New Zealand Datsun Club

I was wondering if anybody would have any tips for rust prevention on inner panel such as inside chassis rails, inner sills etc. Tips on what to use and method of application would be greatly appreciated!

Depending on what state the inside of these places is like now, I'd say squirt some rust converter in there to neutralise any corrosion present (As best as possible without opening the cavity up to access it) and then get in there with some cavity wax. The old school method was to fill a cars nooks and crannies with motor oil. But it'll weep out forever, and it's pretty gross.
There's a few brands of cavity wax on the market. But yeah, get it treated, and then keep the moisture off the steel. Poor old datto's had precious little protection inside places like that when they were built.

Ok cool thanks for the advice. From what I could see from having the sills etc off there is zero paint in these areas and some slight surface rust which made me wonder if trying to seal it would lead to the car carrying on rusting under whatever was sprayed on top. Have got some crc rust converter from town to put on and will try to track down the cavity wax, most probably will need to trip to Hamilton for that in a few weeks.

Thats the best you can do really.
If at the time of manufacture the panels has been degreased properly, had weld through primer applied to all the skins that were welded together, and were dealt to with cavity wax, there would still be thousands of them on our roads. Dirty old rust has been the death of so many.....

Examining a lot of old rustbuckets I reckon the biggest cause of rust is probably lack of drainage.

There are loads of large, flat bare steel areas on cars (insides of roof areas, undersides of floors etc) that don't seem to rust too badly and then there are all those closed off areas and joins that disintegrate in seconds despite being primed and painted (1200 cowl drains, 510 rear lower guards and under rear seats, where the rear guards meet the taillight panel etc).

I'd say pay close attention to water drainage and make sure you clear any leaves or debris that could sit there collecting moisture.

What John said.

240z especially have a couple of places where water pools and yeah, rust never sleeps.
i used odourless (insert Tui advert) Fisholene while the shell was on a rostisorie so it got in everywhere and dripped for days. Managed to drill a couple of holes from the cabin into the chassis rails and spray Fishholene in there via a long wand as rust loves those spots.

So if you can find a method which sprays whatever you use as it gets far better coverage and you can get a bendy wand into all sorts of places you can't imagine.

Thanks guys great tips, on my car a lot of the drain points appeared to blocked with rust

I agree with what has been posted and just add where ever possible clean out any dirt or dust that can hold water. And yes clean out any drain holes. Coat/paint any bare metal. Years ago I bought an import 910 coupe. I removed all the relevant trim and a panel beater sprayed inside all the cavities. That car never had any rust issues.

Good luck in what is essential preventative work for any Datsun owner

Hey guys, what rust converter product do you use, I have been using a crc brand but have found that on any areas that are bare metal it seems to get a covering of rust after a week or so that is much worse than any areas that are just left unpainted. I have used RustRoy in the past but it is no longer available to individuals due to health concerns but it worked great, did not have this happen. Had a look on trade me today and there is one called brunox that looks like it might be ok.

In the mean time my 1200 has a coating of the crc on the inner panels which leads to the question of what next? Do I spray more on to hopefully convert the rusty looking residue?

With the president there is some rust starting on the inside of the boot in the wheel well and the panel under the back window. The bit under the window has limited access through five holes and I have managed to scrape the paint off on affected areas that can be seen to expose the rust but don't want to have same troubles, so yeah, what should I use?