I have a crack in my Sl 55 AMG's front air dam from bumping a curb stop. I would like to fix it with some glue from the inside.
What to use?

FOG

 

I have the same problem on my SL. On the TV show Wheeler Dealers (Wed nights here), they showed removing the bumper and spoiler, drilling holes on the back side about an inch out from the crack and inch apart and holding the part stationary with clamps and placing fiberglas sheets and hardener through out the area from the back side. Paint on hardner mix, lay down sheets, add more. Then when it hardens, sand off the little holes where the hardener eased through and touch up. I tried to repair mine with a small piece of aluminum belind and ss screws from the outside down each side after drilling pilot holes. I then touched up the screw heads. So far it is working but when you know it's there, it's there. (A farmer looking for his cow wouldn't notice). I don't know if the spoiler and bumper are all together or separate. Good luck.

 

drill some holes and use some plastic wire ties.

 

Turns out I have a problem with my headlights as well, the auto leveler isn't working so the bumper has to come off. So I get a chance to fix the crack properly, Now the headlights....that a different problem.

fog

 

I used bondo flexible bumper repair epoxy. It has been tested on a few parking bumps since the repair and is holding good. Here is a link to it at Autozone.

Bondo/1 oz. epoxy flexible bumper repair compound (806) | Body Repair and Accessories | AutoZone.com

I did take a little time to do it. Jacked up the car. It had been repaired before, so I took a dremel and cleaned out all the old stuff and beveled the edges of the crack (from the inside of course). Took some parchment paper from the kitchen and put it against the outside, then clamped a thing strip of wood against it to hold everything solid. This will hold it in place and make a nice smooth surface on the outside and the paper comes off clean. Mixed up the epoxy and put on liberally. After hardening, I took the dremel again and ground most of it off, just leaving the crack filled and a little extra. Then I mixed up another batch and put it on the crack again and spread it out a couple inches on each side. Then I cut and formed a piece of body repair metal screen and pushed it down into the epoxy and let it all harden. Figured doing it this way will strengthen it and spread any force out a little away from the crack. It looks like hell on the inside, but so far has been standing the test of time.
Hope this makes sense.
Good Luck
Rich

 

My Body guy told me about this stuff Fusior. It's specfically made to repair plastic bumpers, Sold only in Pro Body supply stores. for $41 a 2 tube pkg. of about 1/2 lb.
It's an epoxy type mix and works well It's real thick and can build up a complete tab (the headlights have extended tabs with threaded adjusters) with out a mold. Two of my tabs were broken badly I just greased the threaded adjuster and molded into the blob that I formed a new tab. when it hardened I was able to un screw the adjuster bolt and Wala! a new threaded tab, A second coat to further strengthen the thing and I ready to bolt the light back together.

FOG