Centering the steering wheel
 

Last week, I had the local Les Schwab shop align our '85 300D. The day before, I had installed new tie rods, so the alignment was no doubt out of spec when I delivered it to LS.

Among other things, the steering wheel had to be held somewhat to the left for the car to travel straight down the road. Prior to my installing the tie rods, this had not been the case. So, I explained the situation to the LS guy and asked him to straighten the wheel. He wasn't so sure he could do that and, sure enough, he didn't. Otherwise, the car drives fine.

My question: I recall from forum discussions that the first step in aligning a 123 is to lock the steering box in the straight ahead position. I would appreciate that this piece of information be confirmed before I harass the fellow who did the alignment. If any of you could append a pertinent page from the Benz manual, that would be especially appreciated.

Thanks,

Phil
'85 300D, the queen's carriage
'84 Euro 300D, peasant class

I can't be of too much help but I believe there is a "pin" that goes into the steering box to lock it in place.

P'bert,

I have the page in a manual for the W115 chassis, not the W123 chassis. However, I think the procedure will be similar.

In the W115 chassis, the under dash cladding to hide the guts is not as elaborate as it is on the W123, so that will be a difference. I think on the W123 you have to remove the formed plastic covering first to get access to the steering spindle tube while this stuff was pretty much in plain view on a W115 if you got under the dash. The steering spindle is inside this tube and about half way from the steering wheel to the hole in the firewall where the spindle shaft assembly goes into the engine compartment, there is a small hole in the steering spindle tube. When the steering wheel is in the straight ahead position, a hole in the spindle will line up with the hole in the tube. It actually does it once per rev of the steering wheel so you have to put the wheel in the approximate straight ahead position, then line the holes up. If you miss it by a revolution, or, as someone on the board experienced, get the steering wheel a significant angle out of alignment and just remount the steering wheel a few splines off, the blinkers will not turn on and off as you expect. There is a special tool to be made by hand that fits in there, but it is unnecessarily overspecified in the drawing. In reality it is a small rod, about 6mm in diameter and a few inches long. If you have a selection of cotter pins I think you can find one that fits.

Anyway, with the steering wheel locked with the centering pin, you go about your business of aligning the front end (I believe toe-in is the parameter of greatest sensitivity, although on my old 1975 240D chasing caster and camber seemed interdependent and to affect toe-in too, or atleast the straight line performance). I believe this is not the case with the W123 though as the front suspension and steering geometry/set up is different - meaning the toe-in or straight line performance influence from the camber and caster adjustments.

Good luck and I hope this helps. If someone with a set of W123 manuals can confirm this I think it will make P'bert a little more comfortable. Jim

Almost NO independent shops can properly align any Mercedes. That's because there are two special tools needed that usually only the dealer has, unless the shop does a LOT of MB's and actually has a clue (which is rare). The two tools are:

1- Lock pin for centering the steering gearbox

2- Spreader bar to tension the front wheels to correctly set toe

Ask any shop if they have these before you let them touch your Benz. If they don't know what you're talking about, or worse yet tell you they're not needed, walk away. It's worth paying the dealer $100 to have it done properly. I like to verify that all steering & suspension links are good, that way you don't have to get *another* alignment after a new tie rod is installed, etc. The dealer will usually call you & tell you if anything needs replacement while the tech is doing the alignment to prevent that problem. BT, DT.

For the record, I do 99% of my own work on my MB's. I let the dealer do the alignments and sometimes the tranny fluid changes. I never let ANY generic shop touch the car. On rare occasions I'll let an independent MB specialist do a job that requires tools I don't have (example, the OM603 front crank seal).

I'd bite the bullet and take the car to the dealer to have the alignment (and steering wheel) fixed.

I brought mine to Firestone for a front end alignment. When I brought it there I had to hold the wheel about 9 o'clock to drive straight. After, I have to hold it at 11:30 o'clock. I have been thinking about adjusting the steeringwheel to make up for this, it's just not high enough on my list.

You don't "adjust the steering wheel". You lock the steering gearbox in place with the special tool and the wheel should be straight - if not, THEN the wheel gets removed & re-centered with the box locked on center. With that set properly, then the tie rods are adjusted equally to correct the alignment. If the box is off-center with the car driving straight, the steering won't return properly. Get the car aligned right at the dealer. Like I said, this is one of those few things you REALLY need to ONLY have done at the dealer (or a VERY competent independant shop with the right tools, as mentioned in my prior post.)