Dinitrol 3125HS 500ML aerosol. Better than any underseal I've used before but pricey.
Dinitrol 3125HS 500ML aerosol. Better than any underseal I've used. A bit pricey but aerosol is convenient to use. Consistent in coverage, nice waxy dark brown finish and seems to last much better than waxoyl or thicker brush on types. Better value if bought in larger quantities for use with air spray equipment but this would be less convenient than the aerosol.
I've used this stuff on quite a few vehicles, the latest being my Defender 110 XS. It's ideal for spraying into box sections as well as the open rear cross member area. it will eventually dry to a slight tacky feel but will resist removal unless something like white spirit is used. The short extension nozzle is handy for covering specific areas without wasting the product on none essential items such as heavy suspension arms and struts which are ideally better painted. Any visible rust should be treated first with a rust converter product and then painted with a suitable chassis paint, you can then apply the 3215 spray. You obviously don't have that option for closed box sections but the product will reduce further corrosion in these areas.