Ben,

I'm not sure from your description if this customer is telling you he's not
paying, or if he's just trying to find a source of money for you and doesn't
have it all in one place. If there's any possibility he's honest and not
just trying to rip you off, you might approach him politely and tell him
he'll get the van back when he pays, no problem.

If the van is worth more than your bill, in fact you're the one who comes
out ahead if he defaults.

As others have suggested, get it it writing if you don't already. You also
might look into how the lien laws read in your area; you are probably
protected even if you don't have a form that restates them, but find out to
be sure.

I personally would understand making a partial payment beforehand if the job
required expensive new parts, as in heads. If mostly labor, I don't know.

If you think this is hard, try getting back rent from a tenant....

Good luck and keep the spirits up

Geza