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View Full Version : Well, looks like my ''good luck'' ended..


solera
03-11-2008, 07:36 PM
Pulled the cover, found a leak at the #1 injector.

Took to dealer,who managed to break off the hold down bolt in the head.

Now he wants to sell me a new head,, or truck.. bastards... :yell:

Is there a good way of extracting the remains of this bolt?

As I type this, he's with his mgr ''discussing the problem''

Anybody have any input??? ..

abittenbinder
03-11-2008, 07:51 PM
Model year and mileage? E-mail me your phone number. Doktor A

05highroof
03-11-2008, 07:59 PM
Doctor A to the rescue! Please keep us posted on your problem.Good luck!

solera
03-11-2008, 08:08 PM
Model year and mileage? E-mail me your phone number. Doktor A


Sent..........

Thanks Jim

solera
03-12-2008, 12:21 AM
Doctor A to the rescue! Please keep us posted on your problem.Good luck!


Went and looked, at the problem.

The bolt is broken 21 mill from the head.

Right where the threads start.....

Secured a budget rental van, to be able to work tomorrow.

the Good Doktor n' I,,,, are discussing it. :hmmm:

sikwan
03-12-2008, 01:01 AM
Best of luck to you too. Keep us posted.

abittenbinder
03-12-2008, 03:17 AM
Here is the #1 injector bore and its hold down bolt bore. Note that the 6.0mmx1.0mm threads for the hold down bolt begin 45mm below the top of hole down a smooth 8mm bore. I sent Jim these photos and we are deciding if he can tackle this locally. The challenge here-Jim has roughly 35mm of that broken 6mm bolt protruding into that smooth 8mm bore-and this broken bolt segment is below the surface of that bore's opening. Doktor A

mobileoilchange
03-12-2008, 04:08 AM
is removing the head out of the question?

if you remove the head you can put the head in a mill (bridgeport) and drill it out. or you could remove the head, drill a hole into the center of the bolt and try using an ezout. place the head into an oven or hot plate to evenly heat it, and try removing the broken bolt with an ez out. but if you break the ez out your screwed because its hardend.

to me...and this is just my opinion, i would remove all the injector bolts and replace them with studs. you can get long studs with a inverted hex, like a set screw and use them in place of the bolts. then when its time to remove the injector you just undo a nut. (if the stud turns while removing the nut, then you could also use a allen wrench to hold the stud and a box wrench on the nut) studs also dont put as much stress on the threads as a bolt does.

im an ex tool and die maker by trade, and i use to buy long set screws up to 10" in length...although they were standard thread and not metric. stainless steel would be the way to go. you just need to find some that are threaded only on the ends and not the whole lenght of the stud.

ARP may have something.

PS the mechanic should of tried removing the bolt while the engine was hot, because the aluminum has a faster expansion rate then the steel bolt. and he should of tried loosening and tightening it a little at a time to slowly remove it.

abittenbinder
03-12-2008, 06:52 AM
Here are photos of the same #1 cyl injector bore and hold down bolt bore with the cam cover removed. To remove the cam cover all the injectors must be removed. To remove all the injectors means the engine has to be lowered for access to rear injectors(they are long). To remove the cylinder head from engine is many more hours labor in addition. I will suggest that Jim attempt a repair with head in place. Doktor A

solera
03-12-2008, 01:06 PM
I had a thought last night.

Would it be possible to enlarge the opening around, what remains,, of the bolt?

Is there plenty of metal to do so, and no passageways that you would cut into ?

I'm thinking, to about,, 14mm. (or whatever is needed, to do the job)

If we can do that,,, then we could have a tube machined to the proper length, say about 35 mm or so long.

Have it threaded on the inside.

Using a bolt and a few nuts, (locked in the top of our part) run it down on the exposed stud until it seats at the bottom.

Remove bolt and nuts. Now,,, run shorter new bolt into this, to hold down new injector..

I was thinking about using a small hole saw like tool to remove the metal from the head.

Possible ? or bad idea? :hmmm:


Or,,, having not actually seen it.

Is there any exposed thread already?

Enough to do this without,, removing any aluminum ?

mobileoilchange
03-12-2008, 02:10 PM
Re: Well, looks like my ''good luck'' ended..

--------------------------------------------------------------------------------
I had a thought last night.

