The U1300L is really easy to service. If you have the repair manuals, (mine comes with them) they detail all the rebuild/refurbish of each and every part. It's really designed to be serviced. Unlike the older round cabs, the cab on the SBU is designed to tilt without moving it forward or bolting anything on. You just take out 4 bolts in the floor, unclip 2 heater hoses from the plastic cradle. Hook on the cab tilt hinges (they should only ever been hooked on when tilting the cab, as the cab is torsen free mounted, same as the box), put your jack on the frame and mount on the bottom of the cab (special mounts for it), and start jacking. The only thing to be aware of, is when lowering the cab, to be sure to line up the steering wheel spines correctly. You can seriously tilt the cab in 20 minutes or less, being careful. If you've done it a few times, probably even quicker.
Furthermore, really, there isn't much need to tilt the cab. Fuel filters are right up front. The grill and hood come off in under a minute, using the hood key, and you have access to the entire front of the engine, hydraulic tank, air filter, etc
And, the dang things have so much ground clearance, you can just about sit up underneath them (you can, in certain area's) and work on it. These trucks were designed to be maintained by a farmer, in a field, with standard tools (with the exception of a mighty big torque wrench...or, as the door sticker says, a long pipe and a certain amount of weight on the breaker bar
)
With the cab tilted, you can access the entire engine, and transmission with ease.
Also, the transmission is divorced from the engine. It has a drive-shaft (small, prop shaft rather) connecting it. So, the clutch is really easy. No need to pull the transmission, just drop the prop-shaft, pull off the clutch housing (in my case, the Claas Overdrive), and voila! Clutch!
No wheel bearings to pack with grease either, the portals are oil bath.
Some of the parts are really common. The brake pads for instance are the same as some mid-80's sedan's. Many of the parts are Bosch components, air systems are Wabaco or Bosch. Brake hoses, belts, fuel filters, etc, all available with ease.
Besides Mercedes themselves (which I rarely buy parts from...) and Freightliner, there are some big parts vendors in the USofA.
Sean @ Eurotruck Importers is my main parts guy.
There's also Scott @ Expedition Imports and Jim Ince @ Eurotech services.
Sean @ Eurotruck sources the OEM for Mercedes, the guys whom supply Mercedes with the parts, so you can get the OEM parts, cheaper than the exact same Mercedes part, just without the blue box
Oh, and, there's a Unimog certifed technician in Edmonton. Well, two actually. One works at one of the mercedes dealerships, and the other is 15+ years working on mogs, and is freelance. Aside from that, any heavy truck shop or diesel shop worth their salt should be able to service the major systems (injection pump for instance, is standard Bosch) with the repair manuals.
Standard service is pretty easy. Oil filter is common (MANN or Hummel) about $11, engine holds 15liters of oil, treat it good, and it will treat you good.