When you drill it - you have to drill on low RPM s, otherwise you will get it hot and you will forge it. If it's already forged - get a carbide tipped drill bit from a store, it can long. Also, I got a kit, for drilling out and extraction of broken bolts, so I dropped a guide inside threaded hole to guide the drill bit, and drilled through the bolt, after got another size drill bit and drilled it through. Tried to retap it but broke the tap and decided to use m10 1.5 bolt and tap. It worked, but I had to get rid of huge amount of bolt clamp material and screw the bolt harder than m6, but I found kits that are built for this engine repair for broken bolt, I'll send you the link. I would say that using repair kit is better, you don't need to drill out injector clamp, www.amazon.com/dp/B006YDQ812/ref=cm_sw_r_cp_apa_fabc_GJ63WBH84RZ52Z97RSB5?_encoding=UTF8&psc=1 this is that I used to try extraction. www.amazon.com/dp/B075TFM9VN/ref=cm_sw_r_cp_apa_fabc_S1YRGS4WRQ7R3YAJNGNX this I would like to have when it happened.
Use cutting oil while drilling. If you don't know how to drill, watch couple videos on youtube and do couple practice test. No high RPM s. Only low RPM .
Same thing happened to me. Retapped with M8 Time Sert.
How did you drill the old bolt out? I try to do it but im not taking any material off.
When you drill it - you have to drill on low RPM s, otherwise you will get it hot and you will forge it. If it's already forged - get a carbide tipped drill bit from a store, it can long. Also, I got a kit, for drilling out and extraction of broken bolts, so I dropped a guide inside threaded hole to guide the drill bit, and drilled through the bolt, after got another size drill bit and drilled it through. Tried to retap it but broke the tap and decided to use m10 1.5 bolt and tap. It worked, but I had to get rid of huge amount of bolt clamp material and screw the bolt harder than m6, but I found kits that are built for this engine repair for broken bolt, I'll send you the link. I would say that using repair kit is better, you don't need to drill out injector clamp, www.amazon.com/dp/B006YDQ812/ref=cm_sw_r_cp_apa_fabc_GJ63WBH84RZ52Z97RSB5?_encoding=UTF8&psc=1 this is that I used to try extraction. www.amazon.com/dp/B075TFM9VN/ref=cm_sw_r_cp_apa_fabc_S1YRGS4WRQ7R3YAJNGNX this I would like to have when it happened.
Make sure you do everything what you can to get left handed drill bit.
Use cutting oil while drilling. If you don't know how to drill, watch couple videos on youtube and do couple practice test. No high RPM s. Only low RPM .
Thanks a lot.
Look for Laser Tools 6958 Injector Clamping Bolt Thread Repair Kit - Mercedes Benz CDi - www.ebay.com/itm/175189714048?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=Dnm2AaYhQpK&sssrc=4429486&ssuid=HrQM_e5zTYm&var=&widget_ver=artemis&media=COPY
You would be better off fitting a Time Sert & strech bolt