I lifted my baby up and gave her undercarriage a good working over..
Day 1 Put her up on stands - that look a bit more scary than they actually were - once we got them supported in the right place..

Then steam cleaned the undercarriage.. and with a wire brush and a drill with one of those wire brush wheels removed all the surface rust of pretty much every square inch of metal.. including the diff, drive shaft, chassis members etc etc.. Them applied CRC Rust converter to pretty much any rust affected area.. I love how that stuff sets to a hard crust..
Day 2. Got to leave her on the heavier - more secure - lifters for the less messy job of paining..

Then applied 3 cans of CRC Zinc It.. Then 4 cans of Plasti Kote Matt Super.. for a top coat.. and then bitumen type under-seal to under guards and body etc..
Now my baby's bottom is as sharp as her upper side..
Also tightened a few loose brackets around the tanks etc..
A very rewarding couple of days work..

89 Nissan UD Bus 9mtr (Civilian) 6.9ltr FE6.. TYRES 7.5 x R18 Hankooks.