Wider than standard tyres on a 6.9 - problems

[WGB]

I finished my front suspension on the 6.9 today and one of the last things I discovered was a rub mark on the right front rubber hydraulic line.

I have always thought my 6.9 was harder to park than my 450SEL as the steering lock was not as tight. My car hits the steering stop when turned to the right but lock to the left is governed by the steering box and it would appear the steering has never hit the left hand stop in it's entire life.

The rear edge of the front left lower arm is shiny but I can see no wear on the tyre so it must be an infinitesmal rub. What is more of a worry is that the right front hydraulic line has a tyre wear mark on it.

I have temporarily put shielding over it to protect it and will replace the hose ASAP - as well I will have a talk to the people who will be doing the wheel alignment to see if they can equalise the box so that it is more even left to right but if it returns with the same problem I will be drilling the rivets out of the stop plate and fabricating some other arrangement.

First thoughts are removing the stop plate on the left hand side (Only needs two rivets drilled out) and Migging up an adjustable M10 or M12 bolt and trapped nut plus lock-nut arrangement so that an extended and adjustable stop will actually work.

My car is fitted with 225 section tyres on 16 inch AMG wheels so they are not exactly wild but the car does sit a little lower than standard ride height.

My suggestion is to not only check for a rub mark on the lower suspension arm rear surface but check what the front edge of the opposite tyre is getting up to at the same time - particularly in a 6.9 with hydraulic lines in this position.
Bill

 

[Styria]

Hi Bill, the position of the large hydraulic oil line attached to the top of the front strut is adjustable. I have reason to believe that you have removed the front struts and it could well be that when you refitted the top mount of the strut that it might be slightly out of position. Thought about that ?

Also, centralizing your steering box.I would think that it is almost impossible to centralize the box whilst still fitted to the inner guard - i.e. in situ. It's a bit of guesswork, with the box out of the car, when refitting the splined section of the coupling to the steering box shaft. Thus, get it close to where you think it should be, offer the box up temporarily and establish a fairly accurate relation between the two square sections and then check the position of your steering wheel to see its position as part of the overall operation.

The location of the pitman arm should not be the subject of confusion or guesswork. From what I recall, its correct position is clearly marked. If however your box is centralized, and if on full lock either way a standard tyre rubs against the side of the lower control arm, that could become a troublesome situation. In your case, with the larger rims and tyres fitted, that could well be the cause of your problem.

As an aside, it would be nice to have S-Class on board - his knowledge and experience are invaluable. I have heard from him and I think he has seen TOPKLASSE as a guest - not sure - I think he is a little confused as to what has transpired, plus he has his own well documented problems he has to attend to. Maybe a slight and gentle nudge could tip him over the right way ? My thoughts. Regards, Styria

 

[John S]

To ensure that the steering box is centralised isn't there a pin that fits into and locks the box in its central location? You then adjust the steering linkages etc from that locked position.

 

[WGB]

It is in today at the place I get all my alignments done and have told him the story - I will see what eventuates.

Bill

 

[Styria]

Hi Bill, the outcome will be of great interest. Also John, whilst I am familiar with the centralizing of the pin to lock the box in the central position, actually fitting the splined coupling in the correct position appears to me to be subject to a certain amount of guesswork. One could be a couple of splines out, but one still has to marry the square section of the coupling to the bottom of the steering column. One may well have to carry out the final correct positioning at the steering wheel end.

I am also thinking that if the front wheels are not pointing dead straight ahead with the pin in position, other adgustments may be necessary on the tie rod ends. Interesting - any further suggestions ? Regards, Styria

 

[John S]

I am also thinking that if the front wheels are not pointing dead straight ahead with the pin in position, other adgustments may be necessary on the tie rod ends. Interesting - any further suggestions ? Regards, Styria[/QUOTE]

Absolutely right Styria, once the steering box is locked and the steering arm is in position the tie rod ends may have to be adjusted by increasing one side and shortening the other. After 30 or so years of quick realignments the steeriing wheel may have to be moved to bring it into the correct straight ahead position.

 

[WGB]

It has been aligned and the guy said it appeared to be centralised with equal lock both sides.

The car now drives well and tracks beautifully and I don't really want to interfere with it at the present.

I will be replacing the Brake Fluid with genuine M-B Dot-4 soon so will see what things look like up on the hoist.

Bill

 

[Styria]

Hi Bill, thanks for that. So, is it correct to assume that your left front tyre no longer touches the side of the lower link ? If not, and whatever they did, it is good to know the problem is fixed. Regards, Styria

 

[Styria]

Hi Bill, I was just wondering if the work carried out by your Wheel Alignment people has fixed the tyre touching the outside of the lower link ? As you know, I have the same problem, but on the right hand side. Regards, Styria

 

[WGB]

I must say my car is driving and steering very well but I had a 116-free weekend so haven't looked underneath to see what is happening.

I placed plastic corrugated tubing over the rubber line and try not to use too much left lock but will have it up on the hoist changing brake fluid, putting thread-lock on the vacuum modulator and changing the diff oil as the next jobs and will see what is happening to the left arm and the right hose at the same time.

This is not going to happen for a few weeks as my son and I are flying out to New Zealand on Thursday for a week to stay with my parents. My mother has not been herself and it is her birthday next week so it is time for a rare trip home to my birthplace.

I'll let you know and probably post photos when I get around to the job.

My thoughts are that if the rubbing continues and I am happy with the centralisation I will probably fabricate adjustable buffer(s) where the plate(s) are rivetted to the subframe using heavy bolts and welded nuts.

Bill