Water pump bolt snapped

[jicaino]

JB weld could work if used the right way.
Also, I'd deal with this using a sleeve as other suggested. I also use threaded sleeves for some locations (chuck a grubscrew in the lathe, center drill it to the size of the long LH drillbit I'll use)
But I kind of second that comment of leaving it to a pro, especially since you want to avoid removing the timing cover.

Down here it's common practice to hire rethread/insert pros that would do the job on the site, when your skills/equipment aren't enough. They take care of extracting your broken bolt(s), dealing with thread repair if needed and such. Maybe you have some local guy working on that? Ask around mechanics or machine shops.

[wagons ho]

I'm surprised no one has responded with its time to do guides anyway.
Hey! It's time to do guides anyway so pull the front cover and do the timing guides. While you're there, take out the broken bolt.

[garner13]

Man I must say some of you guys are harsh, (but that is a good thing). I have been working on my beamer for over 20 years but this was the first time I had a bolt to break off where I can not reach it with my bolt extractor. I was able to find a tube today and I will try to remove it tomorrow. I was really trying to avoid spending 8 or more hours taking the timing cover off but if this do not work, I will do it.