Would it be possible to enlarge the opening around, what remains,, of the bolt?

Is there plenty of metal to do so, and no passageways that you would cut into ?

I'm thinking, to about,, 14mm. (or whatever is needed, to do the job)

If we can do that,,, then we could have a tube machined to the proper length, say about 35 mm or so long.

Have it threaded on the inside.

Using a bolt and a few nuts, (locked in the top of our part) run it down on the exposed stud until it seats at the bottom.

Remove bolt and nuts. Now,,, run shorter new bolt into this, to hold down new injector..

I was thinking about using a small hole saw like tool to remove the metal from the head.

Possible ? or bad idea?


Or,,, having not actually seen it.

Is there any exposed thread already?

Enough to do this without,, removing any aluminum ?





im not really understanding what you mean, but. if the broken bolt is 35mm (about 1 3/8" down into the hole) what if the exposed hole was enlarged and had a threaded insert installed (not a heli coil). you could then use a bolt that would be about 1 3/8" or shorter to hold the injector hold down in place. if you need a insert made let me know and ill whip you one out and mail it to you. i would just need the dimensions.

PS: DO NOT USE A HOLE SAW! it would be best to use a hand reamer to enlarge the hole slowly in steps. that way the hole will be round and straight. example: 7mm reamer, 8mm reamer, 9mm reamer etc etc until you get to the finished tap size. then tap the hole to match the threaded insert O.D.

if the mechanic uses a air or electric drill he may gaul the drill bit into the aluminum and break it off (bad bad bad), drill it on an angle, or make the hole out of round. It would be best to use a hand reamer and go slowly in steps, and use a cutting fluid like tap magic or kerosen.

Suba
03-12-2008, 02:57 PM
I've read enough about broken injector bolts that it's becoming a concern of mine. I understand the mechanics of the failure, but not the underlying causes that may exacerbate the failure. Are the guys who have these failures doing something unusual ( atypical )

I would like to ask Solera what his driving habits are. What sustained RPM do you normally run ? Would you consider your driving habits as spirited ? Do you carry weight, and if so, how much. Do you have a boost kit. Do you use fuel additives, and is so, what kind. What kind of fuel do you normally use ? Is there anything you feel you may have done to contribute to this problem ?

talkinghorse43
03-12-2008, 06:11 PM
I've read enough about broken injector bolts that it's becoming a concern of mine. I understand the mechanics of the failure, but not the underlying causes that may exacerbate the failure. Are the guys who have these failures doing something unusual ( atypical )

I would like to ask Solera what his driving habits are. What sustained RPM do you normally run ? Would you consider your driving habits as spirited ? Do you carry weight, and if so, how much. Do you have a boost kit. Do you use fuel additives, and is so, what kind. What kind of fuel do you normally use ? Is there anything you feel you may have done to contribute to this problem ?

Maybe this had something to do with the failure?

http://www.sprinter-source.com/forum/showthread.php?t=2720&page=2

Suba
03-12-2008, 06:58 PM
Maybe this had something to do with the failure?

http://www.sprinter-source.com/forum/showthread.php?t=2720&page=2

But of course. I had already suspected. There is never a free lunch.

solera
03-12-2008, 07:28 PM
Maybe this had something to do with the failure?

http://www.sprinter-source.com/forum/showthread.php?t=2720&page=2


No, it did not.

Actually i found the problem when i pulled the cover to look for where to wire that, in..

At that time, i cleaned the entire area and then drove it for a few weeks, to pinpoint which injector, was actually leaking.

But I will admit, I do not drive it like I'm trying for, high mileage. :D:

Suba
03-12-2008, 07:39 PM
But I will admit, I do not drive it like I'm trying for, high mileage. :D:

So let me get this straight. You abuse your van, then come crying to the forum when something breaks.......

Am I understanding this correctly ?

solera
03-12-2008, 08:08 PM
So let me get this straight. You abuse your van, then come crying to the forum when something breaks.......

Am I understanding this correctly ?

Where did I use,,, the word ''abuse'' :hmmm:

Was not the vehicle made,,, to drive..

Where does it say you can only use half of the pedal,, in the owners manual? :rolleyes:

Do you have the page # ?

