They weren't designed "sloppy from the factory." Recirculating ball steering boxes are pretty precise and provide incredibly smooth operation, but as they have half a dozen more joints in the system than a rack and pinion setup, there's always going to be more play. A rack and pinion setup can have play in the rack, and two end connections which can each have play. Compare that to a recirculating ball setup which can have box play, center link play on both ends, tie rod play on both ends, and an idler arm with play; and you have more sources of play in the system.

The issue is that over time you'll see more play in a recirculating ball system than a rack and pinion, and it will be more expensive to replace.


The "adjustment nut" isn't really for adjusting play out of the system after long term use. It's there to adjust the initial lash/spacing between the teeth of the pitman arm shaft and the working piston. Yes, it can be used to compensate for wear, but only so much. Reconditioning the seals of the box, refreshing the pump and maintaining the steering linkage will do much more than touching that screw.

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Onus probandi incumbit ei qui dicit, non ei qui negat

I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]

I agree with everything except the 2" free play being fine. It can be adjusted until there is 1/8" of play which is what I want. I want the steering crisp and not have to play the wheel back and fourth to keep it running straight.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I looked for a while for a rebuilder who would rebuild my gearbox. I had the experience I mentioned about replacing boxes on my last W123.

The other rebuilders I spoke to would not rebuild my box, they would only take it as a core. I asked them if they would send me a box with 2" of play in it and they said that was well within MB specs and I may end up receiving a box that is like that.

Dkr.

Yes, W123's all came with steering locks but I've seen more than a few that had this disabled, a bad idea IMO .

As mentioned, the steering box is the VERY LAST THING that should be adjusted /checked .

I've had to adjust the steering box on all but one of myW123's and done carefully(you DO NOT want zero play in it !) it's helpful and the adjustment lasts years and years .

Changing the fluid (ATF) and filter is wise too ~ I always find black or brown (burned) ATF in there and accumulated sludge too.

I drain the system and use lint free towels to wipe out the old sludge and gunk before installing a new filter and refilling the system and bleeding it out .

I usually have to replace the ATF two or three times before it remains red and sweet smelling ~ bitter or burnt smelling ATF doesn't lubricate properly .

I too do not except 2" of play as I'm driving to be acceptable .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

I have a bit of steering play in my 1984 and 1985 (maybe +/-2 deg). I have replaced all the tie-rod ends plus the steering damper in the 1985, and the idler arm pivot appears tight. The problem appears to be in the gearbox, looking for play with the engine running and turning the steering shaft back and forth by hand. Mine have the sector shaft adjustment bolt full out, which is ~7 threads showing, so no more I can adjust there.

I have looked for gearboxes when at the junkyard, but all showed similar "full out" adjustment screws, except one which showed only 2 threads. Thought I lucked out, but before going to the effort of removing it, I did the sector adjustment and the bolt had to back out all the way before the play was removed (not totally), so somebody must have been driving it with +/-20 deg play in the steering, as you see in old movies of 1930's cars. In Indonesia we were once driven in a Navy van where the driver was jiggering the steering wheel back and forth like that. A good pothole and we could have gone in the ditch. They must not have good mechanics at that base.

I later pulled a junkyard gearbox to play with. Note that W123 (300D) and W126 (300SD) are different gearboxes even in same year. Someday I will take it apart and see if something simple like replacing the recirculating balls or a shaft bushing/bearing eliminates the play. I haven't seen any places which rebuild them affordably and even used ones on ebay are pricey.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Just for a frame of reference ... if you do a first time gently adjust ...about how many turns or large a fraction of a turn would you generally expect to go from 2 inch to one inch play? I never tried this.

adjust until you feel a bit of drag then loosen it a smidge. When the play is gone and it turns freely lock the adjuster down.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Best approach is to adjust the screw counter clockwise quarter turn and drive it for a few days. Then adjust it again. Adjust until you have just a little play. If you do that and the friction increases markedly at the end of steering travel then either your box is kaput or you have play some where else in the steering.

When these threads pop up, I guess I don't follow the logic of where your steering is loose, you tighten the steering box, the play in the steering goes away, and somehow your real problem is worn out tie rods and ball joints, et cetera. Like, the steering box is literally only the first link in the chain, how could it magically take the play out of all the other components if they're worn out? It seems more like: you adjust your steering box and there's still a lot of play, therefore the real problem is the other components. If you adjust it and it feels 200% better then a worn box is the cause.

Hence me, in my newbie state a decade ago, following the idea of "replace all the expensive stuff first because the box isn't the problem" that many promote. And when that didn't work, the steering box adjustment literally took the steering from being little better than a child's wagon to "no sports car but at least it stays in the lane now..."

Nobody said to replace anything that is not worn and loose. We did say check for play in the linkages first. This simply involves lifting the car off the wheels and trying all the linkages to see if any are worn. You can adjust the box at any time but it is possible that the box could be fine and in adjustment and you have a loose worn tie rod fall off and you have an accident.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Maybe a quarter to half of a turn?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

So you replaced all your steering and ball joints without checking them for looseness and then found the steering box needed adjustment?

And just as a reference replacing the box is hardly cheap, in my book anyhow.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Very important to keep turning the steering back and forth thru the center point. The sector shaft is tightest in the center, so if you took out all play with it off-center, it could bind when going thru the center. This is true of gear-boxes on all models I have fooled with. Also, insure you secure the allen bolt with a wrench while tightening the jam nut, so you don't change the setting.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Where is the jam nut adjuster located on the box? From what angle is it accessed?

That wasn't my point at all. And adjusting the steering box is free.