fixing hole in fender/rear quarter panel

[davem]

Hi there, I've owned my late model E30 for a few months. I've had to deal with all of the stupid leaks these cars have (replaced my taillight gaskets, adjusted the trunk latch, fixed the battery breather hose, got a new trunk seal) and I've finally narrowed down my last leak. Unfortunately it's not as easy of a fix:

I noticed water in the factory jack area whenever I drove in the rain. Looks like the seam between the rear drive-side fender and rear quarter panel and one other panel has failed on me.

The red arrow is the hole. You can see it from the bottom of the car, when I drove in the rain water was kicked up and ended up inside the trunk. I only found this hole when I stuck a wire where the pink arrow is. Water & sand got between the two body panels and therefore the wheel well had some rust (not too much). I tore off and peeled back some of the metal and now I have a bigger hole where the green arrow is.

I need to fix this somehow and am unsure how to proceed:
-initially i was going to clean up, por15, and use some fiberglass & bondo, then put some undercoating on
-now I'm not so sure, I know welding is the "right" way but I've never welded in my life and I could really use a quicker fix (if there is one)

Also I have checked the sunroof drains and the vents under the bumpers, they are not the cause of this leak.

[davem]

bump

[MaxBell]

Tailights were doing it for me. The foam gaskets are pretty hard and dried out after 24 years, they were leaking like crazy for me.

[davem]

Tailights were doing it for me. The foam gaskets are pretty hard and dried out after 24 years, they were leaking like crazy for me.

I don't mean to be an ass, but did you even read my post? My tail light gaskets are brand new, and they are fine.

I really need help with this problem as I do not want to pay hundreds of dollars in body shop fees to have it professionally done. I live in the pacific north west and therefore this car drives in the rain often.

[sweet88]

In no way am I saying this is the correct way to fix this. I had the same hole in the same spot. I had no way to weld it. I ended up spraying foam insulation in the hole, let it dry then cut off excess. I used brush on rubberized undercoating on both inside and out. That was a year ago and it seems to be working.

[AndrewBird]

Expanding spray foam is open cell and WILL hold water like a sponge. Not what you want.

Considering the hole is fairly small, the cheap quick fix would be to clean everything really well, then use seam sealer to fill the hole. Be sure to get it really clean though (I.E. - shinny metal) or the seam sealer won't stick. Then I would undercoat/paint to cover an bare exposed metal.

Seam sealer can be bought from your local auto paint supply store.

[sweet88]

I know what you are saying about the foam. There is no way to get it clean enough for sealer to stick. Several layers of the undercoating has worked so far. Belive me this is just a small part of my battles with rust on this car. I know it would be better to get rid of it and find a better one. For now I'm enjoying the challenge.

[zshopa]

i had the same problem, it was my sunroof drain, take a bucket of water and pour it over the sunroof, then seee the little tube in the trunk if that is leaking inside,

[davem]

Expanding spray foam is open cell and WILL hold water like a sponge. Not what you want.

Considering the hole is fairly small, the cheap quick fix would be to clean everything really well, then use seam sealer to fill the hole. Be sure to get it really clean though (I.E. - shinny metal) or the seam sealer won't stick. Then I would undercoat/paint to cover an bare exposed metal.

Seam sealer can be bought from your local auto paint supply store.

Yeah this is what I'm probably going to do; clean, paint, some sort of backing plate, seam sealer, heavy undercoat... even if I knew how to weld I don't think I'd be able to fix it well...too bad, car is really clean.

i had the same problem, it was my sunroof drain, take a bucket of water and pour it over the sunroof, then seee the little tube in the trunk if that is leaking inside,

Reading comprehension fail.

[davem]

Expanding spray foam is open cell and WILL hold water like a sponge. Not what you want.

Considering the hole is fairly small, the cheap quick fix would be to clean everything really well, then use seam sealer to fill the hole. Be sure to get it really clean though (I.E. - shinny metal) or the seam sealer won't stick. Then I would undercoat/paint to cover an bare exposed metal.

Seam sealer can be bought from your local auto paint supply store.

BTW do you mind expanding a bit on the sealer? We're talking like a urethane based seam sealer right?

[AndrewBird]

BTW do you mind expanding a bit on the sealer? We're talking like a urethane based seam sealer right?

To be honest, I'm not sure what it's made out of. If you just go into an automotive paint supply store and ask for seam sealer, they will get you what you need.

[davem]

I know its a dick move, but I'm bumping this in case there are any other options. It doesn't have to be a quick fix anymore. Shortly after I made this post I tried sealing it with fiber glass and spray can undercoating and of course it didn't work. Body shop quotes are also insane as far as welding goes...

Do I paint bare metal first? or seam seal bare metal and then paint, then undercoat? so confused haha

[KMOSES]

Use POR-15 and fiberglass mat (not the woven fiberglass cloth). POR-15 has a starter kit that has cleaner, metal prep. and POR-15 for around $30.
I have used POR-15 this way and it works great. Just follow these steps.
1-clean around the hole to bare metal 1-1 1/2 inches.
2-cut a patch three layers thick from the fiberglass mat that will fit the area you just cleaned.
3-clean the area to be repaired with marine clean that came in the kit, and follow the directions.
4-treat the area with the metal prep. that came in the kit, and follow the directions.
5-when the treated area is prepped and dry you are ready to use the POR-15. Make sure you follow the directions that came with the kit and use gloves, if you get this stuff on your skin it will not come off.
6-make sure the humidity is between 45-65%. POR-15 is a moisture cured urethane and to much humidity will make it cure too fast.
7-paint the area with POR-15 and wait about 30 min. to apply the patch material.
8-paint the three layers of the fiberglass patch you cut in step two with POR-15 and apply it to the area to be fixed. Use your brush press it into place. For the next 30 min. keep lightly pressing the patch into place until it stays put.
9-when the patch is tacky to the touch but does not transfer to your gloved finger, paint on one more light coat of POR-15.
10-wait 24 hrs. and coat the patched area with seam sealer

You hole is now sealed. I would also do this to the other side of the hole in the boot if you can get to it. Good luck.