Lastly, Grown men,,,,, don't ''cry''.. :smilewink:

Suba
03-12-2008, 09:00 PM
Please forgive me for not following, and adhering to the proper social cyber space guidelines that on one hand dictate the delicate level of sensitivity and social decorum needed to convey our innermost thoughts, yet on the other convey in the most concise and direct way possible the true meaning of the words typed therein....



Lastly, Grown men,,,,, don't ''cry''.. :smilewink:

Are you sure about that ? :smilewink:

solera
03-12-2008, 09:14 PM
Are you sure about that ? :smilewink:

Quite........... Bahahahahahah!!! :lol:

Suba
03-12-2008, 09:36 PM
Quite........... Bahahahahahah!!! :lol:

Are you a real man ? :thinking:

BTW, can you tell me about the first time you felt the urge to abuse your Sprinter ? :D:

solera
03-12-2008, 09:47 PM
I see, no need,,, to, repeat myself... :thinking:

mobileoilchange
03-12-2008, 10:17 PM
the injector went south,
the bolt didnt break because of the bad injector, it broke because it welded it self to the aluminum.
the mechanic didnt slowly loosen and slowly tighten the bolt back n forth, slowly working it out. one could apply anti seeze to a bolt to prevent it from "self welding to the aluminum" but of course it would of had to be applied before hand.

another problem is that the length of the bolt to its diameter makes it a easy target to breakage. when the threads are seezed the remaining shank of the bolt acts as a srping when force is applied from twisting of the material and the smaller diameter pitch of the bolt is where its gonna break.

this is also a problem on some ford and chevy aluminum heads where the spark plugs get seezed. when the plug is removed it takes the threads out with it. thats why its so important to apply anti seeze to the threads when installing bolts or spark plugs into aluminum.

this may of not happened if the head was at operating temps. the aluminum has a faster expansion rate then steel. but if it was already that seezed who knows. think of how many heating cycles the engine goes through day in and day out.

How many miles are on the vehicle???
i know its like Russian Roulette, but id almost would want to remove all the other injector bolts now and apply anti seeze to them. If the heads needs to be removed i would make sure to apply anti seeze to them.

mobileoilchange
03-12-2008, 10:22 PM
Are you a real man ?

BTW, can you tell me about the first time you felt the urge to abuse your Sprinter ?

how is he "abusing" his sprinter?
why does someone else care how someone else drives or treat their vehicles?
if its not a company vehicle, and hes the one making the payments, who cares.
the injector bolt didnt break because the injector took a crap.

now if he said "i added dual turbos and cranked the boost up to 30 psi, ported and polished the head, bored and stroked the bottom end...more cam, ported the intake. etc, then yeah you know he was out beating on it.

solera
03-12-2008, 10:24 PM
101K

N' it broke exactly where it transitioned,,, from threaded to not.

21 mm below the bottom of the bolt head.

abittenbinder
03-17-2008, 05:25 AM
Well-you can thank Jim(Herr Solera) for helping this injector hold-down thread/bolt project move well up my "critical to-do" list.

I have finished the design and spec drawings and have contacted the engineering dept of a large thread insert repair supplier-No, NOT Helicoil-I believe Helicoils are contraindicated in this application. This company will be supplying me with custom made installation tools and a supply of custom spec'ed inserts.

I will be assembling and marketing a COMPLETE repair kit with several "loaner tools" for the 612 and 647 engine which will repair damaged/stripped threads in the head (engine and head-in place) as well as remove inaccessible, broken hold-down bolts.

Should be ready by the end of the month. Details to follow on a separate thread so we can get the word out to everyone. Doktor A

kkanuck
03-17-2008, 07:52 AM
Well-you can thank Jim(Herr Solera) for helping this injector hold-down thread/bolt project move well up my "critical to-do" list.

I have finished the design and spec drawings and have contacted the engineering dept of a large thread insert repair supplier-No, NOT Helicoil-I believe Helicoils are contraindicated in this application. This company will be supplying me with custom made installation tools and a supply of custom spec'ed inserts.

I will be assembling and marketing a COMPLETE repair kit with several "loaner tools" for the 612 and 647 engine which will repair damaged/stripped threads in the head (engine and head-in place) as well as remove inaccessible, broken hold-down bolts.

Should be ready by the end of the month. Details to follow on a separate thread so we can get the word out to everyone. Doktor A



The Good Doctor comes to the rescue...... :thumbup:

Suba
03-17-2008, 02:21 PM
Are you a real man ?

