560sl Steering Gearbox Adjustment

[MUDTEX]

Steering is a little loose. I have replace the steering coupler. Look like the slack is in the box. What the best way to adjust the box?

Thanks, Keith Davis

[nobby]

Adjusting the box is the easy part...allan key and a wrench....loosen the locknut with the wrench, turn the screw with the allan key COUNTERCLOCKWISE in small increments. Too tight will shorten the life of the box.

Getting to the box on a 560 is another thing altogether. I have not done it but have heard of guys removing the exhaust manifold and various other parts to access. Maybe someone else can chime in here....

[Roncallo]

Originally Posted by nobby

Adjusting the box is the easy part...allan key and a wrench....loosen the locknut with the wrench, turn the screw with the allan key COUNTERCLOCKWISE in small increments. Too tight will shorten the life of the box.

Getting to the box on a 560 is another thing altogether. I have not done it but have heard of guys removing the exhaust manifold and various other parts to access. Maybe someone else can chime in here....

On the 560SL, I was able to do this job by accessing the bolt and jamb nut through the exhaust manifold. using a hex bit socket attached to a 12" swivel extension and a 19mm crowsfoot wrench on a universal with a 12" extension. A swivel extension is an extension sold by Snap-On, and I'm sure others by now, that has a beveled male end allowing a socket to swivel just a few degrees.

To do this properly you should disconnect the pitman arm. remove the airbag if equipt and rotate the steearing column from full lock to lock slowly with an inch pound torque wrench on the bolt that holds the stearing wheel on. The required running torque for this is available on the 107 service CD under the PS gearbox overhaul section. Since the published running torque is for the gearbox removed from the car, add about 3 inch-pounds to compensate for the stearing column bearing drag. The published running torque is not just one number. It is actually a graph that has higher torque with the wheel near center. If you have higher torques at the ends then the box will have to be replaced.

Note This adjustment screw is the most abused screw in the industy.

John Roncallo

[Strife]

I think the real danger here is going from rack-and-pinion steering in a modern car to this car and thinking that it's loose. I doubt if the steering was as tight as a modern rack and pinion mechanism with 100K on it when the 107SL was new. The book says some play is normal. Overtightening the box will cause loss of return-to-center (pretty dangerous) and/or an exponentially faster wearing out of the gearbox requiring complete replacement ($$$$).

[nobby]

The steering and the clutch are hard to get used to at the beginning of the season after driving my Honda Civic all winter. Now, however, I have been driving my SL so much that driving the Honda feels weird. I even think my wife's GMC Safari has more "play" than my SL.
The play will never be eliminated but after a total front end check, steering coupler replacement and small adjustment it can be made tolerable or better yet...WITHIN SPEC... which is something like an inch total play (or 2.5 cm.)

I wouldn't touch the geerbox until I made sure the rag jont, tie rods, drag link, idler arms, and wheel bearings were all up to spec. If the box is overtightened it can break teeth when the wheel is in the center postion. Also, on R107 and w114/w115 cars the three bolts hold the box to the unibody should be torqued to spec every 30k or so, or they will come loose and make for a wandering panzerwagen.

[davestlouis]

My 86 560SL had atrocious steering play until I sort-of fixed the PS fluid leak...now it leaks much slower and the car doesn't wander on the highway. I wonder if aerated fluid would have caused the loose feeling?

[davestlouis]

Either that, or I'm getting used to the way it drives and I'm not weaving all over the road.

An old time Mercedes tech once told me these cars are very sensitive to camber changes in the road, and tire pressure. It's hard to switch back and forth from modern rack and pinion to one of these cars.