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300D steering box adjustment

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monarchd's picture
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Does anyone know if the steering gear box on the 300D series has an adjustment to take up any slack in the mesh of the gears? Seems to me I read somewhere where it does but I can not find the source where I read it. On the top of the box there is an allen screw with a locknut, could this be it and how much slack will it take up. Thanks.

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Adamson's picture
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1951 220 SEDAN
1961 190Db

There are several posts on the steering box. Go to the search button at the top of this page and type in steering box.

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Tom Hanson's picture
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1970 300SEL 6.3

You found the correct spot for the adjustment. Don't overtighten it. Check for worn steering and suspension components as well.

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Tom Hanson
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Mercedes-Benz Classic Center USA
MBUSA, LLC
thomas.hanson@mbusa.com
949 598-4842 direct.

Prior MB cars: 2010 ML350 Bluetec, 2003 C320 Coupe, 1986 300SDL, 1971 300SEL 6.3, 1973 450SE, 1959 220S, 2011 C300

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Thank you Tom, I jst purchased this 300D with92,000 miles from the original owner who had all of the maint records. It shows a complete front end rework less than 10,000 miles ago. I hope the adjustment does the trick. As the previous reply suggested I did do a search but only come up with my question. Maybe I'm doing something wrong. Thanks again. Paul

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D.L. SWINFORD's picture
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Yes there is

Paul;
There is an adjustment for setting the mesh of the sector and worm gears in your steering gear; BUT tread softly.
There should be NO wear in the steering gear even if it was run with no fluid; the wear would be in the power steering pump.
To adjust the mesh is no easy job.
First you disconnect the pitman arm from the steering gear.
Next you turn the steering wheel and find high center.
Turn one way to the end then opposite and count the number of turns finnally half way back to the middle where the steering wheel should be straight.
You loosen the lock nut and insert the allen wrench.
Using an ounce spring scale you tighten the allen screw until you get the proper preload between the 2 gears then tighten the lock nut.
Recheck your preload.
Should you over tighten the gear mesh your gear will dart both right and left off of high center. This is because the torsion/trust bearing in the gear is asking for power assist.
After all of my rambling on, I repeat; your gear should not require adjusting.
The 2 300's I've had, both with over 200k miles, did not required a gear adjustment.
Look elsewhere for your loose steering.
Maybe someone else can help.
Happy Trails Beep Beep from the long winded Spiderman on the Gulf Coast, Don :p

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Robby Ackerman's picture
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You loosen that big locknut on top of the steering box and turn the threaded Allen pin counter clockwise, up not down, to remove slack. Turn no more than necessary.

This of course assumes the slack is in the box. It is easy enough to turn the steering column and see if the arm coming out of the bottom of the box immediately moves or not.

Will Samples in Texas does a great job rebuilding MB steering boxes.

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1960 190 SL
1983 300 D (WVO)
1984 190E 2.3-16 / Mosselman Turbo System & Dinan suspension
1984 190E 2.3-16 / Delsing Motorsport suspension
1992 500SL


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D.L. SWINFORD's picture
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Not Up

Robby;
I don't always mean to be on the left; but you've made an error in your instruction in what direction to turn the adjusting screw to remove the slack, if that is where the slack is, by turning the screw up.
You are turning the screw threaded in the sector shaft civer.
The screw is attached to the sector shaft with a retaining ring.
If you turn the screw up or out you will lift the sector shaft from meshing in the tapered teeth of the worm gear.
You turn the screw in or down to crate more interferance between the two.
Too deep and the gear will bind off off dead center.
Per the service manual, in car adjustment is performed with a torque wrench not an ounce scale, both methods work.
Happy Trails Beep Beep from screwy Spiderman on the Gulf Coast, Don :p

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Robby Ackerman's picture
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Don

I don't doubt for a minute what you wrote. Are we taking about the same gear box? I'm thinking of a 123 300D. It is counter-intuitive, but I'm sure I've been adjusting the threaded pin up to remove the slack.

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1960 190 SL
1983 300 D (WVO)
1984 190E 2.3-16 / Mosselman Turbo System & Dinan suspension
1984 190E 2.3-16 / Delsing Motorsport suspension
1992 500SL


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D.L. SWINFORD's picture
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What can I say?

