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The way to avoid broken bolts is do it on hot engine.
One of the youtube movies show how the guy pulled 1 injector, fixed it, than took the car on drive again since the engine cooled and then do 2nd injector.
 

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Discussion Starter #22
I was able to find the 1610E2 6MM repair kit. The last one in the free world (ha ha). I did email the supplier and they said they discontinued because users were breaking off the drill / taps in the hole. Again the problem is if you have stripped out threads then you can repair them using the 1610E2 6MM kit and you don't even have to remove the valve cover. If you shear off the bolt then you should use the 5812D 8MM repair which is done at the top of the mound. The problem is the manufacture no longer sell the 1610E2 kit and instead says to use the 5812D 8MM repair kit. In order to use the 8MM repair kit you have to remove the valve cover. In order to remove the valve cover you have to remove all 6 injectors. Can't heat engine up because the #2 injector cannot be installed because there are no threads so the removal of the other 5 injector hold down bolts would have to be done with a cold engine. Good new is I found a 6MM repair kit.

I did the repair and put it all back together again, the hold down bolt torqued up nominally. 7 N/m and 2 90 degree turns without an issue.

Started engine and now I have a 2257-004 pre-glow plug code and the #1 injector is leaking. I will repair the #1 injector tomorrow and I plan on putting an insert in. Not sure why these injectors keep leaking, not sure if I am not cleaning the hole good enough or if its a torque problem. Going forward any time I take one out I will be putting an insert in. Attached are some pics of the repair
 

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Discussion Starter #23
I want to point out another problem when working on the injector hold bolt. The bolt is so close to the injector its hard to get the tool in. See attached pics, I ground down the 2nd pic so I get a better shot at the installation.

This is why the 8MM repair is touchy, can you imagine a larger bolt, very close to the injector. Have to use a cap screw and a long allen socket to torque it up.

Is there a special tool that your suppose to use
 

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Discussion Starter #25
So its been 2 months with no problems but I just checked the engine and the #5 injector is bubbling fuel up around the injector. The #5 injector is the one I had to install the 8mm insert so I am not using a 6MM bolt and instead just tighten it up and try to get as much on it as possible on it. I am afraid to use a 1/2" ratchet so I use a 3/8" ratchet and get it as tight as I can. I even torqued it on a hot engine. So that's twice now it has started leaking around 2 months after putting it together so something must be wrong. Either I am not getting the hole cleaned out good enough or I am not getting the bolt tight enough. I suspect I am just not getting the bolt tight enough since it works fine for a while and then starts leaking. Does anybody have any suggestions? Should I try using a 1/2" ratchet"
 

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Is the 8mm bolt stretch bolt too? System is designed to adjust heat expansion and keep the sufficient sealing force by 'spring bolt'.
Did you use ceramic grease on injector body? Sure both cylinder head bottom hole AND injector nozzle holder surfaces are nice and shiny?
Too bad one bolt seems to be slightly under dimensioned (BMW uses 2 bolt per injector AFAIK)
 

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There's a special kit by British company Laser tools 6958l - it has a guide to drill accurate, it has a depth limiter, it has everything. But I did use m10 1.5 bolt to fix the broken bolt issue.
When you got a new thread, you need to have Allen style bolt, grind away some head material to decrease diameter of the head of the bolt. The hole in the mount should be extra big size to give to bolt ability to move inside easy and change the angle. Also use a split lock washer. The torque for the bolt should be significantly increased. I used 3/8 wrench and gave a huge torque ( almost tried to snap threads)... Before I wasn't putting so much torque and my injector was moving...
My mount was drilled with bigger than bolt drill bit, after the size was increased with carbide head...
 

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Discussion Starter #28
I cleaned it up and put it back together yesterday. I did change a few things since you know what they say: insanity is doing the same thing over and over and expecting different results.

The bolt is an allen head and I lubricated the bolt with motor oil and torqued it to 35 Ft/lbs which is around the normal torque for an un-lubricated 8 x 1.25 mm bolt. I did notice the hold down clamp did not fit very well, the insert is a little off center and so the hold down clamp with the bolt is not perfect. I thought about that last night and may take it apart and open the hole in the clamp so it fits better. It did seem like once the bolt got started and partially threaded it lined up better.

I also thought about using a lock washer and after your suggestion will start using one going forward. The bolt is suppose to be grade 8 but I read the info on the kit (box with several lengths of 8 x 1.25 mm) and it was made in china. I may try to find some other bolts

So far the bolt is holding but me wife's commute is only 7 miles or so to work and it really never gets super hot. I need to take it on a longer test drive to see if it leaks. Will probably wait until I have a new bolt.
 

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Discussion Starter #29
Wanted to update, so far so good. Torque is holding, we have taken it on (3) trips that lasted 2 hour hours or more plus the daily driving with no leaks.

I do want to add one think since I had several fuel leaks during this whole thing. The diesel gets down into the injector holes and melts away the ceramic grease, I had it all over the place. I can tell you one thing for sure, I am not taking everything apart again to re-grease the injectors.
 
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