Underseal to a T3, well any motorhome really

I’ve just bought a T3 van, so I am obviously keen to look after it.

What is the best way to protect the underside.

A friend, who actually owns a similar van, says I should just buy a tin of underseal and paint the whole underneath of the vehicle. No doubt this is a messy job, but if it is necessary I'll do it.

Do I have to wire brush everywhere first ?

Another friend suggested red oxide primer paint, then a normal oil based paint.

What do campervan users recommend please ?

Many thanks for any input provided.

yup, pressure wash it, drive about on a hot dry day so its not even a teeny bit damp anywhere, then wire brush any loose stuff off and blast away with a shutz gun, waxy underseal is best..waxoyl is not that good but dinitrol etc are very good if a tad pricey.

Bottom of B pillars, the sills and inside box sections above the rear jacking point and in front of rear wheels WILL have rust inside. Doesn't matter how old or mileage of the van. It might look ok from the outside but believe me it won't be inside. I use a product called Vactan ( off ebay etc ) to treat the rust. I've just poured it into all the above mention areas on my South African T3. Then spray Dinitrol into them  Front B pillars can be accessed through the air vents in the door jams, rear areas can be accessed behind the trim on either side of the rear seat area. And this is just the start. . . . . . . . . . . . . .    .         .

Edited by TransPorscher - 26 Aug 11 at 23:25

Read the independant tests on Dinitrol, classic car mags reckon it`s the bollox

 the stuff ive used is like tar...  not the cheap stuff that halfrauds and the like sell..

Brickwerks did mine with Dinitrol.  It has stopped some of the existing rust in it's tracks, and will hopefully make the van live longer than otherwise would be the case.  Watching it being done I would not want to do it myself, let alone without a 2 post lift.  Well worth the investment I reckon!