BTW, can you tell me about the first time you felt the urge to abuse your Sprinter ?

how is he "abusing" his sprinter?
why does someone else care how someone else drives or treat their vehicles?
if its not a company vehicle, and hes the one making the payments, who cares.
the injector bolt didnt break because the injector took a crap.

now if he said "i added dual turbos and cranked the boost up to 30 psi, ported and polished the head, bored and stroked the bottom end...more cam, ported the intake. etc, then yeah you know he was out beating on it.

NO, he didn't say that.....but he DID say this.
----------------------------------------------------------------------------------------------------------------

Well i ended up buying the powerbox cr ''plus''......

http://www.tdc-technologies.com/

Got it installed,,, set it up to, setting ''#9''.. (came on ''3'')

The truck, hauls,,,,,,,,,,,,,, azzzzzzz :D

Well worth, the $389.

Now,,,,,,,,,,,,,,, if, it just stays, ''together''

sikwan
03-17-2008, 02:38 PM
NO, he didn't say that.....but he DID say this.
----------------------------------------------------------------------------------------------------------------

Well i ended up buying the powerbox cr ''plus''......

http://www.tdc-technologies.com/

Got it installed,,, set it up to, setting ''#9''.. (came on ''3'')

The truck, hauls,,,,,,,,,,,,,, azzzzzzz :D

Well worth, the $389.

Now,,,,,,,,,,,,,,, if, it just stays, ''together''

It may have caused the injector leak, but I don't think it caused a bolt to break. I think there's another thread that talks about another bolt breaking, but I think it's a bolt for the glow plugs. :hmmm:

Let's hope there's an easy solution to this. I would hate to do an inspection and find that I either have to remove an injector or glow plug and the bolt breaks! :rant:

talkinghorse43
03-17-2008, 04:06 PM
It may have caused the injector leak, but I don't think it caused a bolt to break. I think there's another thread that talks about another bolt breaking, but I think it's a bolt for the glow plugs. :hmmm:

Let's hope there's an easy solution to this. I would hate to do an inspection and find that I either have to remove an injector or glow plug and the bolt breaks! :rant:

No glow plug bolt, the glow plug screws in like a sparkplug. In some cases, could be an injector leak means the hold-down bolt was weakened through long term metal creep/fatigue (some bolts have broken in service) and will be prone to breakage on removal because leak residue also acts as a glue.

contractor
03-17-2008, 05:57 PM
No glow plug bolt, the glow plug screws in like a sparkplug. In some cases, could be an injector leak means the hold-down bolt was weakened through long term metal creep/fatigue (some bolts have broken in service) and will be prone to breakage on removal because leak residue also acts as a glue.

Please explain then what a "hold down" bolt is? Is this a head bolt or other bolt for assembly? Why would it leak? Blown head gasket? I'm not following this but it sounds really ugly:rant:

sikwan
03-17-2008, 06:55 PM
No glow plug bolt, the glow plug screws in like a sparkplug.

You're right. I think I'm thinking about the glow plug that sheared off.

abittenbinder
03-17-2008, 09:03 PM
Well-you can thank Jim(Herr Solera) for helping this injector hold-down thread/bolt project move well up my "critical to-do" list.

I have finished the design and spec drawings and have contacted the engineering dept of a large thread insert repair supplier-No, NOT Helicoil-I believe Helicoils are contraindicated in this application. This company will be supplying me with custom made installation tools and a supply of custom spec'ed inserts.

I will be assembling and marketing a COMPLETE repair kit with several "loaner tools" for the 612 and 647 engine which will repair damaged/stripped threads in the head (engine and head-in place) as well as remove inaccessible, broken hold-down bolts.

Should be ready by the end of the month. Details to follow on a separate thread so we can get the word out to everyone. Doktor A

We are referring to the hold-down bolt and its threads for the retention of fuel injectors. It is not common nor widespread but there have been cases of stripped threads in the bolt hole and/or broken hold-down bolts- which secure the injectors into the cyl head. Watch for my upcoming thread for my "in the vehicle" fix kit. Doktor A

mobileoilchange
03-17-2008, 09:18 PM
im wondering if this will be a problem on the 3.0l in the future.

solera
03-17-2008, 10:38 PM
The truck, will be coming home, in the A.M.

