One of the studs on the bottom of the car that allows fastening of one underpanel broke off. Is there any fix for this?

 

hmm broken stud... generally, the broken stud has to be drilled out and sometimes body have to be re-threaded. what happened?

 

These studs are spot welded on.

I would perform the following:

1. Clean off both sides of the pan/base metal. Maybe an area about 3-4" in diameter.
2. Find a screw or bolt and grind the head down to about .08 to .10" in height.
3. Strip the plating off the bold.
4. Fit the head to the body (More Grinding)
5. Spot weld, gas weld, or tig weld around the new stud. Electric Spot Welding would be the best. Much less heat is exposed to the area.
Note: If you gas weld, I suggest some heat block materials to keep heat from burning the surrounding area. Tack weld small spots and let it cool between tacks.

 

^^^^^

 

It just popped off as I was tighteing after replacing the plastic underbody panel.

 

Those studs are a non-replacable items....Time to buy a whole new Porsche.

 

Nice advice.

Add:

Clean up welds with grinder as requried
Reapply rust inhibitive primer and undercoat

 

That is quite the pain in the behind for what is a rather flimsy stud. Get access on both sides (as required for the welding approach). Get an appropriately sized bolt (length and diameter), nut, fender washer (if you please) and some sealer. Drill small hole install items with sealer. If you ever feel like it it can be welded later on in the meantime its fixed and you can forget about it.

 

Well said. Thanks.

 

Another great idea.

 

That's true, but the problem is that now the car is worth half what it was last week and so can't afford to trade it in.