Robby;
I have here in front of me the service Manual for the W123.
All steering gears are the same; be it domestic or imported, Power or manual; they are "Cirulating Ball-nut.
The change came by the cost reduction to manufacture "Rack and pinion"(CHEAP and don't last as long) Die castings instead of ferrus castings.
If you will look at Job No.46.7-070/1 in the service Manual, Chassis and Body, series 123, Vol 1. it will take you through the procedure for servicing the Circulating ball/nut steering gear.
I'm sorry Robby.
Happy Trails Beep Beep from The Spiderman on the Gulf Coast, Don:p

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Robby Ackerman's picture
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I adjusted my daughter's steering on her 123 300 D this weekend and I turned the allen screw counter clockwise to take out the slack.

Don & I sound as bad as Click and Clack when it comes to giving advice. :)

__________________

1960 190 SL
1983 300 D (WVO)
1984 190E 2.3-16 / Mosselman Turbo System & Dinan suspension
1984 190E 2.3-16 / Delsing Motorsport suspension
1992 500SL


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Palangi's picture
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I sure enjoy listening to Click and Clack, but last week they told a caller with a Porsche 912 that her heater core was leaking.

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AND THE WINNER IS?

First prize for answering correctly, "which way do you turn adjusting screw#47 to remove excess play from steering gear?" Goes to ROBBY ACKERMAN !!!!!

I have been adjusting them that way by the book and just had a look at my microfiche for the 123 steering gear. Turn to the left to remove loose play.

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New York club member since 1976.

Continuous Mercedes ownership since 1964.

1993 300SD with '99 606 engine. 111,040 miles.
1994 S350   75,238 miles
1995 S350 148,124 miles.
1996 S420 with '99 606 engine  Sold
1999 S600  one of 14 imported  Sold 
1989 Bentley 8  Sold at 40,000 miles.

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D.L. SWINFORD's picture
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cLICK AND CLACK

This is clack.
Do what you think or know is right.
When if ever my gear needs adjusting I'm going to do it the wrong way.
I stand corrected by the majority.
But my manual tells me wrong.
Happy Trails Beep Beep from the wrong way Spiderman on the Gulf Coast, Don

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Check out the following link for a real good explanation of the technique in question.

http://www.mercedesshop.com/shopforum/showthread.php3?s=&threadid=100010

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New York club member since 1976.

Continuous Mercedes ownership since 1964.

1993 300SD with '99 606 engine. 111,040 miles.
1994 S350   75,238 miles
1995 S350 148,124 miles.
1996 S420 with '99 606 engine  Sold
1999 S600  one of 14 imported  Sold 
1989 Bentley 8  Sold at 40,000 miles.

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D.L. SWINFORD's picture
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Good Post

jtripp;
What an excellent instruction on steering gear adjusting.
To all who are going to adjust thier steering gear;
With the years I spent at Saginaw Steering Div. of Gm, I have never seen the play removed from the steering gear by lifting the sector gear from the worm gear.
I will stand corrected by so many who have done just the opposite from what I see and have done.
Happy Trails Beep Beep from the Spiderman on the Gulf Coast, Don

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Robby Ackerman's picture
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Are there other repairs that come to mind that are counter-intuitive?

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1960 190 SL
1983 300 D (WVO)
1984 190E 2.3-16 / Mosselman Turbo System & Dinan suspension
1984 190E 2.3-16 / Delsing Motorsport suspension
1992 500SL


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Robby - move/copy this thread...

to the W123 section, since it's topical to our cars

p.s. I'm going to start watching the obits in Don's newspaper...I want to buy his 300D when he goes to the big junkyard in the sky!

Jim Grillot (not verified)
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Are you folks sure that the adjusting screw doesn't have left hand threads? So that turning the screw ccw = driving the worm and sector closer together?

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D.L. SWINFORD's picture
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Now You're Thinking

Jim:
I have been shot from the saddle on just this subject; "Adjusting Steering Gear".
In reviewing the mechanical drawings in the shop manual that is the only logical reason for turning the adjusting screw c.c.w.
But with so many who have had personal experience adjusting thiers I hesitated to enter this reasoning.
Thank you for breaking the ice.
Happy Trails Beep Beep from The Spiderman on the Gulf Coast Don,:p :p :p

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Robby Ackerman's picture
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The threads are normal as screwing it CCW the threaded pin comes up and out.

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1960 190 SL
1983 300 D (WVO)
1984 190E 2.3-16 / Mosselman Turbo System & Dinan suspension
1984 190E 2.3-16 / Delsing Motorsport suspension
1992 500SL


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