On the hook...........:smirk:

Let the project,,,, begin........:thumbup:

solera
03-17-2008, 10:43 PM
It may have caused the injector leak, but I don't think it caused a bolt to break.

It caused,,,,,, neither.

As stated in an earlier post, in this thread.... :smilewink:

I found the leak, while looking where,,,

to hook up, the powerbox CR

talkinghorse43
03-18-2008, 01:59 AM
im wondering if this will be a problem on the 3.0l in the future.

May not be since the v6 puts out less specific (per cc) torque and power than the i5. Probably, MB decided to detune the v6 (compared to the EU version for the Sprinter) to suit our fuel just so this wouldn't happen.

abittenbinder
03-18-2008, 06:04 AM
The truck, will be coming home, in the A.M.

On the hook...........:smirk:

Let the project,,,, begin........:thumbup:

My "do it yourself" (level 5) kit should be ready to ship by the end of the month. I have 3 different machinists working on custom spec tools as well as the thread insert supplier and 2 European tool companies supplying the German made MBenz tools.

I will do a mock-up of your failure (a worst case failure) here in the shop and fully test the kit before it's released. In addition to the parts you will keep- the thread insert, new hold-down bolt, new injector and its new seal ring- the majority of the kit will consist of loaner tools and fixtures with commensurate $$ deposits and rental fees.

The kit is designed to handle the full range of hold-down failure modes from simple stripped treads in cyl head, to the dreaded "worst case" scenario(yours)- a broken, inaccessible portion of the hold-down bolt recessed in the head's smooth hold-down bore but protruding from and seized in the base treads- as well as the "black curtain of death"- a fully coked and entrapped injector.

Injector removal will be accomplished with a easy to use tool set that can extract the most extremely coked/ seized injector. Doktor A

cerickson
03-19-2008, 01:41 AM
Hello everone,
I just went through this say thing. I have a 2006 sprinter with 192,000 milkes on IT. The bolt broke off in the #2 Injector hole, Dealer quoted me like 4400.00 for the new head. We redrilled out all the injector holes with head still on vechile, and I was also able to match up the injector hold down bolts locally, I just got my truck back total cost to me is $300.00 so far. I will keep ypu all posted. Thanks Andy for all the help.

guisar
03-19-2008, 02:38 AM
Why is it exactly that customers are being charged because a mechanic broke off a bolt? I've read through this thread and am very concerned because as Dr. A has advised avoiding this problem does not seem to be a DIY job, it's VERY expensive for the dealer to do the preventative maintenance and the dealers seem to be fobbing the fix off onto the customer after it seems they broke the injector. I'm sure I'm misunderstanding what's going on here; at least I hope so....

abittenbinder
03-19-2008, 03:22 AM
Why is it exactly that customers are being charged because a mechanic broke off a bolt? I've read through this thread and am very concerned because as Dr. A has advised avoiding this problem does not seem to be a DIY job, it's VERY expensive for the dealer to do the preventative maintenance and the dealers seem to be fobbing the fix off onto the customer after it seems they broke the injector. I'm sure I'm misunderstanding what's going on here; at least I hope so....

I talked with Jim after he had quizzed the dealer. I have little doubt the bolt was doomed regardless of the dealers efforts to remove it intact. It was likely seized in the cyl head threads and likely weakened as well.

What worries me about ANY repair procedures involving the injectors or their hold downs- I do not think the dealers or most repair shops quite understand the operation and appreciate the details-in particular, the tooling and techniques needed to assure proper seating of a new injector seat seal ring and the hold down bolt. I have heard from several owners that experienced failure or leakage shortly after injector "repairs". Doktor A

abittenbinder
03-26-2008, 07:40 PM
Latest update: The injector hold-down repair kit project is progressing well. In addition to the 3 machinists, the thread insert company, and 2 German tool companies -I now have a metallurgist and an engineer with a high performance/aerospace fastener manufacturer involved. The "DIY" repair kit will not only repair broken bolts and/or stripped threads but we will also include custom fail-safe "super" bolts to replace the OEM stretch bolts, as well. All without removing the cyl. head (or engine) from the Sprinter.

