We've been going to them for about 30 years now lol. I usually do all the work that I can and pass on annoying/special tool required jobs to them... They don't do alignments and stuff like that.

Well, if the road has a high crown, then it may try to fall off the crown, or go up the crown, but just a little. On most any interstate, it should go straight as they usually don't have high crowns.
On an interstate my 500 will go untouched for maybe 1/4 mile or more. My 300D on the other hand will put you in the ditch if you let go of it. It is only used for local travel so I haven't tried to fix it. I guess I should, but it doesn't wear the tires unevenly or anything so I just leave it alone.

The steering box has a place that is centered in its travel and should be at exactly that spot when going straight. That is what the alignment tool is for. If it is not adjusted to that spot, it will pull and or drive funny, for instance, it may be more sensitive when starting a left or right turn. I will see if I can find more information about this subject. Someone with a service manual should be able to look it up for us.

Paul

I just found this on another site. It explains about the locking bolt and centering the steering. I hope this works. You may have to copy and paste.
Steering wheel alignment/centering? - Benzworld.org - Mercedes-Benz Discussion Forum

This is about a different car but I am sure it is the same for the 126.

Paul

Well I rotated the tires on the 420SEL. I believe that took care of a large amount of the vibrations. I'll probably drive the car up to work sometime this week so I'll be able to tell more. These tires were directional so I could only go front - to - back. They had about 7500 miles on them since they were installed.

I will probably rotate the 300D's tires today as well and see what impact that has. I believe these tires are non-directional. So the "X" pattern will be used.

Edit: Looked at that link abit, thats interesting stuff. So when that bolt is installed to lock the box, all the fluid comes out? Hm. So as I understand it, in order to perform a proper alignment: 1) lock the box, 2) install spreader bar. 3) align. ?

No the oil only comes out if you turn the steering wheel full lock to the left.

http://www.peachparts.com/shopforum/2768406-post5.html

If you want information about DIY alignments here's how I did it

http://www.peachparts.com/shopforum/diesel-discussion/284337-how-i-adjusted-toe-out-camber-caster-my-w123-300d.html

I would not recommend cross rotating any radial tire.
The radial belts in a new tire, start off being "vertical". When the tire heats up during normal driving, the belts sort of creep a bit in one direction, then when they cool down, the rubber sets these belts in their new position...which is now not "vertical".
If you switch rotational direction on a radial, those same radial belts now have to creep back to vertical, then creep in the new direction.:eek:
This amount of movement within the tire can lead to the radial belts separating from the surrounding rubber holding the belt in place and can lead to bumps in the tread, or even having the entire tread separate. :(

These W126 respond very well to Michelin tires for some reason.:D

Just to update this thread..

The General Altimax HP's that are on the 420SEL are directional so they were rotated front to back.

The 300D had its tie rods and center drag link replaced. All were bad. I had it aligned at the dealership and they did an excellent job.

I had the 420SEL up at the dealership and they found that the replacement steering gearbox, that was 7 months old with 4,000 miles on it had gone bad. It was leaking and had excessive play. They quoted an MB replacement box around $3500. Luckily I had my local independent source the gearbox when it was installed 7 months ago so they can deal with it. When I had the box installed 7 months ago the first unit the received from their supplier leaked. So this is the second box. I'm not sure what brand the box is, they use WorldPac I believe.

At least MBNO had the wherewithal to inform me that the box was bad. My local dealer didn't. After 2 attempts at aligning it they just said it will always pull that way.

Alignment Spec Sheet
http://i.imgur.com/A6mPqdPl.png

Technician's Notes
http://i.imgur.com/4m1Fcial.png

Part from WorldPac
 

My experience has been that sometimes WorldPac sources OEM parts, other times aftermarket parts made by the manufacturer of the OEM part (such as you see listed on PP parts inventory), and sometimes they source xyz aftermarket parts.

As WorldPac is owned by Advance Auto Parts, who obviously sells a ton of aftermarket parts, and the fact you've gone 0 for 2 on the two previous steering gear boxes, I think I'd get to the bottom of who has manufactured this part. It sounds like it must be from xyz aftermarket manufacturer and they make a lousy steering gearbox. I'd make sure they don't put a 3rd box in from the same manufacturer. Just my 2 cents.

Who've obviously put your trust in the repair shop. They owe it to you to do a better job of communicating what parts they're using.

I'll be sure to ask them the brand tomorrow. My family has been doing business with them for 30 years, they've never violated that trust or doing anything shady. They said they'd take care of the gearbox, no problem.

In my searches I've only seen two brands listed online. Maval and C&M Hydraulic. I've got a Maval box that I sourced and my shop installed currently in my 190E (almost 2 years now) without any problems.

I'll be sure to find out and report back though.

Boy diagnosing something over a forum is not the most scientific, but if I HAD to pick something I would say you have a tire/wheel balance issue causing the vibration and an alignment issue causing the pulling.

Looking at the numbers on the sheet and comparing the starting values the adjusted values and the target values I get really irritated by adjustments that were made that end up not being within the target values...

...looking at the comments on the second sheet it seems like the mechanic gave up. It seems like he's had a look at the car decided that he doesn't like the rust - hasn't made a fuss about the vehicle not being level and then put it on the machine.

Interesting to see the measured toe with and with out the spreader bar though.

Which values are you referring to that were out of spec?

What made you come to that conclusion?

Not being level?

The service adviser commented that he tried to adjust the box as much as he could, he didn't want to break it and render the car unusable. The box is indeed sloppy. Saturday I checked the pump reservoir and saw that it was low. The fluid was clean and clear. I could easily see the filter. I added a few ounces of clear power steering fluid. I checked back a day or so later and it turned to a brown mud color. :O

Track difference angle although it doesn't show up as red text as well as the other red text at the end seem to be problems to me - the whole car not being level section isn't filled in...

...the comments made seem to suggest a lack of patience with the vehicle to my mind. You know - oh it is old...

Hmm you're right about the tracking difference angle. It doesn't show up as red, odd. Not sure what to make of the level section not being filled in. I do wonder why it was not.

The tech came highly recommended to me. I've not been disappointed in his work with my 300D.

I'm not sure I can draw the same conclusion about the comments. They just seem brief and to the point. I mean something is definitely wrong with the gearbox, it just turned clear fluid into mud in a day. I wouldn't go wasting my time trying to get it to co-operate if its crap.

The dealership near me didn't even bother to notice the rear wheel being bent a bit. My sister had somehow managed to do that while the wheel was on our 300SD a few years ago. They also didn't notice the rust. Granted the car was last with them in the summer.

Since I'll have to take it back for an alignment, I'll ask the service adviser about the height values.

Well this guy does sound a lot better than the others - may be it was more of a "my mood" thing in my interpretation of his notes.