Just got to replacing these falling apart strut mounts. Mechanic had never seen it like this before. Pictures are before and after.

 

That's what happens with the old style oem mounts... they disintegrate over time. And the rubber replacement ones ending up falling apart as well. I have had my car 13 years and replaced the mounts at least 4 times (and only 25k miles over those 13 years).. I JUST switched to the ones made by the forum member wayne and they are excellent and I do expect them to hold up longer than a few years

 

Yeah I recently went through the same thing and put it off longer than I should have. Whatever crap they used in the original mounts turns to dust over time.

 

Looks like you unfortunately went with the lousy URO shock mounts (the yellow color is a dead giveaway). After they fall apart in a year or less, contact forum member Wayne (cjd777) and snag a pair of his custom-designed ones. They are the best you will find (with plenty of research and testing behind them)....

 

URO supposedly upgraded the mounts they sell now.(darker foam material)
I have some WAYNE MOUNTS on my XK8 and some upgraded URO mounts on the two XKRs.

The race is on to see the 'time-test' results!!(I do keep the WAYNE MOUNTS in stock for me and my customers)