Coincidentally, I had a frantic phone call from a "fleet" owner today. Someone I have never spoken with before. He was just told by his Dodge dealer that he needs a replacement engine for his '06 w/120k. He will likely be the first trial run, under actual shop (not lab) conditions, for the repair kit. Doktor A

solera
03-26-2008, 09:06 PM
He will likely be the first trial run, under actual shop (not lab) conditions, for the repair kit. Doktor A

Sooooo :hmmm:

That, makes me,,,, #2 ? :laughing:

abittenbinder
03-26-2008, 09:27 PM
Sooooo :hmmm:

That, makes me,,,, #2 ? :laughing:

Trust me Jim, in a "first trial run", #2 is the best place to be. Doktor A

solera
03-26-2008, 09:33 PM
Ok.... :hmmm:

Yer, the,,,,,,,,,,,,,, Doktor.. :smirk:

abittenbinder
03-28-2008, 07:12 PM
Hello everone,
I just went through this say thing. I have a 2006 sprinter with 192,000 milkes on IT. The bolt broke off in the #2 Injector hole, Dealer quoted me like 4400.00 for the new head. We redrilled out all the injector holes with head still on vechile, and I was also able to match up the injector hold down bolts locally, I just got my truck back total cost to me is $300.00 so far. I will keep ypu all posted. Thanks Andy for all the help.

The above quote (early in this thread) is from a second Sprinter owner (Christopher). Chris initially called me AFTER he had his tech do a DIY injector hold down repair using a helicoil and SAE sized grade 8 bolts. His local independent tech repaired the one hole (w/ stripped threads) using a helicoil and preemptively oversize drilled the other 4 hold down threaded holes and tapped them for slightly larger SAE grade 8 socket head bolts.

Chris called today to let me know his DIY fix, grade 8 replacement bolt, had broken after apparently audibly leaking for the past few weeks.

My analysis: The OEM hold down bolt is a metric 8.8 grade bolt-roughly the material equivalent of a grade 5 bolt. His grade 8 bolt is a minor upgrade. The fasteners clamping force, cyl head's injector seat condition, the bolt's metallurgical and dimensional specs, bolt production quality (Chinese?), the bolt's lateral positioning in the hold down pawl are all critical factors to a successful and lasting repair.

Beware of quick fixes-it may render the cyl head unfit for a second, proper, permanent repair. Doktor A

abittenbinder
04-02-2008, 05:40 AM
Latest update: The final custom made tool is nearing completion. Hope to have the first trial run of the kit sometime next week. Doktor A

KenB
04-02-2008, 06:13 PM
On a personal note, affirming Herr Doktor... a quick fix can be preemptive to an actual fix ever happening.

WARNING, all dimensions listed are on an "as remembered from childhood" basis... at least I would call anyone of the age that I was then, a child now...:smilewink:

About 30 years ago, before I was old enough to understand the above, a neighbor (older than my dad) asked over the fence if we had a tap about 1/2" to repair the bad threads on his waterwell pump... being approximately too young to say "NO", I said "let me check" and went to the tool box, which had one about that size, and took it to him. :thinking:

The mysteriously marked tap said something like "13" on it and neither one of us (me about too young to know what the metric system was, and him too much a citizen of 1940's USA...) knew what "13" meant. So the eldest of us (him) went off and tried it... and then brought it back declaring that it went quite well and tapped/cleaned up the threads quite nicely.:thumbup:

Now, what he did not tell me was that he had not tried any new plug/pipe in the newly cleaned up threaded hole... what he told my dad later (when he got over his embarrassment) was that he had tapped out the drain plug hole on his waterwell pump to accept a 13mm Metric Sparkplug!!! :thumbdown:So, his "permanent" fix was to put a new sparkplug in the hole and hope that it did not rust out for a while. He may have found a 13mm short bolt to fill the hole later, I do not know.:smirk:

KenB

mobileoilchange
04-02-2008, 10:49 PM
i have 1/2" - 13 taps (1/2" diameter - 13 threads per inch) but never in my days have i seen or heard of a 13 mm spark plug thread. i know of 14mm but not 13mm
lol

solera
04-03-2008, 09:26 PM
Latest update: The final custom made tool is nearing completion. Hope to have the first trial run of the kit sometime next week. Doktor A

Well that's certainly,,,,,,,,, good news.. :thumbup:

I'm getting tired,,, of driving this d**m ford econoline rental.. :rolleyes:

Drivers seat, gives absolutely no,,, support.. :idunno:

abittenbinder
04-23-2008, 10:11 PM
Latest update- The all important German milling tool which performs 4 cutting/reaming/refacing operations at one time, was a well established tool-or so I thought. It is now being reconfigured after I raised a concern regarding its design and operation. The German manufacturer is air expressing me a modified version and I should receive it on Thursday. I will be testing the the new milling tool and the completed "kit" on a workbench head at the end of the week.

