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Discussion Starter #1
I have a 2006 CDI with 235K miles. I have owned it for about 3 years and put around 40K miles on it. I don't have any covers over the injector so I can keep and eye out for black death. Last week noticed carbon around injector #2. Spend all day yesterday getting the injector out. Got up this morning and decieded to pull all the remaining injectors and replace the seal and TTY injector bolts. Engine was cold but since the remaining injectors were not leaking I thought it would be ok. All the injectors came out no problem but the #5 TTY hold down bolt snapped off. I have the #5 injector hold down bolt sheared off down in the hole.

Any ideas? Maybe call in a bolt removal specialist?

Right now I am thinking I will need to pull the head. I currently maintain 3 of these cars all the same (mine, wifes, and daughters). I just got down pulling the head to fix a broken glow plug on my car and now I have a broken off injector hold down bolt. I guess the good news is I have experience pulling the head so I know how to do it.
 

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I have a 2006 CDI with 235K miles. I have owned it for about 3 years and put around 40K miles on it. I don't have any covers over the injector so I can keep and eye out for black death. Last week noticed carbon around injector #2. Spend all day yesterday getting the injector out. Got up this morning and decieded to pull all the remaining injectors and replace the seal and TTY injector bolts. Engine was cold but since the remaining injectors were not leaking I thought it would be ok. All the injectors came out no problem but the #5 TTY hold down bolt snapped off. I have the #5 injector hold down bolt sheared off down in the hole.

Any ideas? Maybe call in a bolt removal specialist?

Right now I am thinking I will need to pull the head. I currently maintain 3 of these cars all the same (mine, wifes, and daughters). I just got down pulling the head to fix a broken glow plug on my car and now I have a broken off injector hold down bolt. I guess the good news is I have experience pulling the head so I know how to do it.
Take some closeup pix. Typically once bolt looses tension remaining stub is "easy" to remove.

Difficult part is to make perfectly centered punch mark. Starting with 1 mm drill make pilot hole. Switch to 2.5 mm left hand drill bit. If it bites good bolt will come out.

Avoid carbide drill bits. They snap off really easy. HSS drill bits only.
 

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How deep is the bolt broken off in the head?? Do you have a welder??

There's a video by Deboss garage on using a welder and a 12v battery to help get a bolt out of a head without removing the head. I've use that trick before, and it works.

 

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Ultimate handyman on the video has special guides for starting and that is important.
I have never seen them available, but even manufacturing one is worth it.
When you have no skills to manufacture, better leave it to professionals.
Also try if you can find industrial strength, left- twisted drill bits
 

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I have a set that helped a lot. Worked well on my bike exhaust manifold stud. This works if you have few millimeters of thread
to catch
 

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Discussion Starter #8
I am currently on travel and won't get home until Friday. I'll take some pics when I get back, the bolt is way down in a small hole. The bolt is probably 4" long and the first 2" of the hole are not threaded which is where it sheared off.

Late yesterday I noticed something and could use some help on. I have removed all the return lines and put them to the side. I am working on the car and its maybe 2' outside the garage door so I have plenty of room to work. To push the car back in at the end of the day I go in and turn the car on, put it in neutral, and push the car into the garage. In the morning I do it all over again and push the car back out. Turns out, in order to put the car in neutral you have to turn the key to the 2nd position and fuel will start pouring out of the injector return lines, it took me a while to figure that out and what a mess it made. My problem is the garage is not long enough to have enough room on the front of the car and I need to push it out when I work on it and then push in when done. Can anybody tell me what fuse operates the fuel pump so I can push out and in without pissing diesel all over the place.

I live in central California which is about 2 1/2 hours from LA. There are plenty of bolt removal specialist in LA but not many where I live. Still looking into that option. Still thinking about pulling the head. After my glow plug issue caused me to pull the head I know I can do it and the car probably needs the intake manifold cleaned out. With 235K miles I am sure it is probably pretty clogged up. These are really great cars except for three things, the injector seals, the glow plugs, and the sensotronic break computer module. I have now experienced all three.

