Rust proofing the underbody and the inner body

I plan to rust-proof the underbody and possibly the inner body of my Jimny, while the vehicle is still young and with very little corrosion which can be cleaned with little effort.

The vehicle has no corrosion whatsoever in the trunk floor, nor anywhere in the floor below the front or the rear seats.
The outer underbody side has started to corrode in a few places, mainly near the coil spring mounting points, near the body mounting points and on a few other places where the factory welds are.


Now, I would like to hear additional opinions on some of my ideas and doubts:


1.

Would there be any point in spraying the floor from the inner side (for example below the rear seats and the trunk floor) with some anticorrosive protective layer?

I know that these parts of the body are usually first and most affected by rust in Jimnys. However, I personally think that these areas do not rust because they are "attacked" from the inside of the cabin, but from the outside (from under the vehicle). Somebody correct me if I am wrong!

So, in my (current) opinion, the floor of the vehicle should be well protected / rust-proofed only from the outer (lower / underbody) side, and there is no need at all to spray the body floor from the inner side. Am I correct?


2.

Continuing onto the first issue, I consider the area of the body floor which is usually most endangered by rust to be the one above the fuel tank and above the exhaust muffler.
So, wouldn't it pay off to demount the fuel tank entirely (because it is the largest "obstacle") and then gain proper access to the body floor from under the vehicle in order to fully and properly spray it?
Has anyone done this for rust-proofing purposes? If they did, was the removal of the fuel tank sufficient to gain good access to the entire rear part of the body, or should the transfer case and rear exhaust muffler be removed as well?


3.

I intend to spray the interior of the chassis rails and tubes with automotive wax (if there is a better material than wax, please advise).

However, would it make sense to (somehow) rinse the interiors of the chassis tubes first? I am afraid that rinsing them with high pressure water jets would be counter productive - while it might evict some dirt out, it would take a long time to dry the interiors of the chassis rails, possibly starting the corrosion inside before applying the wax.
Has anyone done this?


4.

I know that many Jimnys develop rust just below/behind the front head lamps. However, I do not understand why this happens. I mean, no abrasive particles or substances usually reach that place (as far as I know!), so the factory paint in that place should hold the bare metal properly sealed forever.
Does anyone have a clue why this happens?
And, what rust proofing agent to apply to permanently protect this area from future rusting?


5.

I intend to spray the inner cavities in all doors with automotive wax, as well to spray the exterior body panel sections which are usually hidden below the side plastic moldings (above the wheel arches and on the lower portion of side doors, etc.). Is there anything better than automotive wax for this purpose?

1. - no point in spraying the inside

2. - removing the fuel tank is a bit unecessary, the rust tends to be around the edges, sills and footwells. following the procedure to do a body lift (unbolting and jacking it up) would give much better access to everything.

3. - clean the chassis tubes with compressed air and a vaccum cleaner with a long hose. you are only aiming to remove any loose debris or flakes of rust.

4. - water gets in behind the headlights and pools there, as well as plastic trims underneath the wheel arch causing dirt trapping.

5. - the inside of doors, panels, etc is already primer painted but may be worth getting inside the sills with cavity wax as there are access points just inside the door if you peel the carpet back (rubber grommets blank the holes). I think there are some on the outside of the sills also but you need to remove the plastic trim to get at them.

Re what to use, I would reccomend Buzzweld ( www.buzzweld.co.uk ) who make a range of rust control, prevent and cavity stuff. Not badly priced and works really well.

At my job we are recommended to spray underbody with transparent wax first, let it dry, then go on with the thicker underbody sealer.
If I were to buy a new Jimny today i would fill all car with cavity wax everywhere i could, and lay down underbody sealer under. But the key to having a nice rust free car, is cleaning cleaning cleaning! and polishing! At least once a year I steam my cars under, remove all plastic covers and clean. Its the dirt and salt that kills all vehicles, i see it everyday at work. Those who take car of their cars dont have these problems

I put 20 litres of Waxoyl into my Jimny using just the cheapo Waxoyl presure sprayer and plenty of White Spirit to thin it down. It worked a treat but you and the car get absolutely caked in the stuff as does the floor.
Therefore get plenty of old cardboard boxes and lay them flat under the car, Raise the car up on axle stands or similar, clean off all the dirt you can, remove the front and back bumpers, grill etc and spray to your hearts content.
Take off all the inner panels as well and spray liberally everywhere!
Job Done and peachy perfect!!!!!

I don't know if you have already seen this thread:

www.bigjimny.com/index.php/forum?view=to...d=56816&limitstart=0

Quite a bit of rustproofing discussion.

I seem to go through this every now regularly and then when I get a used motor, Vitaras, Pinin, Freelander, Pajero, Junior and many others. Last one was my new Celerio which typical of Suzuki had no real protection underneath from new.
Interior floor surface I have only done when it has seemed to need it like the back floor of a Sherpa van that had been used by a plumber or the jack well in a Jimny. Such as these get a coat of something heavy and yes it takes a day or so to dry but when dry it is rock tough.
Always I do the box sections and that will include those holding seat brackets and the like. I drill holes in the sills if I need to and in some Suzukis the sill box sections are divided. Anything tube like gets it. lol
I always do the doors and such like. Either I take off the door card or find an ingress point. The injection tube is long enough to get along most of chassis sections doors and so on. I use Waxoyl with an airline
As for floor pans on the outside/underside once cleaned/derusted they get a coating. Wheel arch too.


Views differ on what to use but I use Hammerite underseal with added Waxoyl. Areas I cannot get a brush or spray to like between petrol tank and floor I will simply spray Waxoyl. I do hood (bonnet) much the same way, box sections inject panels underseal. As a bonus we get some sound deadening.
It's a long dirty job and I often wonder if I am wasting my time especially if I don't keep the vehicle.