all.

Now my wheels are "officially" aligned and the feel is not too bad but not quite as good as when I did it myself.

If I try again (unlikely) I will get them to align the car with the bolt in position.

I have now after all the work I have done cured my initial major problem when I purchased the car of a difference in feel with the car thrown into a left hand corner being very skittish and yet happy to go around a right hand corner at any reasonable speed stably and securely.

It is now the same in both left and right corners and I still haven't replaced the rear diagonal arm bushes or the steering damper (both to be done).

Bill