Another thing I noticed, I had done the #6 injector when I first bought the car so it was still fresh but I decided to pull it out with the rest of them on Sunday. I had coated that injector with never seize when I did the repair. On Saturday night when I put the car in the garage I turned on the ignition to get to neutral to push it inside not knowing the return lines would be pouring out diesel fuel (only 2 return lines were disconnected). Bottom line the injector area got filled up with diesel. The next day when I took out the #6 injector the diesel had diluted the never seize and it all melted and went to the bottom of the cavity. I don't think using never seize on the injectors is a good idea. Bad news for me is I coated all the injectors on the rebuild I just did with the copper never seize. The bolt kit I got for the injectors has a silicone grease so that may hold up better. When diesel leaks it fills up the area around the injector all the way down to the copper washer. Has anybody thought about sealing the top of the injector with silicone RTV so nothing can get down around the injector?
 

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Can you put the rear wheels onto dollies to move it around?? That would take away the necessity to put the vehicle into neutral.

As I recall, the grease for the injectors is a ceramic grease.
 

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In aerospace we make guide blocks which clamp to the structure(head) and then you utilize a drill bushing. You can center it within a few thousands with your eye. There are stoveburn bits and others. Good A&P mechanic can pull a hole, but doing a center punch and handdrilling you won't get it perpendicular or centered. They almost always use some clamp blocks and have an assortment of drill bushings so they can step up the hole slowly. So for glow plugs for example, you can buy a drill guide which fits the counterbored area tightly.

I would think you could fabricate something fairly easily between Mcmastercarr and Home depot.

Michael
 

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For moving the car, you can unplug priming pump by the fuse, or directly under the seat, or switch the car to N and disconnect the battery, with key in.
The 2nd can be risky as I heard the key rolling code can be lost, but I did it on my W212 and no problem.
 

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Discussion Starter #12
I have attached some pictures which should help with anyone that is not familiar. The top portion of the hole is .308" and the threads at the bottom are for a 6MM bolt which is a little less than a .25" hole. Some of the pics are from a head removed from the vehicle which gives you an idea of what is below the valve cover.

I have been looking into how to drill out the broken part of the bolt. Its pretty deep in the hole so it won't be easy. I was looking for drill bushing and there are none that would work. I could purchase some stock and try to find a machine shop to make me one. The problem is I am still not sure how well this would work, the holes seem to be full of junk so not sure if remaining part of bolt will just spin out or if its sort locked tight in place. I will try drilling on one of the bolts today to see how hard or easy that is.

Another option is to use Time-Serts. Has anyone used a kit like that for the hold down bolt repair? I attached the info below but could not attach the picture. According to the literature below it says the hole for the tap must be .315" which is slightly over-sized to the max hole (un-threaded portion of the hole). The bottom part of the hole is .230" so the repair drill (.315) would technically remove all of the 6mm bolt. Has anybody done this? Is it that simple, the existing top portion of the hole would act as a guide to keeping things straight? I think it happens to the 5 cyl sprinter engine all the time. This would be a no brainer for stripped out threads but there is no mention of a repair for a sheared off bolt in the hole.

$110.50
M6x1.0, M6X1, M6 TIME-SERT Extended Thread Repair Kit
Also known as Mercedes Injector Bolt Thread Repair Kit
Diameter of Insert: 6mm
Pitch of Insert: 1.0 Coarse Thread
Overall length of included inserts: 17.0mm
Kit Contains the following:
6" Extension Drill
4" Tap
4" Installation Driver
(5) Carbon Steel Inserts 17mm long, Insert TS16107
Time-Sert Kit # 1610E2
*This tooling has no counterbore. The hole must be at least 8mm or .315 inches for the tap to access the hole. This kit is typically used in Mercedes injector clamp bolt thread repair and Dodge sprinter stripped injector hold down clamp bolt thread repair.
*Time-Sert inserts are always identified by the interior thread diameter and pitch of the insert.*
Made in the USA, the Time-Sert brand is recommended by leading automotive manufacturers
 

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I would find a good non-autmotive machine shop. They deal with these things on expensive parts. Might be able to find someone local to EDM the broken bolt out. Drill bushings exist. I would personally utilize a piece of flat Aluminum and center up with a drill bushing. Bolt it down, touch with a 5.5 mm bit to get a start. Then go to something smaller and use a drill stop. Then step the hole size.
 

