Help replacing Glow Plugs

Thanks for replying, no he hasn't, the top part seems to have broken off, he's not sure what to do. He must have pver tightened them. Any hints on getting the broken ones out?

No, they will be a real pain.I can only suggest tapping an easy-out into it and try that.But you dont want the tip of the glow plug to fall(or get knocked out) and drop into the cylinder.Then, you'll have a real problem.
Im guessing that its broken off flush and nothing is sticking up above the head?

i would say you are in big trouble ... if .... you go any further, if they have broken off at the base of the hex that the socket grips on to then the bit left willl only have a thin wall and if you use an easy-out you will expand the wall of it and lock it in even tighter...
There is a stud remover that uses a "spline" to grip on the sides of the hole you have drilled and you can work it backwards and forwards but you also may have problems even drilling it out as the core is not just metal, i think you will find ceramic in it also....
All in all it is not looking good for you.
I would not go any further and get a mechanic to at least look at it to see what your next step is, you may well end up having to take off the head.
Not good news for you but the glow plugs dont need to be very tight at all when you fit them ....
Good luck, i hope you "win"..

just noting you may find that they need to be tightened in "inch pounds" .......
Not going to explain that, you will find it on a "google"...

not a good scenario. take it to your mechanic , from my experiance as an apprentice, and having broken a rusted in one , i had to take the head off, sorry for the bad news

there are two of them, they are not completely sheared off, the thread is still sticking up, but they are not budging... I think we'll have to get a mechanic, or call the racq before we do more damage, thanks everyone.