You can actually still have finance if you are bankrupt - but only if the lender is aware and if it is for a necessary reason.
If you have any equity in your vehicle (eg it is worth �10,000 and there is �3000 worth of finance) then you will certainly not be able to keep it.
If there is no equity (or even negative equity) then you may be allowed to keep it if you require it for work etc (eg you live in a village and there are no buses etc)