1966 230SL Power Steering Box

[Harry]

I am rebuilding my PS Box and had some questions for the forum, please.  This is a 1966 230SL, and the box has been leaking so I removed the assembly, removed the pitman arm and steering coupling, then began disassembling the unit itself.  I had looked across the forum and tech manual for guidance as I began the task, and printed off some relevant posts/articles.  I realized this evening that all of those pertained to manual steering.  I have removed the cover at the pitman arm, removed the shaft that it attaches to and began to remove the assembly that the steering shaft attaches to.  It appears that this assembly cannot be removed until the "valve assembly" is removed first because the outer diameter of the assembly won't clear the valve assembly.  So I removed the bolts securing the cap where the inlet and outlet lines connect but the cap still seems to be pretty tightly seated.  (See photo.)

I can see there is a gasket between this cap and the body of the box so it is clear it is removable but I am hesitant to pry it off until I checked with the forum.  I certainly don't want to muscle something that might still be attached in some manner.  At the opposite end of the body, there is a seat that a spring fits over (see that photo as well) but it doesn't have any visible means to grasp or loosen (to remove the valve assembly from that end).

I would very much appreciate some advice from others who have performed this task.  Also, if there is a kit that I should get, that would be helpful as well.  (I have a kit that I ordered but I think it may be for manual steering.)

Thanks very much,
Harry

[66andBlue]

Harry,
you already posted the same question here: http://www.sl113.org/forums/index.php?topic=19798.0 Reply #21.
Please avoid duplications - thanks!

[WRe]

Hi,
maybe this is helpful: http://www.mercedes-scheune.de/index.php/vollrestauration-w111-coupe/step-5-motor-achsen/servopumpe-restaurieren
...WRe

[Harry]

Alfred - my error.  The prior post was inadvertantly posted within a related topic and so was not in clear view under this section.  When I realized my mistake, I reposted to a more favorable location for a response (which was successful),  I will gladly remove the prior post if that's possible.  (It would beworth knowing in case of future errors!)

Apologies and thanks,
Harry

[Harry]

I completed my rebuild of this power steering box and thought that I would provide some instruction for those who take on this task in the future.  Dave Petryk's article (found on this forum) was very helpful.  Unfortunately though, it pertains to the manual box.  The powered unit is quite a bit different and brings some additional challenges in dis-assembly and assembly.

The first difference is encountered when trying to remove the steering assembly.  The valve assembly that runs perpendicular to the steering assembly has to be removed first because it will interfere with the assembly, preventing it from being removed.  Once the valve assembly has been pulled from its bore, the steering assembly will come free.

The Teflon ring is indeed challenging to install.  I would absolutely endorse the approach to heat to 80C in hot oil.  It is a little "toasty" to hold during installation because it's hot but I am confident that doing this cold would result in damaging the Teflon ring.

Dave used a chain wrench to remove the large nut off of the sting assembly housing/cap, and I did as well.  The important thing here is to not tighten the vise against the nut.  The vise should only be very lightly snugged (not enough to hold the unit in the vise).  The issue is that this is a large, thin walled nut that is easily compressed under the large forces that the vise can apply.  It can easily be squeezed so tightly that the jaws of the vise are actually clamping it securely to the housing.  Set the vise such that the jaws fit about like a wrench would fit.  That makes this operation a challenge because the unit on a power system is heavy.  I would recommend using the 55mm wrench or socket but that's an expensive tool that will probably only see use on this job.

Most important is reassembly of the unit.  The steering assembly has to be installed in the correct orientation such that the "blade" is going to fit within the slot of the valve assembly (which needs to be facing down towards the steering assembly).  The steering assembly should be rotated enough to turn the blade up against the opposite side of the housing from which the pitman is inserted.  As the valve assembly is carefully inserted from that side into the housing/body, you have to rotate the steering assembly such that the blade comes into the slot on the valve assembly as the assembly is being fully inserted. This took me a few tries because visibility is so poor and shining a light into that area results with a lot of reflection in your eyes.  Once the valve assembly is fully in, be sure the blade on the steering assembly is in position.  I did this by rotating the input shaft back and forth and listening (as well as trying to visually ensure it was correctly located).  If it is in the slot, you won't hear any "knocking" by rotating the input shaft back and forth.  If you hear knocking as you do this rotation, the blade is not in position and you need to start over.

As with most jobs, doing this again would be very straightforward having this experience behind me.  I hope I don't have to repeat the performance!

Thanks to the forum as always!