I replaced the perch using rivets as recommenced by Mercedes.
The rivets are rated at 2000 pounds shear. I figured that the load on the perch is about 4000 pounds when you factor in the lever arm created by the lower arm. So with 11 rivets there is about a five times safety factor. The metal under the old perch was solid. I first used phosphoric acid to treat the metal and then panted with epoxy primer. The rivets were dipped in epoxy before insertion.

The mess
[IMG][/IMG]

Cleaned up mess

[IMG][/IMG]

Epoxy applied
[IMG][/IMG]

Perch mounted

[IMG][/IMG]

Spring installed

[IMG][/IMG]