Steering box adjustment clarification......

[DieselHead]

I'm interested in fooling with the adjustment bolt on the steering box to try and take out some of the play in my wheel. I have read through some of the threads in the archieve but I still need some clarification on something. I have a 1983 300D. Is it correct to say that I need to turn the allen head bolt COUNTERCLOCKWISE to remove play? Or is it Clockwise? Thanks

Alex

I think the mystery of the 123 steering box is a sort of sick joke. It has to be a joke that they ended up with something so bad in an otherwise masterpiece of an automobile.

There are several pro tech's who frequent this site who say that you should not touch the adjustment, period.

That said there have been a number of people mess with these boxes. I see very few 123's with a tight box, but I've never been able to tighten one up satisfactorily.

About the best I've been able to do is; hold the allen screw firmly in it's position and loosen the nut completely with maybe a half turn of the nut, then turn the allen screw counterclockwise ever so slowly until you feel the slightest resistance. Then, hold the allen in that position while tightening the nut. You may have to tighten the nut several times to get the allen in that spot after the locknut is tightened.

Also, raise the front of the car and check the tie rod ends and idler arm for slack.

I hope this helps.

[DieselHead]

Thanks Larry, I'll try this adjustment tomorrow. I hope it helps.

Alex

[240Joe]

Here's my experience on the steering box adjustment. When I first bought by 240D, I brought it to an independent who was not experienced with Mercedes, and he told me you have to turn clockwise to tighten it, and mine was as tight as he could get it. It still had about 1 to 1 1/4 inch slack as measured on the steering wheel...too much for me.

So I brought it to someone who had real Mercedes experience, and he tighten it by turning it counterclock. He made it near perfect...and charged me about $100 for it.

After about 6 years of driving, it got somewhat loose again, so this time I attacked it. I held the allen screw stationary and loosen the locknut a full turn. Then I turned the allen screw counterclock an eighth of a turn and locked the nut back down. Off for a test drive. I did this about 3 times, until it was too tight and the wheel wouldn't return properly after a turn. Then I moved it clockwise to loosen it maybe 1/16 to 1/8 a turn... and it's perfect again.

It took me 2 or 3 hours of playing, but I think they can be adjusted, at least until the whole box needs replacement.

PS The first adjustment was at 155kmiles, and the second at 240kmiles. Hopefully, the box will outlast the car.

HTH

Joe

[ricali]

this will tell everybody how dumb I am. Ihave owned 240's since 1975. I got rid of that one at 100K because some told me it wouldn't last much longer and they cost a lot to repair so I traded in for a nice new 79 olds diesel
that's another story.
back to the steering box I never adjusted one right until 2 months ago when I got it off aforum

[CSchmidt]

Folks,

I'm a new member, watching and learning and hoping to buy my first diesel soon... so my past experience may not apply.

I working with american cars with the recirculating ball steering, they would get loose. I haven't seen a MB adjustment, but it sounds similar to the american version, a screw/bolt going into the box with a locking nut to prevent it from moving. You adjust it in a similar way, loosen the nut turn the screw/bolt the appropriate way, and then tighten down the nut to prevent changes.

Now for the (potential) advice, the steering box wears more in the center due to more frequent use- making the feel loose. If you tighten the adjustment screw too much it can bind as it gets to the less worn edges. After you adjust it carefully test a full lock to lock at a slow speed to make sure it will turn back as expected.

Thanks again for all the wonderful help and advice here. I look forward to learning much more and being an MB owner soon!

Chuck

Good advice from all. The 123 steering box, as far as adjustment does not act like an American box. American boxes are very easy and predictable to adjust. Plus on an American box you turn clockwise to tighten.

Yes, there's good advice and warning here about getting it too tight. Not only can you get it so tight that it won't return after a corner, but you can get it a little tight in which case you have to tug ever so slightly to keep the car centered in the lane while going down a straight road. On a long haul it will wear you out, mentally, not physically.

Also these boxes do some wierd things. If you just starting torquing on that allen bolt, it moves something in there that's a tight fit. Don't torque the Allen screw hard.

Good luck,

[Arthur Dalton]

Not sure on your box, but the adjuster on ones I have worked on only tightens/loosens a friction block. Very tricky and should be done by the book. Too tight causes binding.
Most worn boxes have excessive end play in the worm gear
and this requires taking the box out and adjusting the end ring
at the input shaft.
Friction block adjustment will not help excessive worm gear wear/end play.

Yes, the nut at the top of the box can tighten worn bearings. Some of the nuts are large hex, and some have notches in which you can use a punch to tighten. Be very careful not to get the big nut too tight. I have never taken a box out to tighten this. The only ones I've ever tightened have had the spanner notches and I tightened them with the box in the car.

Good luck,

[Douglas Broome]

I did the tightening on my steering box for my 1977 240D. Loosen locknut while holding alloen screw in place. Then turn allen screy no mkore than 1/8 tuen at a time. At all costs avoind overtigntening the allen bolt as this wuill crusch sometuing inside. Trial and error. Made a good difference in my steering.

FYI, be sure at the same time to tighten the three steering box mounting bolts inside the left front wheel well. Don't loosen them. Takes 15mm socket. torque to 58 lbft.

[diesel don]

I got lucky as I untighted the lock nut without holding the allen screw in place. Both turned at once.

Fortunately I was able to recover. In turning the allen counter-clockwise, I was able to find the right spot and eventually took out all the play without losing the wheel's ability to return on its own.

The car's tightness in steering feels new, yet I hope that I didn't screw something up in there by overdoing it at first.

Don

If it's working well now, you didn't screw anything up. I've had this luck with these steering boxes a few times. If you get it right, you think you're driving a new car.

Good job,

[DieselHead]

I just did the steering box adjustment and I'm not quite sure if I got it right. All in all, I probably turned the allen screw a full turn counterclockwise (with multiple test drives of course). The steering is much much tighter, and requires more effort (which to me feels good) but I'm not sure if I've over done it. The way I see it, because the steering can rebound on its own after a turn, it should be ok. Is this sound reasoning? I don't want to shorten the life of my steering box. My car used to wander all over the road, especially on highways and on roads with high cross winds. I hope this helps to eliminate that. Thanks

Alex

[DieselHead]

I just took my car out to run to the store and noticed that while the steering wheel rebounds, it doesn't return all the way back to center. For the last few degrees you have to tug it back to center. Is this too tight?

Alex

[Douglas Broome]

A full turn seems like huge amount. Still, after you were done, how nuch play was left in the steering wheel on the outsude. The width of one finger up to one inch should be an acceptable rule of thumb, to coin a pun.