For the 2nd time in my life I am the owner of a brilliant engine with a dubious wrapping. I've just bought an R Reg 4TRAK and I am now looking to slow the corrosion I can see/feel already taking hold of it.

1st area is under the sills rom the rear edge of the door toward the rear wheel arch. It's only showing through slightly but if you apply some force to the base of the sill you can feel corrosion which feels like it's coming from the inside out.

Is it possible/worth applying wax oil to the inside of the sills? Is there any other solution? Or is it better just waiting till it really takes hold in a couple of years, cutting the sills out and getting 2 new ones let in?

2nd area is where the rear arches join theboot floor pan. It seems like the panels are poorly welded and that water is migraing up the joint from underneath. Currently i'thinking the solution is to get to the seem from underneath and blather it with underseal. If I vcan get to it without removing the tank.

Also in this area - what is the filler that daihatsi use. Some small parts are coming out. I could botch it with harsd as nails or liquid steel but if I can get the right stuff I may do that.

All comments welcome

I know how you feel m8....the

I know how you feel m8....they do rot are a couple of suggestions.

1. Expose all areas where rot has taken hold...get rid of it by using a grinder till you have pure unadulterated clean bare metal..if you dont it will return. If the areas of rot are large then get em patch welded...if not too big use aluminium mesh and body filler.
Before patching/repairing treat exposed areas with anti rust treatment gel or the like.

2. Once all rust/rot has been removed and repaired paint it with POR 15...this is an amazing antirust paint from the states which really works. It can only be obtained from Frost Auto Restoration..go here to read about it...its not cheap but I gurantee the rust will not return if you use this stuff...which I have of course.

corrosion continued

Thanks for the info mike.

Will try the rust killer - what do you thiink about the idea of the sills rusting from the inside out??

If I squeeze them nr the rear arch I can hear the crunchy sound flaking rust makes and can feel some excessive flex in the sill - like it's thinned - but there is no bubling on the outside yet.



Yup your diagnosis is spot on

Yup your diagnosis is spot on Jim....the panels etc on these vehicles were galvanised in an effort to prevent rot...however where the panels are welded together water finds its way into the welds and rot sets in ...thta why most rot occurs around the welded seems...generally the chassis is fine and does not suffer the same fate as the body panels...if panels get scratched badly penetrating the galvanised surface of the panel this exposes enough of the metal for rust to start.
The worst places (especially on older cars)for rot to set in is rear arches where they are welded to rear floor section, at the back of the sills, rear floor section, fuel tanks cos mud,crap and water get trapped up behind the tank and it rots from the top down,the rear doors (dunno why). It has been written that the steel earlier models were manufactured from was poor quality.

As the other poster has written ..if you protect the underside with waxoyl from new you stand a far greater chance of preventing the rot from taking a grip ....if its already started I would deal with it now before it gets ant I suggested try to get rid of any accessible rot completely if at all possible by grinding/cutting it out..then repair by welding or filler if patches are small...give POR 15 a try I think you will be pleasantly suprised at its performance...word of warning...if you do decide to use this ant rust paint DO NOT get it on your skin...wear cloves and cannot be washed of with turps or have to wait till it wears off...I know this through bitter experience lol.

Just read your post again...dropping the tank is fairly easy....if you decide to do this you will be able to access the seam welds all around the back end...well worth doing if you intend keeping your trak for a while...some of the bolts that hold the tank guard on and the bolts that secure the actual tank can be bloody awkward due to rust..the heads of the bolts can round...machine mart do a great little socket set for removing damaged/rusted/rounded bolts...not cheap but worth their weight in gold I can tell you. If you have a manual it takes you through removing the tank step by step...took me a couple of hours to get mine out...glad I was pinholed all around the seam and on top...I used quick steel to repair and plug the holes...worked a treat and stopped all the leaking I had if I filled it over half way.


I spray my Sporty underside/box sections with wax oil every year. Dilute it with turpentine. Owned Sporty since 1992. Not a patch of rust!

corrosion continued

Hi Mace,

Had thought about this.
How well do you have to clean off the bottom beforehand - just all the loose stuff and the straight on to existing u/seal and bare metal wher u/seal has come away?