Fitting replacement 3/4 rear wings (fenders) advice.

[Val]

I replaced the side chassis members, floor pans, firewalls and boot floor about eight years ago, its now time to tackle the outer parts of the body! The front half is pretty good, having had new nose, wings and supports at some point in the past, however, the rear is not so good. I have rust in the rear panel and both rear wheel arches.

My intention is to strip all of the outside back to bare metal this autumn and cut out all the rust. I see that the rear wings are available as 3/4 panels and I would like some advice on the fitting of them from anybody who has done this. The new panels appear to stop about an inch above the body line crease. How did you join this? Lap the new panel under the old or butt join? If Butting, did you do it above or below the mould line? Any advice on this would be great, especially if you've got any photos of the process. I'm not 100% sure that I need to replace so much, I'll know more when I get the paint off, but I suspect that new 3/4 wings and outer inner arches will be the better job. It's just that long straight join at such a visible point that is bothering me!

[114015]

Butt join - seamless join (blunt end).

Below the belt line.

Here a pic from a fellow owner (Ulli).
He had gotten it above the belt line
but I think it is more recommendable to weld this below the belt line.

Good luck!


Achim

[Val]

Thanks very much Achim, you've confirmed what I thought.

Can you tell me what the thickness or gauge is of the original sheet metal? Also, what do you think is best for the wheel arch lip joint with the inner wing? I'm actually wondering if using a panel bonding adhesive might make the joint less likely to rust again. Any thoughts?

Thanks

[Shvegel]

I second the butt weld comment.  lap seams tend to catch water at the lap causing further issues and the seam is visible from inside the boot so the cleaner looking the better. 

When I worked in a body shop years ago we used these clamps:  http://www.eastwood.com/intergrip-panel-clamps-set-of-4.html

As an former body man and early adopter of panel bonding (I used to patch the floors of my cars with windshield adhesive urethane and sheet metal 30 years ago.  No We didn't have MOT where I grew up.)  My worry would be that if the panels are not prepped meticulously and with the best epoxy primers rust could creep into the interface of the steel and primer and release the bond.

[Benz Dr.]

My body man uses panel adhesive in places where you have two dissimilar metals or where heat can cause distortion or rusting at a later date. He also butt welds using a very small torch. This method uses no filler rod and he fuses the base metal of the two panels together with heat. Done properly, he uses no body filler on the seam and the under side is hardly visible.

PJ is having his car done there right now. It looks like something that rolled out of the factory even though the whole car had new panels installed.

[dirkbalter]

Val,
Among other panels I also replaces both rear ¾ fenders. It sounds that you are doing it yourself. I buttwelded the panels and agree with above statements. If you are welding, it is important to control the heat to avoid warping of the panels. I was told and it worked well for me to only weld small pieces and move around the length of the panel. (About ¾ to 1 inch at a time and cool them down with compressed air right after). It takes a while to get the whole panel done. Make sure you spend time to get the cut and the weld gap right.  I tried to keep as much from the original fender as possible, especially around the door jams to avoid any gap issues later. The replacement panels may not be as perfect as you would like them to be. I am happy with the outcome as they will only need very little body filler to create a perfect surface. I like the aluminum based metal to metal filler over standard body filler in these areas. I have been wrong before but I doubt that someone can change a ¾ fender without using any fillers, regardless if welded or fused, assuming the result is a perfectly flat original like surface.
Hope that helps
Dirk