Underbody sealer & rust prevention

mikeyboo wrote: »

As above I've a 04 transit recovery underbody was never painted r sealed, some parts underneath have paint,most of it is surface rust what is the best way to stop from rusting more and keeping it sealed. Can move if not in right section.

Bilt Hamber have a very good range of underbody protective coatings which are pretty specific depending on what parts you are wanting to protect, and then sealants.
If you have rust on a transit it may be terminal without investigating further.
You need to look inside chassis rails especially as many transits from that era have gone already from corrosion.
https://www.bilthamber.com/corrosion-protection-and-rust-treatments