I have this rust on both sides by the windshield. The drivers fender needs replacing so that should be part of that fix, but is there a way to repair the other side with the fender on?

Thanks,
RickClick to view attachment

it rusted from the inside of the wheel and in the little seam covered with the 8" plastic strip. Take the wheel off and shine a bright light underneath. And remove the plastic strip and start poking to see how bad it is. IIRC poor or cracked seam sealer underneath harbored water and dirt for many years.

I have seen threads on the repair. They are out there.

As with any rust you need to go in and remove the affected metal and replace with new metal.

Basically you'll cut out the affected material after you have identified how far it goes, then weld in the new metal in patches. Its not an exceedingly difficult repair as its not structural, and is fairly open.

Usually at this point in the decay curve the penetration of salt and water has wormed its way into the cowl as well,allowing water to collect inside the cockpit and to the floor.
Surface scaling under the floor mats indicate the perforations above and require skilled repair or an Ontario crude "temporary"fix with a tube of silicone sealer.
Rust will continue to develop without the proper attention,and the rot is also more prevalent than a cursory inspection will reveal.
As far as I know the patch panels must be hand made and welded into a complicated intersection of four panels,as seen here many times.
Try searching cowl and fender repair,it's a good 4hr/side sum by pros,not where you want to learn the trade.
The correct way is to remove the fenders to grant full access,and the hrs are consequently greater when rot is found at the bottom of the inner fender.
Pulling up the frunk seal adjacent to the ex-puddles slightly and carefully in the corner may uncover a nasty hole in the corner that allows water to ingress the fuel tank well.
A long arduous journey on the trail of the water-rotter does have a reward at the end.

Welder required...

sorry to be so simplistic here, but its a common issue on the 356.

Cut out the rust
Make patch panels to fit the new rectangular hold you just created.
Weld in patch panel
Grind (all week)
bondo
Paint

Take a look at this thread for some potential insight, post #4

http://www.914world.com/bbs2/index.php?sho...eric%20%20build

Cutaway view

Jeff Hail and my thread both show step by step how to fix this.

I looks scary bbecause it is a complex joining of several weird shape panels but it only takes 20 hours to fix.

The restoration shop that repaired mine did the following. He cut the triangular piece out of the cowl. That gave him access to the rusty area. He removed the rust and welded in New metal. He then used metal adhesive to bond the triangular piece next to the fend e r a n d welded the triangular piece back in. Everything inside was cleaned and sealed.

Mike