See the page from the service manual I posted above. There are sintered bronze filters in the metal canisters they are pointing to. If they get clogged the hydrostatic system will make noise and it will be hard to make turns.
Maybe here
http://cuttingedgereplaceme-px.rtrk.com/
http://www.paumco.com/product_cuttingedge.html
Or if you have a way to drill the holes
http://www.onlinemetalstore.com/items/1055_Steel_Beveled_Cutting_Edge.cfm
All the Bobcat parts diagrams are online here.
http://www.bobcat.com/partsandservice/genuine_parts
You have to use Internet Explorer for the site to work.
Parts will likely be only available from the dealer.
Found another picture and I now see what you mean that the button is gone. Is it broke off or just stuck all the way down in the hole.
Again online parts shows it to be available.
There's supposed to be a inspection plug in the open hole in your picture.
The Bobcat online parts catalog says the plug is still available.
I think the fuel rack bottoms out on it.
The whole excess fuel lever seems to be missing. It's the white piece above the inspection plug in the picture below.
Will it move forward with any real force, with the bucket against a tree will it spin the tires?
You may just need to block it up in the air and cycle the drive system to purge some air.
Depending on how bad it is you could braze the cracks. I've done that many times on old tractors.
The Ford industrial 98 cid. engine was used in several different types of equipment(fork lifts, floor sweepers, large lawn mowers and skid steers) so finding a manifold shouldn't be too hard. Also...