Sedan Rear Window Molding Bumper

[TonyE30]

Looking for a suitable replacement for rubber bumper on the inside of E30 sedan rear window air outlet molding (51131922331 and 51131922332). Mine manged to degrade/melt/rupture(?) in my hot garage over the course of past 2 years.

“good” example from web search on molding part
number:

My melted mess:


Are they some sort of fluid-filled bladder that popped? Or is a a rubber of some sort that simply degrades over time? It appears as if it were a butyl-filled rubber blister, sort of like a gusher candy.
want to make sure trim sits properly and doesn’t rattle on the freeway once I reinstall - 51131870459 clips and 51131904479 are proving expensive enough to not want to have to break/replace multiple times.

[Vincenze]

Can a weatherstrip rubber foam tape from Home Depot do the job? Tapes are available in different widths and thicknesses.

[TonyE30]

Can a weatherstrip rubber foam tape from Home Depot do the job? Tapes are available in different widths and thicknesses.

May need to go the weatherstripping route, I discussed with Bumper Specialties & Sorbothane - hard to find something that's low durometer and outdoor friendly - going to buy some samples but not finding anything great. Probably going to look at an automotive-grade product (likely from 3M) if I go the adhesive-backed foam route, learning that a high-quality acrylic adhesive is likely what I'm looking for.

[Vincenze]

May need to go the weatherstripping route, I discussed with Bumper Specialties & Sorbothane - hard to find something that's low durometer and outdoor friendly - going to buy some samples but not finding anything great. Probably going to look at an automotive-grade product (likely from 3M) if I go the adhesive-backed foam route, learning that a high-quality acrylic adhesive is likely what I'm looking for.

Could something like this work?

https://www.ebay.com/itm/389385621483

3M Products Window-Weld Sealer

https://www.summitracing.com/parts/tes-7100066530

[TonyE30]

Could something like this work?

yes that looks like a good option for material, but not thick enough - looks like the old ones are about 9mm "tall" uncompressed. I've ordered Sorbothane 0510134-30-10 & 0510134-50-10, we'll see if either of those ends up being the right fit of durometer and size. A little worried about swelling when wet, but got the urethane coated ones to hopefully help with water resistance.

[Vincenze]

Here's what an expert used. Neoprene foam.

[TonyE30]

Alright, here’s how it turned out. OEM foam, OEM clips and seals (looks like you can find cheap replicas from a few shops though), and the IsolateIT durometer 50 Shore OO sorbothane bumpers.

Will update in another 36 years to see how it holds up…

P.S. SEM Specialty Gel Adhesive Remover worked wonders getting off the dried up original foam and PSA.