I'm planning to get my 6 back on the road next summer and have been meaning to attack the underside for the last 2 years that it's been off the road. I suddenly find myself full of enthusiasm to begin the process and wondered what the consensus is from others who've 'done' the underside of their car.

I've read through lots of project threads generally and over the years, and have been spurred on by the clean, rust-free boot floor areas.
I see lots of shiny paint and I've decided I can't/won't go to that level, for a number of reasons:

The 'rust' is not structural (I came from a history of Minis before French hatches and nothing on a 306 compares), it is surface rust to my knowledge.

My car is not a show queen, it will get filthy in no time so paint is pointless and may become chipped.

It's too much effort.

I don't have the time or money.



So I'm planning to use Waxoyl underbody seal, like the good old Mini days. My main area of attack is the boot floor, which seems less well protected from the factory than the central undercarriage (Peugeot seem to have put a seal all down the middle, but not under the boot).

The idea is that I don't want an MOT failure in a few years for corrosion. I'm done with that. I won't entertain noticeable corrosion on a car anymore. It's a deal breaker. Some Rallyes seem incredibly rusty these days and it scares me. Prevention is better than the cure, and all that. I bought my car when it was 7 years old and at 14 now, it's time to take action I feel.

My plan of action, being woefully under educated in bodywork preparation and rust prevention, is to drill/wire wheel any surface rust from the boot floor, clean the area and then paint the underseal on.
Can anyone counter this programme with a better method or offer any nuggets of wisdom for me to abide by along the way?

I may even take some photographs and begin a project thread, perish the thought...

You'll see my thread where I've done this to my Rallye.

I would recommend cleaning the muck off the underneath with some truck wash or similar before wire wheeling. I found a Dremel with the small stainless brushes is good to get into tight areas where the wire wheel won't reach, though the little brushes don't last too long. I'd probably go with wire wheels on an angle grinder rather than cordless electric drill, as it will speed up the job a lot.

For long term protection I would recommend scuffing up the bare metal and painting with a zinc primer (most of the underneath was galvanised from the factory). You can either paint over that with stone chip or enamel for an additional layer of protection, or apply clear wax directly over the zinc primer.

Getting the surface rust off is what takes time. Painting it is much quicker and more enjoyable. I painted mine over a year ago and there are no chips to speak of. The clear wax gives a degree of impact protection.

I'd recommend Dinitrol or Bilt Hamber products over Waxoyl. More modern technology and do not dry out as quickly. I used B-H and am very happy with it.

I'd also get some wax into the chassis rails and sills - you can buy lances from the wax supplier that do this well, and I found it is not that difficult if you think it through, especially given what people charge to do it for you.

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Cherry Rallye SOLD

I also recommend Bilt Hamber products, it's worth buying a bottle of deox gel to smear over rusty areas, leave a few hours then wash off to get rid of more rust. (I sometimes put cling film over to stop it drying out if leaving it overnight).

Once the rust is gone i usually apply a couple of layers of Bilt Hamber Hydrate 80 before painting it.

I'm hoping to do the underside of my cars at some point now that i have a garage to work in and live half a mile from work.

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Goldie the track car.

I took it back to metal, deox gel where I couldn't get to the rust. Then Rust bullet over everything, red oxide primer and then hammerite for metal in red (car is diablo) which I applied with a brush. It is rock hard! As I can prove from hitting it with tools etc when fitting other parts

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205 GTi Red - G939 RTU - Died!
306 GTi 6 Diablo - Being resurrected! Project Thread

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