So I've found out recently that the power steering pump for the 2.6 is NLA. I noticed that Pelican Parts sells a rebuilt unit from CM Hydraulics. However, you do have to deal with paying a core charge and then sending the dead one back.
Looked them up and found out that they're in Las Vegas and you can actually go there in person to pickup a freshly rebuilt pump. Since I had to go to Vegas anyways, I flew in with the old leaky pump and was able to exchange it on the spot.
I would definitely recommend calling CM Hydraulics directly if you need a power steering pump, steering gearbox, or smog pump rebuilt. They specialize in only older Mercedes and have a huge inventory.
They were very generous with their time as well and showed me their warehouse where all of the work is done.

 

how did you determine your power steeling pump was defective. I know ones on my 190 are not like new cars but I feel mine takes a lot of effort to turn the wheels.

 

In this case, the pulley seal started leaking and also there was play in the shaft.
The power steering pumps are pretty robust, most of the failures are due to old seals leaking.