I just inspected my pass side motor mount while it was out. Looked fine but upon closer inspection
it has a small tear in the rubber. Being the PIA changing those out I opted to just clean it up and fill
it with
https://www.lowes.com/pd/LOCTITE-Pl-Pack-10-oz-Black-Paintable-Caulk/1002441008.
It takes a while to fully cure, like a week or more.
Even if I was installing a brand new mount, I'd use this stuff to make it tougher.
Seems like mounts for the mk1 diesels just don't last long enough on their own.
Ever better is 3M windoweld (08609).
People use it to fix lots of rubber parts, works well to re-inforce mk1(bad designed) strut mounts
Fix door or hatch seal rubber while you're at it. Any left in the tube will go bad
Cleans up with 90% iso alcohol (helps for smoothing it over too)