xxaarraa

Another topic that seems to have hit or miss information on the Internet, so cataloging this here for future passers by. 2013 G63 with what I believe is the "LS2" V8 steering gear box.

I was noticing a small leak on my steering box itself. Wasn't too bad, and losing fluid at the rate of about 1/3 quart every 10k miles. Finally got around to trouble shooting. Lof of Internet wisdom said to check the hoses (particilarly the return hose) first, and mine were all dry. The entire top of my box was dry and the leak was around this nut:


The 19mm nut has a pressure valve/ball inside it. I believe it is a steering limiter pressure valve. The 10mm nut to the side seems to have the sole purpose of holding on the grooved locking plate around the 19mm nut to ensure it doesn't spin in or out. Tightening this 19mm nut half a turn stopped my leak. Some useful information in this thread:
1998 w463 Steering Gear Adjustment - Club G-Wagen Forum (clubgwagen.com)


While I was in there and had the wheel well liner off, I decided to tighten the pitman arm lash to tighten up the on center feeling of the power steering. I have 33" knobby tires on and 87k on the ODO, so the steering was a bit mushy on center. Above the steering limiter pressure valve pictured above, is another 19mm nut with a 6mm allen inside it.



To tighten, you break the 19mm nut loose, then go eigth to quarter turn COUNTER CLOCKWISE on the allen. Then tighten the 19mm back. Over tightening the allen causes accelerated wear of the box internals I believe, so its best to do it an eigth of a turn at a time. If you don't already have them, offset box wrenches are needed for this job. Like these: