Centering steering wheel after alignment
 

I just had a wheel alignment done on my 85 300D. The steering wheel is not centered. I have no reason to believe that the wheels are not aligned properly, and due to steering box play, I realize that it is a little difficult for alignment shop to center the steering wheel perfectly without several road tests and tweaking.

The idea of centering the steering wheel on these cars is a little questionable anyway, because due to free play, my experience is that depending on the slant of the road (left lane vs. center lane vs. right lane on a highway) you need to compensate by holding steering wheel to right or left anyway. By comparison, my wife's 97 volvo 850 tracks straight no matter what.

Nevertheless, my steering wheel is off center a little

My question is this: I would rather center the steering wheel myself to my liking rather than bring it back to the shop....this seems to be very simple... shorten tie rod on one side by half a turn, lengthen same on other side by half a turn...etc. etc.....

Will this throw off another aspect of the alignment (toe in, camber etc??). I dont think so...it seems that tie rod adjustments would be independent of other things, but I dont really know for sure.


Thanks,

Mark

Your car has a slot on the steering box into which a locking pin is inserted while aligning the front end. The pin locks the steering gear into the straight ahead position, guaranteeing the wheel is centered to the greatest extent possible. A shop which is familiar with MB would have used this to center the steering gear for a better result.

That said it is certainly possible to adequately center the wheel without locking it. How far off is yours? A cockeyed wheel is generally a sign of an alignment technician too lazy to do the job right. I'd suggest you take it back and have them either do it right or refund your money.

Yes, you can adjust the tie rods in equal increments to center the wheel. It will not change the alignment, though you'll likely alter the total toe a bit. Get it too far off and you'll see excessive wear on the front tires.

Ditto...

You would be surprised how many Off the Wall align shops
don't even know that Benz has an Index mark/pin lock set-up to insure a straight wheel built into the car.

That's why Benz familiar Techs should be sought out for accurate alignment...

I have seen reference made to this slot/locking pin before. Where is this located on the steering box? I have looked for it before without success and would like to point my alignment shop to it.

Thanks,

Mark

Mark,

I've had done exactly what you propose. The shop apparently did not know about the locking pin....and they overshot the centering the other way just a bit. I could live with it since I too have some free play and it was close.
The problem is that my tires are showing excessive wear on the outer edge on the drivers side, so the toe-in is definitely affected.
I would go back to the shop too.

There is an adjustment on the steering box that is supposed to help with the free play, I read the procedure in the archives but I don't know if it works.

Rgds, Ed

Mark -

Why don't you post your email address. I'll see if I can dig up a PDF file with information on the steering box. What I have is from the 124 CD, but the steering boxes are pretty much the same.

- Jim

That would be great
 

My email is mmalchik@gza.com

thanks

mark

I agree totally with el presidente.

To correct this properly, you need to turn the tie rods the same direction on both sides an equal amount to maintain correct toe while moving the steering wheel into aligned position.

In other words turn both sides say exactly one half turn in the same direction, then see where the wheel is. If you think about it a little, you will know which direction will move the wheel in the proper direction.

If it were me, I would recheck the toe after the wheel is centered.

Good luck,

I think it is also acceptable to move the steering wheel a couple of splines.. if that is easier...Greg

DO NOT just move the steering wheel; if your steering is off at the box, your turn signal cancelling will be off. Putting your steering wheel on center will not correct that.

I concur with the others: take it back and have them do it correctly. I am taking mine back for precisely that reason.

This assumes that yours is similar to my 85 300.

Peter
1985 300TD

just re-checked your post, and see you DO have an 85.

Do not just re-center your steering wheel.

Good luck
Peter

I only mentioned it because the Factory Shop Manual says it is ok... Greg

thought so too
 

Greg:

I have the factory manual as well. I also have first hand experience. I re-centered my wheel thinking the same thing BEFORE a front end job and alignment, and now my steering wheel is straight and my turn signal cancelling is off: works on left turns, but not on right, unless I bring it past center.

The steering column controls the turn signal function, and is essentially dependent on the steering box being on center, hence the notch and the pin setup for alignments. I suspect the alignment guys just centered the steering wheel, and did the wheel alignment.

Mark can center his steering wheel, but it may only be a cosmetic fix. His (and my) turning radii are off (left or right turns wider) and his signal function is probably off too.

Mark, can you tell?

Peter
1985 300TD

The function of the lock pin and it's geometry is to centralize the
pitman arms swing between left and right rotation.
If the pin is in the locked box position with the steering wheel not level, then the splines are off .[ which means the wheel has been removed at some time]
The steering wheel tilt can be a result of
not using the lock pin, but the main concern of using the pin lock is to have the pitman arm in the proper geometric position before making alignment adjustments.

Hmm... It's been ages since I've looked, and my memory isn't so good, but I could swear the 123 steering wheel was placed on a six sided hex shaft rather than a splined shaft. Hence the granularity of adjustment would be 60 degrees - hardly fine enough for this kind of detail work.

As well, the car will drive better with the steering box on center in the straight ahead position. The box has reduced play at straight ahead, presumably for better control. Off center it has more play, for reduced friction, I think. If the steering wheel has been changed, driving straight down the road means having the steering box off center - in the area where it has increased play. Check out the manual section on adjusting the steering gearbox freeplay - it has a graph showing the torque required to move the wheel at each point from lock to lock. The required effort is lower on the ends and highest in the middle.

alignment
 

Mark,
Saw your thread about your alignment problems. By all means take the car back to the shop. I have five of these 123s and the last one that a purchased, I had to take it back four times before I left that particular chain's shop and went to another of their shops where they had a technician who could think beyond what the computer indicated. Once you find one of these guys, find out his name and demand he do the work in the future.

Any slack that you have in your steering box can be adjusted by loosening the lock nut holding the set screw on the top of the steering box. Mercedes tightens the adjustment by running the set screw "OUT", not in. Give the set screw about one-half turn "OUT" lock it down and try that for awhile, adjust it more as needed, a little at a time. Be very careful not to get it too tight, it won't return to center when you round a corner, if it's too tight. Panic city!!!!

Hopes this helps,
Ben

How is the steering pin locked for alignment?
 

Greetings All,

Just curious as I need an aligment on my 300SD an I'd like to know the skippy before going to an alignment shop concerning the steering lock pin and where it's located etc. Can someone elaborate on what needs to be set before the technician gets their hands on the adjustment so my steering wheel stays straight? Any input would be great.

Charles