R107 Steering box adjustment? Really?
 

Regarding the procedure to "adjust steering torque" I am wondering if this is used to remove free play in the steering wheel. I have about 3/4" of play in the wheel. The other components in the steering system appear okay but I really need to check more carefully before pulling the steering box. I have been told one has to remove the steering box, exhaust manifold or both. What is correcct?

I have been told that the procedure may not help my problem and it is only for setting torque of the steering wheel and the free play is a worn worm gear and cannot be adjusted out.

Do I need a new steering box to eliminate this condition? It can't be. Please advise.

Seve
'85 500SL (Euro)

The box can be adjusted and it may be done with the box in the car. There is an adjustment screw on it. I cannot recite the specs of how to set the correct torque off the top of my head, but I am sure you will uncover this info if you do a search.

-Good luck

Too tight to believe.
 

Thank you for your response.

The adjustment is a like a screw and locknut on the top of the box. It is not adjusted by torque, but by position. I have read the factory manual and understand how it is to be done but the procedure is only to turn the screw 1/4 turn and test torque (on the steering wheel) then back out another 1/4 turn and measure again. The problem is how to access the screw and locknut.

One local MB dealer said they will drop the box to do it. A local Factory trained independent said you have to remove the exhaust manifold. There is no room between the motor and the steering box.

But I am equally concerned that the adjustment won't remove the steering play. Perhaps I need to check or have checked everything else in the steering system. One mechnic said he never got any results from adjusting the steering box.

Are there any common wear items that can cause this free play??

All advice is welcome.

Steve
'85 500sl (Euro)

Steering Box Adjustment
 

I recently started a thread on adjusting the steering box on my 1987 560 SL. It can be done with the box in the car, but it's not the easiest thing to do. And no, I didn't have to take the exhaust manifold out. What I did have to do was remove the heat shield on top of the exhaust manifold; two screws. Along with that I had to detach what I believe is the exhaust gas recirculation valve to get to the second heat shield screw. Once that's done, get a 19mm crows foot on the end of a universal joint and long 3/8" extension. This will allow you to break the nut loose. To adjust the screw, buy 6mm allen wrench with a ball end (as long as possible), cut the right angle (non-ball) end off it and slide it into a 6mm socket. You can then hold the lock nut with the crows foot while turning the adjustment screw with the allen head. To tighten the steering box, turn the screw counter-clockwise. By the way, I bought all of the necessary tools at Sears for less than $ 25.00.

Hope this helps.

Steve,

Having the same vehicle as yourself let me tell you my experience regarding adjusting the steering. One mechanic told me by looking at it that it was adjusted all the way out. Since the car only has 90,000 miles on it I couldn't believe it was adjusted out. My '82 300d has 275,000 miles on it and it still has adjustment left. This one just had to have more left in it.

Using this logic, I took it to the local MB dealership and watched the mechanic try to make the adjustment. He did get to it, but was unable to adjust it out any further. Cost me about a hundred bucks for that experience.

There is absolutely no space to get into the box--as you probably know--without doing some finagling. In this case, he wound up loosening a motor mount and jacking the motor up. He then placed a 2 x 4 block between the frame and the engine to give him a little workspace. Then, he was able to get to it from the top, but it was still extremely difficult and time consuming.

As was suggested above, he used a crow's foot and an allen wrench to make the adjustment. If you attempt this yourself, I wish you luck. He had a lift, a jack, and all the right tools, plus some know-how and it was still tough to do. One tip here is you need to mark the nut with some white paint or something to use as a frame of reference. Make sure you don't adjust it too tightly. If you do, the steering wheel won't straighten on it's own, but you'll have to turn the wheels back yourself.

I have 90,000 miles on my '85 500SL and the steering box was shot. I got a rebuilt box from ************************ for about $325.00 w/a 15% discount and a core charge of $125.00. Labor to replace it was about $400.00 BECAUSE they had to drop the exhaust pipes since they surround the box. In my case there was one bolt that wouldn't release and they wound up drilling it out with LOT of difficulty. Unfortunately, I had to pay for that difficulty.

To sum this up, try to figure out if you have any adjustment left. If it looks like there isn't or if it looks like it might be close, and you're paying to have it done, then I recommend you go ahead and replace the box. In the long run it might save you a few bucks.

Since I haven't come across many Euro '85 500SL's on this thread let me tell you what I've done to mine and, again, it only has 90,000 miles on it. I've replaced the front calipers, pads, tie rod ends, drag link, steering box, fuel pump, fuel accumulator, idle control unit, idle control valve, steering box, climate control unit, overload protection relay, and put a new soft top and rubber on it. Believe I've finally gotten it to a point where I can see daylight. Good think I got the car for a decent price since I've put about $4,000 more bucks into it.

As my son said right before we turned the corner when he took me to look at the car in Houston, "Dad, this car is a head turner!" He was right.

Cheers!

Don

Don

Steering Box Adjustment
 

Don,

My 87 560 SL only has 102,000 miles on it, and I have little or no information on its previous service history. The play in the steering box was such that it tended to wander on a straight road, requiring constant correction. Once I got past the aforementioned access issues, the adjustment seemed to work quite well. I'm in absolute agreement that one can't be too careful in making the adjustment. In this case, "less is more". Beter to have a little play than to overtighten and ruin the box. Changing it out sounded like a nightmare.

The play that s adjusted is between the reciprocating ball assembly and the pitman arm drive. This connection is a ball in socket with the ball being on the assembly and the socket a part of the pitman shaft.

The worse cases of tractability and seeming play can come from drawing the socket to harshly into the ball. This then drives the recirculating ball arrangement into constant verticle loading wearing the assembly. In this condition the steering drives the car. Normally the alignment and road drive the steering (untill driver corrected), when the box is tight in this manner the slight changes in road leave one constantly crossing the play of the ball assembly to minorly chase/correct the direction of travel. A most irritating and unsafe condition especially on varrying roads.

I only say this to emphasize that this point must be avoided. I have fixed a number of these situations over the years and many have been after the car had most of its suspension replaced chasing the problem. Many came after new owners took over after previous ones gave up. Don't get it too tight.

Thanks all + anything else to check?
 

Gentlemen,

Thank you all for your thoughtful responses. Thanks to Max for the fine description of his procedures, Don for history on an 80’s Euro SL (We need to stay in touch.) and Steve for the technical explanation of the mechanics of the box and Ali for a good start. It is more important than some think to explain why something is done a certain way other than simply what to do. And Steve, I have read some of your posts and published work and you are a master at explaining functionality.

Are there any specific things to check in the steering or suspension that could cause the free play? Any common wear items to check first? (This ~3/4” play exists with the car shut off as well as running.)

Considering the passable condition of the steering and how involved the project is, I may put it off. It seems important to make this adjustment because the manual says for a steering gear that has not been adjusted for a long time that there may be an area in the center with lower torque and that it cannot be adjusted out. I assume this does not mean free play but torque of the steering gearbox.

When I work up the gumption you will probably hear from me again.

Steve
’85 500SL Euro