On 03/18/2018 03:33 PM, Nil wrote:
How can I fix this? the broken surfaces need to be strong against
pulling-apart forces, so I guess simple glue or tape won't cut it. I
was thinking of maybe drilling holes on each side and lacing the breaks
together with wire or plastic zip ties. Appearance is unimportant, as
this is underneath the car and not normally visible.

If there is anything solid behind the plastic push pins might work:

https://www.amazon.com/uxcell-50pcs-...dp/B00XP5KGYM/

There are a lot of different sizes but you'll be drilling you own holes
so find one that suits. The best type has a protruding stem that you
push in flush to lock the fastener. If you need to remove it, just push
it in further to release.