The special tools made here- in house, have turned out beautifully. These consist of a special fixture (designed to work in the 612 as well as the 647 heads) with several drill guide inserts, as well as drill stops. Doktor A

solera
04-23-2008, 11:00 PM
Cool............... :cheers:

abittenbinder
04-24-2008, 03:39 PM
Originally Posted by cerickson
"Hello everone,
I just went through this say thing. I have a 2006 sprinter with 192,000 milkes on IT. The bolt broke off in the #2 Injector hole, Dealer quoted me like 4400.00 for the new head. We redrilled out all the injector holes with head still on vechile, and I was also able to match up the injector hold down bolts locally, I just got my truck back total cost to me is $300.00 so far. I will keep ypu all posted. Thanks Andy for all the help. Chris"

The above quote (earlier in this thread) is from a second Sprinter owner (Christopher). Chris initially called me AFTER he had his tech do a DIY injector hold down repair using a helicoil and SAE sized grade 8 bolts. His local independent tech repaired the one hole (w/ stripped threads) using a helicoil and preemptively oversize drilled the other 4 hold down threaded holes and tapped them for slightly larger SAE grade 8 socket head bolts.

Chris called today to let me know his DIY fix, grade 8 replacement bolt, had broken after apparently audibly leaking for the past few weeks.

My analysis: The OEM hold down bolt is a metric 8.8 grade bolt-roughly the material equivalent of a grade 5 bolt. His grade 8 bolt is a minor upgrade. The fasteners clamping force, cyl head's injector seat condition, the bolt's metallurgical and dimensional specs, bolt production quality (Chinese?), the bolt's lateral positioning in the hold down pawl are all critical factors to a successful and lasting repair.

Beware of quick fixes-it may render the cyl head unfit for a second, proper, permanent repair. Doktor A

Update: Christopher(the other Sprinter owner) is still struggling with his injector hold downs. It is unclear whether Chris's tech properly dimensioned and torqued the makeshift hold down hardware. More importantly it has not been established if the tech was able to properly reface the injector seal surface at the bottom of the injector bore. These are CRITICAL factors. Stay tuned.

Also-a repair facility in California has just shipped me a 612 cylinder head which had a leaking hold down repair on cyl #1 and that #1 injector ABSOLUTELY seized in its bore. They were unable to extract the injector.

Upon inspection I can see the original hold down bolt has broken flush with its hold down cyl head threads at the bottom of its bore. A make-shift repair had been done (by an earlier shop) by threading the bore above that and tapping it for an oversize bolt. They then apparently installed the injector with some kind of Locktite bearing retaing compound smeared in the bore!! No wonder the second shop could not remove the injector.

I have successfully extracted the "glued in place" injector and can clearly see that no attempt had been made to properly prepare the injector seal ring surface in the bore for that first repair attempt. This head will be repaired correctly and should perform dependably. Doktor A

abittenbinder
04-26-2008, 05:54 AM
Latest update- The all important German milling tool which performs 4 cutting/reaming/refacing operations at one time, was a well established tool-or so I thought. It is now being reconfigured after I raised a concern regarding its design and operation. The German manufacturer is air expressing me a modified version and I should receive it on Thursday. I will be testing the the new milling tool and the completed "kit" on a workbench head at the end of the week.

The special tools made here- in house, have turned out beautifully. These consist of a special fixture (designed to work in the 612 as well as the 647 heads) with several drill guide inserts, as well as drill stops. Doktor A

The redesigned, reconfigured German tool arrived as promised. I really have to commend these people. The milling tool redo addressed all 3 concerns I had with its design and dimensioning.

I tested it on a, off the engine, 612 cyl head with serious injector seat contamination and some erosion damage of this cyl 1 injector seat. Outcome -perfect. I tested my complete repair set and installed all 5 carbon steel, custom, hold down thread inserts. Cylinder head is now BETTER than new.

