14 replies to this topic

[therealtomgunn]

Hi All,

I'm currently restoring my '95 Cooper after it was stored under a cover for three years and picked up a fair bit of rust. I just wanted any opinions on whether my repairs will be alright. Basically the worst spots were the floor pan, along the doorstep, the passenger side A panel, the seams under the headlights, one spot on the boot lid, all along under the rear bumper, and th passenger side sill. None of it was really terrible and after chipping away until I got to healthy metal it turns out they were only small holes or surface rust, nothing strucurally worrying. The process I've used is to wire brush/sand down as much rust as I can, clean the whole area, paint on some rust eater paint, and fill in any holes with filler, rub down until smooth, primed and re sprayed. I've finished the floor pan completely and got to various other earlier stages with the rest of the car. The result looks and feels pretty solid and so much cleaner than when the floor was covered in rust and muck! So basically I just wanted to know whether this is the right idea and that when it comes to the dreaded MoT, I might stand a chance!

Cheers,
Tom

[Sam]

Without being unkind, it's really not the correct way to repair rust. You will probably find the rust will come back soon.

Any holes need to be cut out and welded. Filler should only be used for tidying repairs or filling dents - not for corrosion repairs.

[AVV IT]

In areas such as the floor pan and the sills using filler is a really bad idea. Whilst it might go through an MOT unnoticed, I certainly wouldn't want to be driving around in a car with holes in structurally significant places. A classic mini has poor impact protection as the best of times, one that's held together with filler is an utter death trap.

As for cosmetic areas like under the headlights, the issue is that the rust you can see is usually just "the tip of the iceberg". The corrosion tends to start in the seams between the panels, fueled by salt, dirt and moisture from the underside. By the time rust appears on the outer side, it's usually well set in beneath, in places that you cannot ever hope to reach with a wire brush. By treating and repainting the outer side, you are not addressing the underlying problem and can essentially make matters worst by sealing any moisture in, that will then speed the corrosion process further.

As mentioned above, you really need to cut out the corroded sections and weld in new metal, otherwise signs of corrosion will probably be back shortly after the next down pour, but if you're happy with that, then that's your call. In safety critical areas such as the floor pan and sills though, you MUST get these repaired properly, with new metal welded in.

[therealtomgunn]

Thanks for the feedback guys, I thought that these answers might come up! I'll inspect everything fully from now on to make sure all the rust is dealt with and that nothing remains hidden beneath the surface. I think I was just in denial at the thought of getting panels replaced/having to weld in new plates!

Cheers,
Tom

[bluesprite]

If you're planning on keeping it, then there's nothing to stop you doing it your way. You won't be the first and certainly won't be the last to do it like that. You've already said it's not a structural area and it's not like you're replacing a pillar with plywood.

'Small hole of rust in panel' here is viewed like there's a cross member or box section missing.

The rust under the headlight might come back if you use filler, but if it does you'll still only need the same panels you would need now anyway.

If you came to sell it with filler you couldn't say that those areas were repaired properly.

If it's a structural area it obviously should be metal.

[sonikk4]

To quote "its not structurally worrying" outer sill hole, fail, doorstep hole fail, floor hole fail. These are structural areas and if the MOT man suspects the use of filler he will fail the car.

If its only surface rust and holed then that will be ok. Unfortunately the seam rust although treated will come back. This is no way it will not.

Using filler as a temporary basis for surface rust is ok but i would not be spending money on a respray etc. Not worth it as it will come back. Any holes will need to be welded up especially in the areas at the start on my reply.

[bluesprite]

I know you shouldn't try to sneak things past an MOT inspector, but is it enough for them to 'suspect' surely they'd have to be sure. If it's a large patch of fibreglass/filler you could probably prove it with a magnet, but what if the MOT inspector fails a car that has been welded because he 'suspects' a body filler has been used. What if the filler just tidies up a weld, you'd have to strip back a potentially expensive paint job to prove him wrong..?

[sonikk4]

It does depend on the inspector to be honest. Gone are the days when they used a spike etc to probe suspicious areas. But if he saw what looked like filler in a critical area what would be stopping him from querying it.

There a few MOT inspectors on here and it would be good to see what they say.

[valve bounce]

There a few MOT inspectors on here and it would be good to see what they say.

at last i can be usefull

it is very difficult to fail a car if a rust hole has been filled especially if its a small hole (end of finger size say). the main reason beening that if you havnt seen the hole before hand.

but if there was a small hole in a sill caused by rust it would fail, but if you drill the hole out so its a purpose made hole it would be pass and advise.


basically if the hole had been filled prior to been presented for test it would be extremely difficult to fail as the tester wouldnt know there was ever a hole

[sonikk4]

There a few MOT inspectors on here and it would be good to see what they say.

at last i can be usefull

it is very difficult to fail a car if a rust hole has been filled especially if its a small hole (end of finger size say). the main reason beening that if you havnt seen the hole before hand.

but if there was a small hole in a sill caused by rust it would fail, but if you drill the hole out so its a purpose made hole it would be pass and advise.


basically if the hole had been filled prior to been presented for test it would be extremely difficult to fail as the tester wouldnt know there was ever a hole

Fair comment and from the horses mouth.

[AVV IT]

You won't be the first and certainly won't be the last to do it like that. You've already said it's not a structural area and it's not like you're replacing a pillar with plywood.

I must have misunderstood then, because the way I read it the OP stated that:

the worst spots were the floor pan, along the doorstep, the passenger side A panel, the seams under the headlights, one spot on the boot lid, all along under the rear bumper, and th passenger side sill.

....all of which I understand to be structurally significant.

The rust under the headlight might come back if you use filler, but if it does you'll still only need the same panels you would need now anyway.

....and I disagree. If you catch it early enough and cut out the rot in the bottom of the wing beneath the headlight, (where the seam folds over itself), then you can often get away with grinding any corrosion away from the lip on the front panel beneath and just welding a small section into the wing. If however you bodge the repair with filler and then paint over it, you run the risk of sealing in moisture and basically creating a veneer of filler for both panels to rot away behind. The end result being whole panels that will need replacing as opposed to just small sections of repair work.

Similarly if the corrosion is slightly more advanced, then cleaning up the front panel lip and just replacing the wings might be an option. Where as a bodged filler repair may well allow the rot to spread into the front panel as well, resulting in the need for a new front panel, which could have been avoided.

Edited by AVV IT, 02 April 2013 - 08:50 PM.

[therealtomgunn]

That's a lot to think about! Many thanks to you all for your advice and recommendations. I think a proper investigation into the extent of the rust is in order. Just to be clear with the floorpan, there wasn't a hole all the way through allowing me to see the ground underneath, the floor appeared to be double layered i.e. as if new metal has been welded on previously, and the top layer had a hole in it, revealing the layer beneath. It was this hole that I filled. I don't know whether this makes a difference (or if it even makes any sense to be honest!), I think I'll try and get some pictures on here tomorrow just so people can see exactly what's going on.

Cheers,
Tom

[sam-wkd]

Hi Tom, perhaps a plate has been welded on from underneath if you can't see the floor through the hole.

It would make sense to investigate it properly for your own peace of mind.

[CBJ805T]

Hi Tom, perhaps a plate has been welded on from underneath if you can't see the floor through the hole.

It would make sense to investigate it properly for your own peace of mind.

otherwise in a few months you'll find this:


or this (courtesy on an oversill!):

[therealtomgunn]

Gosh! Those photos are enough to make any grown man cry! Lol sorry you found that, I think a full inspection is the only answer. Thanks all

Tom