It sounds as though when it was installed, the person may have overtightened the retaining nut for the electrical cable. This will spin the inner workings and cause the fatigue that broke the plug....Just a thought. No damage done.
The one thing I almost forgot. If the glow plug end was melted, it may need a new pre chamber. I've seen these worn over time.
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
[This message has been edited by Benzmac (edited 01-12-2000).]