(G) Rust in bottom of doors

I am putting my 84 Uno back on the road. It is fine but has some rust in the RF and RR door. From the outside the rust does not appear to go any further up than the first crease which is approx 25 mm up from the bottom edge. I am thinking of getting a very small skin bent up and slipping it up underneath, tacking it along the edge of the crease then sealing it with a rubberised spray on product on the inside of the door. Any comments anyone. I have never done panel repairs before.

Personally for the price of a new door, and the work involved in welding, filling and spraying the damaged ones you have, I'd go for new doors.

Incidentally the corrosion is caused by the outside window seal on the window shrinking, which leaves a gap at the front (near the mirror), or rear near the pillar. Water drips down from the window, and leaves the inside of the door wet, which then eventually rots the door from the inside.

New rubber seals, leaving no gaps will prevent the problem from occuring in the first place.

you will be better finding new doors mate!
i bought i uno around a month ago and the o/s rear door had been repaired and now its falling to bits from the inside out.

sy

Best way to fix it is to do what I always do. Bog it!!! When done with care this provides a perfectly good solution. Just use rust converting stuff (if you can make up a small trough to put it in thats better) It takes awhile to get rid of all the rust.

Once you have removed almost all of the rust, dry it carefully, then paint it with etch primer. This is a really good primer for preparing surfaces.

I also often use that rust converting paint on the inside of the door.

Now just fill and paint.

To help the repair last you should now fill the inside of the door with waterproof wax.

It is impossible to keep water out of the doors (even with new seals) so your best bet is to enable the water to flow through the door, so make sure the drain holes are clear.

I'm sorry to disagree. But the danger of sealing the inside of the damaged door with wax, or another sealant is the good chance of sealing in the rust, and moisture. Which would then lead to further corrosion.

The doors are designed to allow a little amount of water ingress. Dew, and rain water will of course always get inside the door. But with a good window seal, the amount of water is so little, that the water will evaporate quickly, or drain away.

In my experience, (and maybe this is because the UK is a particularly damp country), you can really never cure rust off a panel compeletely. Yes, you can set it back a few months, by working on it. But the only real fix is to replace the panel. Uno panels are so cheap now, that's the route I'd take.

The conflict between Circolo and jjhepburn arises here because we in NZ simply don't have access to new doors, cheap or otherwise This is because the rusting was much slower than in the UK and typically took at least 15 years to become a problem, so nobody bothered to stock replacement doors.

To fix properly (i.e. by welding) is actually quite difficult due to the thin-ness of the bottom lip and the risk of distortion to the large, flat door skin. Also the welding tends to leave tiny gaps that lead to more rust. Welding something over the top of rust is also a sure way to continue the rusting underneath - and, the repair will stand proud of the sill line, making it really obvious. On the other hand, welding on more steel tends to increase the strength of the door.

The bog approach, with some etch primer and/or rust converter, holds the rust at bay for at least a couple more years and ultimately, you have to be realistic about the life-span of the car and the cosmetic effect of a few rust bubbles.

If the doors are only mildly-bad, this is the approach I'd take. You can do a couple of bog-repairs (i.e. at least four years!) before the door becomes too much of a mess to work with or the rust endangers the strength of the door. When this point is reached, you should be able to find doors in wrecker's yards that, while not rust-free, are an improvement. Be careful of taking on someone else's inferior bog work, though Check for evidence of previous bogging - not everyone is as careful - 'pink' bog used straight over rust will not be very successful. Most panelbeaters still believe that filler only sticks to bare steel - this simply isn't the case and leads to faster rusting.

So, to clarify the steps of the best bog-job, use a really aggressive wire brush (e.g. a wire wheel on an angle-grinder) to clear out all the rust holes from the front, and the back where possible, including any previous filler. Dig out all the hardened seam sealer and rust flakes (most will just lift out with a screwdriver from inside the door). Better to remove more steel if it gets rid of more rust. If you can wire-brush everything to shiny steel, just use etch-primer at that point (otherwise, use some rust converter as mentioned). The white aerosol type of etch-primer seems to work really well for us. Then use fibre-reinforced bog (e.g. 'Newtech') to fill the now-primed rust holes and finally sand carefully with a long board, re-etch prime, and then fill with standard filler. Finish up with proper primer and paint, even inside the door, and you'll greatly slow down the rusting.

