rust problems

[sacvwgolf]

i found some (well alot) of rust round the petrol filler cap.





i was wondering what should i do? should i get a replacement panel and cut the rusty one out and weld in the new one- sounds like a lot of hard work- would have to take fuel tank out, or i should get something like this-
http://www.demon-tweeks.co.uk/products/ProductDetail.asp?cls=ROAD&pcode=MOCKCA007

seen a lot of Mk2s in PVW with this mod but it is expensive,

or pay the body shop to deal with it when they spray it?

[sharpie]

is that primer sprayed all over the place on the last photo? 

it depends how long you want it to last for, a whole new panel will stay rust free for the longest, whereas welding in new pieces won't last as long.

If it was me, I'd sand back the rust with some wet and dry and get it really smooth, if the rust has eatin into the metal then get it filled, before putting on some zinc primer and then painting it your car's colour. It won't last as long as the other options but it sure is cheaper, and try to keep an eye out for the rust before it gets too bad next time!!

If in doubt, get it taken to a body shop! 

[Agreeable Slick]

Either replace it or start looking for a new car.

Filling it won't do jack as the petrol will just eat through it, along with the vibration loosening it off, also from the picture it looks like it would need some fibreglassing to cover the hole and to give the filler something to bond too.

[sacvwgolf]

yeah i seen just the rectangle plate being sold somewhere.

[Thom89]

A complete waste of time and money doing anything other than cutting out the rot and "letting in" a new peice of second hand panel, it shouldnt take any more than a couple of hours work to get it to the point that it needs a skim of filler, especially if you know someone thats nifty with a MIG welder..
That area of the car goes rusty from behind, where sh!t from the road builds up, grinding it down to bodge it with any sort of filler makes no sense, unless you want to get shot of the car quick!
Tom

[sacvwgolf]

ok so what u saying is that it is better to cut the rust infected part out and replace it. i got a Mig welder so is it just a case of removing the fuel tank, cutting out the piece and weld in a new one?

[kkh120]

I did this very repair on my 91 8v. Got an angle grinder and cut out the relevent piece from a scraper and got a body shop to insert it and respray the quarter panel.

Cost me £140 but was a spanking good job.....at least I thought so!!!

[rubjonny]

before you do anything get underneath and have a good look at the inner arch, any rust holes here usually mean horrors lurking underneath the wheel arch!

[Thom89]

http:

ok so what u saying is that it is better to cut the rust infected part out and replace it. i got a Mig welder so is it just a case of removing the fuel tank, cutting out the piece and weld in a new one?

Yep thats about it.. no need to remove fuel tank, but thats entirely up to you!
This is how I would do it, remove the rubber boot that seals the outer panel to the filler neck, undo the small screw that holds the filler neck to the outer panel, and push the filler neck out of the way, as far as you can, with the filler cap securely "ON" you can wrap the neck and cap with a wet rag, just to make sure any sparks become harmless...remember, your welding the outside of the panel, not the inside..
Next job is to cut out your old panel, cut as close to the edge of the housing as possible, even if you have to cut through rust, this cutting is important to align your new panel, try and keep it accurate, drill a few in-line holes, so you can get a padsaw in to do the cutting, keep about 3mm off the edge of the filler cap panel all the way round.. what you should end up with is a rectangular hole, slightly bigger than the flap, then throw the old bit away!
Your new panel should have been cut about an inch larger all round than the one you just cut out, so you have more good metal to play with. Clean up your new panel, and rear 1/4 panel ready for welding.
Overlay new panel into freshly cut hole, reattach the filler neck to new panel to check that its going to realign.. once your happy, use a felt tip pen to scribe round the edge of your new panel, remove panel, and move filler neck out the way again..
Trim back your 1/4 panel to the scribed line, and make the new panel fit the hole exactly (no more than a 1mm gap!)
Tack (MIG) your new panel into place... take your time, weld 10mm, then cool it instantly with a cold damp rag, move to the opposite side on the panel, and repeat the process, cooling the panel minimises distortion
What you should end up with is a butt welded continuous joint that needs only a light touch with a grinder before a thin skim of filler, get it in primer as fast as poss, and seam seal the underside, before fitting the filler neck back into place
Hope this helps..
Tom



Mods , please delete this

[Thom89]

ok so what u saying is that it is better to cut the rust infected part out and replace it. i got a Mig welder so is it just a case of removing the fuel tank, cutting out the piece and weld in a new one?

Yep thats about it.. no need to remove fuel tank, but thats entirely up to you!
This is how I would do it, remove the rubber boot that seals the outer panel to the filler neck, undo the small screw that holds the filler neck to the outer panel, and push the filler neck out of the way, as far as you can, with the filler cap securely "ON" you can wrap the neck and cap with a wet rag, just to make sure any sparks become harmless...remember, your welding the outside of the panel, not the inside..
Next job is to cut out your old panel, cut as close to the edge of the housing as possible, even if you have to cut through rust, this cutting is important to align your new panel, try and keep it accurate, drill a few in-line holes, so you can get a padsaw in to do the cutting, keep about 3mm off the edge of the filler cap panel all the way round.. what you should end up with is a rectangular hole, slightly bigger than the flap, then throw the old bit away!
Your new panel should have been cut about an inch larger all round than the one you just cut out, so you have more good metal to play with. Clean up your new panel, and rear 1/4 panel ready for welding.
Overlay new panel into freshly cut hole, reattach the filler neck to new panel to check that its going to realign.. once your happy, use a felt tip pen to scribe round the edge of your new panel, remove panel, and move filler neck out the way again..
Trim back your 1/4 panel to the scribed line, and make the new panel fit the hole exactly (no more than a 1mm gap!)
Tack (MIG) your new panel into place... take your time, weld 10mm, then cool it instantly with a cold damp rag, move to the opposite side on the panel, and repeat the process, cooling the panel minimises distortion
What you should end up with is a butt welded continuous joint that needs only a light touch with a grinder before a thin skim of filler, get it in primer as fast as poss, and seam seal the underside, before fitting the filler neck back into place
Hope this helps..
Tom