David
The steering assist was probably an after market attachment that somebody put on when the machine was new. I asked the question before on the board and nobody really seemed to know what brand it was. Basically it is automotive type power steering pump with a dash extension and a valve with two levers that only pull out about an inch. hyd. hoses go from the pump to the valve and then where the steering clutch link went, they installed two hydraulic cylinders. The system is simple and works good but I haven't really found any adjustment procedures. You pull on the lever and the cylinder fully strokes to release the clutches.
The history of the machine is somebody was in the demolition business and bought two D8's out of Oklahoma. He had them for about five years and never really used them maybe only once or twice.
He had a lot of stuff on his property and said that he needed to clean it up and if he couldn't sell them he would have the scrap iron people come get them. I told him that I would help him sell them, but when I saw this one I decided that I had to have it. The other machine had a cable blade and if I had the land I would have kept both of them but I ended up buying both and sold the blade machine the same day I paid for them. I sold it for enough to pay for mine. Great deal:)

Jason
I bought the umbrellas through Cat but depending on the dealer you buy them from they may have their dealership name on them. I had my parts man do a Cat back-order, which brings it from a depot in this case it was from the paving division in Minnesota. The umbrella only has caterpillar on it, but I have seen some that say caterpillar diesel power. I'm still looking for the part number when I find it I'll post the number.

Found the part number for the umbrella it is #187-6649 cost is around $86.00
Tom