I came across a running and safe Ford F 900 at auction that was a water truck (tank now removed) and want to convert to flat bed to haul a ford 550 excavator. Any experiences with that conversion and how safe is that if not factory flatbed. Looking for WA state/puget sound contact that could help with that conversion.
Can you clarify your intent a little? Are you planning to scratch build a flatbed? I'm a little confused by your "factory flatbed" reference. Also, is the Ford 550 a tractor/loader/backhoe? That's what's coming up for me on a Google search. Loading/unloading the machine is going to be the biggest issue in my eyes, my recommendation is either a beaver tail flatbed with ramps or a rollback deck.
I can't buy the steel to build a flatbed, for less than what I can buy a used flatbed. To say nothing of the time to build it. So I would start scouring marketplace/ craigslist/ truck scrap yard, for a used flatbed or rollback bed. Last 20' flatbed (used) I bought cost me $1,500. You'll still need to be able to weld in some mounts and install u-bolts. And wire (lights) it up. If you get to the truck scrapyard, keep your eyes open for a set of 22.5 rims, because eventually you'll want to change over from the 20" multipiece rims that are on the truck right now. Like steve says, a beaver tail and ramps, or rollback. You're going to need to pay attention to overall height if its a backhoe, to either have a hole to put the bucket into in between the ramps on the beavertail, or get low enough on a rollback by stretching it out.
OK, it appears to be a WSDOT truck. More than likely it was hauling calcium chloride for ice melt. I would be suspicious about frame rot and everything else that is associated with salt. Snoqualmie and Stevens had several L Series Fords running during the winter and the tanks were in pretty bad shape when they were retired.Probably why there isn't a tank on it.
We had one much newer than that 10+ years ago and parts were hard then, I am sure they have not gotten better on that old thing.