Common faults...
Rust, check out the lower 6 inches all around, the battery trays and cab door bottoms. Check the bottom of the windscreen for paint bubbles, same on rear door. Check chassis put riggers and all frame members carefully. Check the roof gutters and walk away if they are in poor shape.
Electricals:
Your bus will have a butchered loom some place! Make sure it looks neat and everything functions.
Ignition switches fail due to high current to starter solenoid, use a relay on this circuit. Fuse boxes turn brittle with age or may be wet due to leaking screen/rust. Horn may be intermittent due to earthing problem in the column.
Dynamo/alternators do fail. The wiring can be brittle due to heat/age and the crimp connectors fail.
Engine:
Make sure you have the oil bath filter if stock, not an aftermarket pancake type.
Ensure all cooling tin is present, especially the deflector plates under the cylinders. Look out for holes in the manifold heat risers.
Check end float!
Look for oil between box and engine, this could be the flywheel crank seal gone. Is the engine clean and loved or a mass of oily crud? Is the oil clean and up to the mark on the dipstick ?
Are the original rocker covers on, avoid chrome crap ones. Any strange noises, does it start easy and tick-over smooth. What is the dizzy ? Try to get stock engine unless it has some tasty tuned engine with all the right bits. Avoid something that has been thrown together from a spares bin.
Mechanical:
Pretty robust really. Ball joints ok? No splits in rubber? Same with CV joints. Is the suspension level side to side front to back ? Lookout for broken torsion bars. If lowered how? Does to look neat and tidy, clean welds etc..
Steering box play, not too sloppy.
Brakes, firm and pull up square ?
Interior:
Original is better, but if you are wanting to make your own/custom then this does not matter. Lookout for signed of leaks around windows and pop-top, check for rust again.
Make sure the m-code plate is there and tallies with the van. Ensure the chassis number is on the rear RHS frame just by the air filter stand.
Ask lots of questions!
Try and view in good light and lookout for botched repairs and filler!
Good luck!
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