Mercedes-Benz Ponton Kugelumlauflenkung, steeringbox, 71717, © Daimler AG
Intermediate steering lever and steering coupling
Well, what to say about these ones? Not much, sandblasted the steering lever, painted it with DB7164 and changed sealing ring! Everything else was in order. And with the coupling it was the same. The joint disk was kept, the grounding cable is however new. The screws were grinded and yellow plated.
Everyone that I've spoken with have said "no, don't dismantle the steering box, there's never nothing wrong with those". I'm very glad I did it anyway and it wasn't difficult either. But please, don't forget to mark every part's position, take photos and draw a lot of sketches of everything. And you do need some special tools as well as a strong arm when you remove the pitman arm as well as when you put it back! And with a bit of luck, it isn't expensive either! I didn't have luck...
This one took some time. The first thing that didn't work was the removal of the pitman arm. I broke two standard pullers before I understood that there were special pitman arm pullers. They were however much too expensive so I handed the steering box over to Rulle, now at Mercedes-Benz/Bernats Bil in Västberga. On the same time he unfastened the 55mm nut that locks the adjusting ring on top of the steering box. Well, no wonder that I couldn't remove the pitman arm myself though, the nut is tightened with 250Nm. For the assembly I bought a new torque wrench, a big one as well as an equally big 55mm wrench.
A picture of the Ponton steering. Copied from the Ponton page's article "Recirculating Ball Steering"
Forget that you ever seen the tool on the second picture. It worked OK but I bought a better tool for the assembly! Well, what does the third, low quality picture show you? Maybe a dirty inside of a steering box. The fourth picture shows you one way to remove the inner rings of the bearings from the steering worm (?). And here comes the costs if you're not lucky. These bearings are a special type, however still available. There is no other bearing manufacturer anywhere in the world making an equivalent to this FAG bearing. That compels the conclusion that FAG makes these bearings in small quantities for Mercedes only. There is probably no other application for this particular bearing. Soooo, you'll have to pay something like $100-145 for it (year 2002)! So if you find a bearing with the following label, buy it if it costs less than above - if you're planning to restore your steering box of course: "FAG F (or E) Germany FOR 502619", original MB-number 000 981 03 18
According to FAG it was later replaced by a bearing called 502619B. This bearing was also used in the truck L408 (1966-) as well as in their busses O319D+B (1966 - ). Its measurements are:
- Inner diameter: 19,6 mm
- Outer diameter: 44,475 mm
- Width (?):14,448 mm
One of my bearings was in a very bad condition, the other one was almost OK. According to my father it was still usable and would last the rest of the cars life. Feeling a bit ashamed I ordered only one bearing. (Un)fortunately, Karasch, who offered the best price by far, sent me two bearings. A lot of money poorer (compared to what I got so to speak), I was a very happy steering box restorer!
And here's everything, either brand new (like ball bearings, sealings and gaskets) or cleaned and painted or yellow plated. When assembling bearing rings you must have god connection to the one who rules in the kitchen. Put the part that you want to shrink (in case with the steering worm; the shaft ) in the freezer, and the part that you want to expand (in the case with the steering worm; the inner ring of the bearing, in the case with one of the outer rings; the whole steering box) in the oven. Then drop the hot part on/in the cold part, finalize it with a couple of distinct blows on the ring (in this case...). I used a hammer on a "soft" brass stick or tube.
Give yourself some time when you adjust the pressure screw and re-check it when you have tightened the nut. And enjoy yourself when you tighten the nut for the pitman arm with 250Nm, without risking the steering worm. The last picture shows you the almost complete steering box. Some detailing still remains.