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I would find a good non-autmotive machine shop. They deal with these things on expensive parts. Might be able to find someone local to EDM the broken bolt out. Drill bushings exist. I would personally utilize a piece of flat Aluminum and center up with a drill bushing. Bolt it down, touch with a 5.5 mm bit to get a start. Then go to something smaller and use a drill stop. Then step the hole size.
I"d use a steel bushing from experience. The aluminum ones cut really easily with the side of a drill bit throwing your center off. I dont' think you want to cut the aluminum threads.

If taking to a machine show, find a shop that specializes in tap breaking and use EDM machines. There's not pressure and no metal to metal contact during drilling, and so, no risk of damage to threads.

Take it out if at all possible and don't use an insert.
 

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I guess I didn't state that previous posting well. You use a piece of aluminum to HOLD the steel drill bushing. The Idea is with the bushing removed or you can make shift a point to center perfectly on the hole(to drill) and clamp it hard with bolts at 2 other injectors or if the head is off, you have many options.
 

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Discussion Starter #17
Just to help finish out this thread. I ended up giving up on trying to get the broken hold down bolt piece out. I tried to make a drill insert but could never get the center hole straight so I gave up. A machine shop wanted to much which is another reason why I gave up. Instead I went with a M8 x 1.25 time sert in the top of the mound. When I put the valve cover on and after installing the injector a normal hex head bolt would not fit since the hole is too close to the injector and you cannot get the bolt head to turn because it hits the injector. I had to order some grade 8 cap screws (allen head) in order to make it work. Since the threads are at the top of the mound there is no gap like the OEM design where the threads are at the bottom of the hole. Tighten the cap screw as best I could and after a short time it leaked so I tighten it again with the engine hot and got some extra on it. It lasted another couple of weeks with minor driving on it and then leaked again. This time I pulled the injector and put a new copper seal and the torqued it again all while it was hot. I think I got a good torque on it this time and so far so good. Now I have a injector hold down bolt with stripped thread. The injector actually blew out and the only thing holding it from going through the hood was the fuel line. It bent the fuel line up about 1” and fuel was going everywhere.

I ordered the 1610E2 time-sert kit since just the threads are stripped out. Its for 6MM threads where above repair was a 8MM insert since the bolt broke off in the threads and I couldn't get the broken piece out. Had to order a new fuel line too. While I am waiting on the part I am trying to figure out if I can do the repair with the valve cover on. Does anybody know? Can I drill out and then tap for the time sert insert without having to take the valve cover off is the question? If I have to take the valve cover off then all the other 5 injectors need to come out and since the engine is now cold who knows what will break. Best to work on these components when engine is hot.
 

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Discussion Starter #18
More bad news, they don't make the 1610E2 kit anymore and instead sell you the kit I already have which is for a 8MM x 1.25. No more installing 6MM inserts if or when the threads stip out, instead you have to install the 8MM insert and use a different bolt to tighten down with.

The bad news is in order to do the installation for a 8MM insert you need to remove the valve cover since the drill and tap are so much bigger . In order to remove the valve cover you have to take all the injectors back out. With the engine cold how many more fasteners do you think I will break.
 

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I have a short 10mm bolt holding in injector #1 on my CDI, its been holding pressure fine for the 4 years iv'e owned the car. ive had that injector out several times for other purposes, and it never fails to seal back up as long as the head is reamed flat and ive got a new crush washer in there.

An M8 bolt would work perfectly fine as long as you can insure the bolt is torqued down enough and that it wont back on in operation.
 
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