Next test will be to simulate various broken bolt scenarios- to fully "worst case test" the custom fixture, drill bits and drill guides. Doktor A

solera
04-26-2008, 12:43 PM
Well, that's,,,,,,,,,,,,, certainly good news... :thumbup:

abittenbinder
04-28-2008, 03:45 AM
Performed the "worst case-broken hold down bolt" test this weekend. I modified a new OEM hold down bolt to break at thread/shank transition when torqued. Mounted an injector into a good used head (utilizing original hold down cyl head threads) using this bolt and red Locktite to simulate a seized broken bolt. See photo for break location.

This "worst case" break left the broken segment just below the surface in the hold down bore with approx. 30 mm projecting upward from its threaded bore but below the surface of the larger bore it is located in.

Next photo shows the remains of the broken segment after the repair operation. The newly threaded bore is now ready for its custom length carbon steel thread insert. Test was successful and revealed the challenges of continuously removing metal shavings from deep inside a narrow, bore-within-a-bore, while using special long length, lubricated drill bits and the custom made drill guides and custom made fixture. Doktor A

solera
04-28-2008, 01:35 PM
:thumbup:

sikwan
04-28-2008, 04:02 PM
Next photo shows the remains of the broken segment after the repair operation. The newly threaded bore is now ready for its custom length carbon steel thread insert. Test was successful and revealed the challenges of continuously removing metal shavings from deep inside a narrow, bore-within-a-bore, while using special long length, lubricated drill bits and the custom made drill guides and custom made fixture.

How long was this process?

I'm thinking it would vary depending on the position (wiggle room) of the offending bolt. :hmmm:

abittenbinder
04-28-2008, 08:57 PM
How long was this process?

I'm thinking it would vary depending on the position (wiggle room) of the offending bolt. :hmmm:

The failure modes can vary from something as simple (but catastrophic) as stripped threads in the cyl head hold down bolt bore to the dreaded- seized and broken hold down bolt. A broken hold down bolt can vary in the length of bolt remaining in its threaded bore (and protruding into the larger bore diameter above).

The "worst case" scenario which was simulated here- involved the max. possible remaining bolt length, inaccessible and needing to be machined away. Almost 2 inches in length, below the surface in the larger, recessed bore. Only the lower portion of the "worst case" broken bolt length is in its threaded bore.

Removing this much of a bolt length is tedious because the fixture and guides must be removed periodically for removal of machining swarth from the extremely small working volume. The bit flutes cannot expel material quickly enough because of the depth of the bore and the closely toleranced drill guides used in the fixture.

The entire repair procedure is not lengthy but requires skill and experience. Replacing the Sprinter cylinder head, on the other hand, is a very time consuming as well as bank account consuming nightmare. Doktor A

solera
04-28-2008, 10:11 PM
Local ''field test'', next?

Aqua Puttana
04-28-2008, 10:29 PM
Doktor A,
You may have covered this elsewhere, but if (when?) I should ever need to remove the injector hold down bolt by your experience is it best to do it with a hot engine as you suggest with the glow plugs? Thanks, vic

abittenbinder
04-29-2008, 01:04 AM
Doktor A,
You may have covered this elsewhere, but if (when?) I should ever need to remove the injector hold down bolt by your experience is it best to do it with a hot engine as you suggest with the glow plugs? Thanks, vic

The glow plugs are a unique case. They have a large surface area of thread exposure, they are hollow, and they are not easily removed if they snap off. The existing tool sets, generically designed to extract broken ones from MBenz CDI engines, are not easily employed (if at all) in the specific Sprinter CDI engine configuration.

The injector hold down bolts are prone to several failure modes. They can break or stretch from cyclical stress. They can break when removal is attempted- if they are weakened and their threads are seized. They can strip the mating retaining threads in the aluminum head, again from cyclical stress.

A hot engine may help with hold down bolt removal IF a healthy bolt with healthy cyl head threads is being removed due to an injector failure. BUT, if the injector is being removed due to leakage at its cyl head seal ring, the bolt or its mating threads may already have been compromised. And unlike the glow plugs, we now we have a solution for the broken hold down or stripped thread fiasco. Doktor A