6.9 potential disaster.

[WGB]

I am in the process of rebuilding my steering linkage and upper suspension arms/bushes and on re-fitting the idler arm (with a new kit) I noticed that when it was cycled to the position of left full lock it did not stop at the stop on the subframe but rested against the positive battery feed to the starter motor. The end connectors were a little distorted and displaced the cables away from the side of the engine by a couple of centimetres.

Neither the squared off area on the arm itself nor the riveted contact plate on the subframe appear ever to have contacted each other in the entire life of the car whereas the same on the opposite side show quite measurable wear on both the pitman arm area and it's respective plate. After connecting it all up again it still does not contact the stops on the left side.

I guess in a RHD car right lock is used a lot more than left and I assume my steering box is not at it's central position in relation to the Pitman Arm but the really scary thing is what would happen if the idler arm regularly contacted the battery cable and started a firworks show.

I corrected the shape of the connections and re-routed the cable so that if left full lock is ever required in the future the correct stops will come into play but I would suggest that you may want to check your own cars before the fireworks start.

Bill

 

[Mercules]

That is scary - but surprising, given the overall genius in design the rest of the car exhibits. Having seen what happens when a battery explodes (i had front row seats!) I would, agree this is sound advice to all owners.

 

[Styria]

Hi Bill,

the timing of your thread is absolutely uncanny. The way I read it, you have too much lock when turning the steering wheel to the left hand side. Am I understanding you correctly ?

My situation is exactly the opposite-I have too much lock to the right. As you know, I fitted new 18" Schnitzer Alloys to my 'Gleaming Beauty' but I have temporarily removed them as I needed new tyres, and I also wanted to have a wheel alignment carried out before re-fitting these wheels and the tyres. Anyway, that's all by the by. Prior to removing the 18"ers, I experienced what I thought was total lack of power steering assistance when negotiating a particular round-about near my home one morning-I had difficulty turning the steering wheel. So initially, I put this down to having a steering box or steering pump problem and really put the problem out of my mind to be 'fixed'at a later stage-as a rule, I am not one to hit the panic button.

In due course, I removed the right front wheel and to my consternation, discovered that the inside of the tyre had rubbed right back to the steel band. Preliminary examination revealed no real cause and, again I put it out of my mind, but I was somewhat puzzled and one day decided to slightly grind the edges of the body bracket that locates the rear of the lower suspension arm and fitted the standard 14" Bundts on a temporary basis.

When I had the car up in the air, and moving the wheels from side to side, I noticed that the right front wheel refused to turn when on full right lock. It was then that I discovered the tyre to be rubbing the side of the lower control arm. Initially I put this down to the fact that the car was jacked up, but lowering it back to normal load, there was still contact, even with the standard 14" wheel and tyre.

Now, there has to be a reason for this and my mind went back to when I had a very competent and experienced Mercedes mechanic change the steering box for me as I had other tasks that I wanted to attend to. It would appear that the box is not centralized as can be achieved by removing the bolt from under the steering box which exposes the locating hole. The way I see it, the only way to address the problem would be to at least partially remove the box (not sure if there is enough freedom of movement without disconnecting the coupling) and re-position the coupling and then perhaps re-position the steering wheel inside the car. Am interested in your opinion. Regards, Styria

 

[WGB]

There are several problems raised by this.
1. There is a potential danger from the steering contacting heavyweight unfused live wiring.
2. That my steering box is probably not centred - the major problem with this would be some possible unnecessary clearance in the steering wheel in the straight ahead position which does not seem to be a problem when driving this car.
3. My car has a set of wider than normal AMG wheels and tires and the left hand tire will contact the lower arm on left full lock now (THere is a shiny area in the arm but no tyre damage) but not so bad as to cause any noticeable wear. This means that I can't get any extra left sided lock anyway as the tire is the limiting factor.

My impression is that my steering functions pretty well any way and I don't know if I really want to start from scratch with the boxed locked at the central position and all adjustments starting from there.

Bill

 

[Des]

There are several problems raised by this.
2. That my steering box is probably not centred -
Bill

How would that occur?
Has someone had it out of the car in the past and not put it back in correctly?

 

[WGB]

Whether the box has been removed or not would not misalign the steering - I would assume that either the pitman arm has been removed and replaced one or two spilnes over from it's original position or else a whole lot of wheel alignments have beendone without anyone centreing the steering box with a pin - as Styria has suggested.
Bill

 

[Oversize]

This is an interesting topic and I'll endeavour to get some pics of Red Bull in the left and right lock positions... Despite all my suspension issues, at least the steering seems ok!

It sounds to me like many boxes have been removed where both the pitman arm and coupling haven't been suitably marked. The splines should be clearly marked with a centre punch as texta, paint, or liquid paper can all wash off during cleaning. With so many splines to choose from, it can prove a nightmare to get right again. I do need to rebuild at least one box and I might actually count the splines and the position of the attached components. This may help others in the future when they have no marks to guide them for re-assembly.

 

[Styria]

Hi Mark, the respective positions are already well marked by the manufacturer and there is no need to mark any part. The most contentious issue relates to the positioning of the coupling onto the splined shaft of the steering box. That can be a real hit and miss affair, and almost impossible to set up correctly. Unfortunately, the weight of the steering box, when refitting, does not really encourage one to pull it out again in an endeavour to obtain a more correct position. Of course, small adjustments should be possible by adjusting the tie rod ends, but there seems to be a reluctance on the part of wheel aligners to follow that procedure. In turn, of course, this affects the return action of the indicator lever. Regards Styria

 

[WGB]

I see we are resurrecting this old thread again.

I have since this date centred my steering with a bolt (twice) as well as checked the arm was centralised on the box and that all parts carry the correct 6.9 part numbers.

I have also had a wheel alignment done with teh box centralised.

My impression is that the steering stop positions probably work correctly for a 450 but that the 6.9 system ends up with slightly different geometry when at the end of it's travel on both sides.

My steering is now knowhere near able to contact the live connection on the starter motor after adjustment and my replacement rubber insulator still looks pristine and unmolested.

Bill