We found that 'Tergo' rust converter (organic white liquid that turns black) is a waste of time, seems to still allow rusting underneath, and that acid-based rust converters, while effective, need rinsing off with water - which tends to be a problem for obvious reasons! So I'm personally not very fond of rust converters any more, I prefer to remove as much rust as possible with a wire brush, and then etch-prime.

If you did manage to get rid of all the rust, there's no reason why such a repair shouldn't last for a number of years, which is a long time relative to the day or two that it takes to do the job.

To answer thepottleflump's question, to my knowledge, zinc primer does not corrode preferentially because it's not really electrically-bound to the steel (the organic components would interfere with that). Etch primer is basically a high-adhesion primer to ensure the steel is protected from moisture, and it seems to work.

-Alex

In NZ a new door cost more than the price of an old Uno most of the time. I priced up new doors for my uno turbo. If I ever had a mint Uno again and needed a door id buy new. If you have a $500 Uno then no need, just bog it or find a good used one.

I'm not sure if it's the same in NZ, but here in the UK 5 door Unos are rarer than 3 doors, and as the 5 doors have twice as many doors that means you're twice as likely to have a door go rusty on you

There are companies in the UK that sell Uno door skins (3 and 5 door), both as the lower section and the whole skin (from the window downwards). But as Alex pointed out, the biggest problem is that the metal is so thin and it's very hard to weld the doors without distortion occuring. It can be done if you are VERY patient and take your time.

To deal with rusty door bottoms, there is only two ways of banishing rust. One - replace the door ( ) or Two - cut all the rust out and replace it with fresh metal. Bodging it might keep rust at bay for a while, but unless all the rust is cut out it WILL come back.

Regarding anti-rust was (Waxoyl, Dinitrol etc.) they can both be very effective. Neither will STOP rust from spreading once it's occured, but they will slow down the spread of it. The best thing about anti-rust wax is that it stops water from staying in contact with the metal, and however good the seals are on the windows quite a bit of water WILL get into the door itself. Thus the wax helps it to get out again, assuming of course the drain holes are kept clear...

Of interest, the door seals on a three door Uno are apparently exactly the same as the Cinquecento so there's the opportunity to go and buy some new ones! And another trick that Alex mentioned once was to use the window seals from the inside of scrap doors as they suffer less from shrinkage than the seals on the outside. Probably because the outside get exposed to the elements and UV radiation whereas the inners don't.

BTW, when I got my good passenger door I covered the inside with anti-rust wax (after removing the original breaking up black tar wax). That was four years ago, and as of yet there's no rust to be seen

Thanks all for the time you took to give such full answers

In NZ, Mk1 5 door Uno's would be the most common by a huge margin. Mk2 3 door unos (turbo and 45) would be the least common.

I agree. Oddly enough I think the situation is reversed for the Stilo - 3-dr seems to be the biggest seller here, and not in the UK. Grande Punto is even stranger because the 3-dr is only available here with the diesel engine.

You stated that you could buy new Uno doors earlier in this thread - where, and how much? CCS? Are they genuine FIAT panels?
My enquiries on this drew a blank a couple of years ago.

Cheers
-Alex

3 door Punto is only avaiable as a diesel, but they are all diesels except the most basic 1.4 petrol model.

I think 3 and 5 door Stilo Abarth's are about the same, maybe a few more 3 doors. However all non Abarths are 5 door.

Doors were avaiable through ccs. Lee even got a couple of new skins in the old stock sale.

I have a few rust free mk1 '5 door' doors, nsf,nsr, and osf all in orangy red, key scratches/faded but otherwise perfect. Shame you aren't in UK tho!

with regards to the door seal rubbers, they can be bought new from fiat still, i purchased both the inner and outer rubbers for my new mk1 doors fitted to my black mk1.

i think they came to about 15 quid per seal so 60 quid for all 4.

That's not bad in price. And for piece of mind, particularly if you cure, and treat the insides of the door, as you replace the seal, it's money well spent.