CDI injector bolt repair Time Sert

Discussion in 'Engine' started by E270 Owner, Mar 24, 2014.

  1. E270 Owner

    E270 Owner Hardcore MB Enthusiast

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    Hi

    Please note that the following information is one of a preferred methods of repair that I think the home mechanic should be able to apply him/her self to do.
    It is by no means a step by step info/pictorial guide but a competent enthusiast should be able to complete a repair to a high standard.
    I have no doubt there will/maybe comments on some parts of the process I omitted or got wrong forgot or simply didn't include for whatever reason so please bear this in mind that its a fast guide I put together due to the amount of posts I see here regarding this issue.

    Also this is a my way guide not a "you must" one.

    Thanks for reading.

    Disclaimer

    I bear no responsibility for persons injuring themselves or other persons or property due to the content of this guide.

    How to repair a failed injector clamp bolt field remedy.


    This covers replacing the OEM
    M6x1.0x79mm
    bolt with a
    M8x1.25x50mm
    Stainless steel Allen key bolt.

    Parts used are Wurth Time Sert Kit
    Art: 0661 8 125
    Time Sert installation > http://www.gmdesolutions.com/equipment/docs/Wurth_USA_Partnership.pdf
    Mercedes Injector cleaning kit
    W 611 589 006 800
    Mercedes Injector grease
    A 00 198 942 511
    Stainless Steel Allen Bolt 8x1.25x50mm

    Repair condition description.

    These bolts fail stripping the threads in the cylinder head due to.
    1. Incorrect clean/repair following injector seal replacement
    2. Multiple stretch bolt use.
    3. Over/under torque setting.
    4. Metal fatigue.
    5. Other*

    There are various methods to make this repair not withstanding using the Mercedes extended repair Time Sert kit that allows a deeper insert to be applied,
    I have used these and found no benefit from this method using a top insert and shorter bolt rather than a lower one and a longer bolt.

    The common rail to injector diesel feed pipe may need replacing if it's beyond repair limits due to stress from the injector forcing its way out of the injector housing.

    Helli-coils
    I don't recommend their use in this repair although as a one off repair they are perfectly viable, as injectors need to be serviced and the bolts removed T-Serts suit the purpose better for multiple usage.

    Tools & Stuff
    ^Part numbers and bolt/s mentioned above^
    Electric Drill
    Tap T-bar handle + extension
    30w oil
    Vacuum cleaner
    Clean rag

    Prepare/Repair.
    1. Remove the diesel rail pipe, bolt, clamp, and injector, replace/repair the injector rail pipe.

    2. Insert a brass plug into the injector nozzle hole using the long threaded extension in the Mercedes injector cleaning kit.

    3. Clean the injector seat with the handled extension brush in the Mercedes injector cleaning kit using firm pressure but not too hard.

    4. Clean any carbon residue from injector housing using Carb cleaner, thoroughly clean the seat and housing.

    5. If the injector seat shows signs of damage from extended blow by, use an injector cutting tool to re-seat the seal.

    6. Plug the injector housing hole with a clean cloth to prevent swarf ingress from drilling.

    7. Drill the old injector bolt threads out with the Wurth drill bit, vacuum the area to remove swarf.

    8. Ream the top of the hole with the Wurth reamer until it hits the stop collar on the bit, clean up the swarf.

    9. Apply some oil to the Wurth tap bit, carefully offer the tap into the hole and start turning with a little downwards pressure keeping the tap inline with the hole slowly turn until you feel it bite and start to tap straight, tap until half way, back the tap out, clean off the swarf from the hole area and the tap bit, apply oil to the tap again, insert the tap turning with your fingers only until the half way point then resume with the tap handle until the tap is fully in, remove the tap and clean out the hole using the vacuum then clean up with wd40 in the hole pick out as much swarf as you can.

    10. Apply oil to the Wurth Driver Tool, screw a T-Sert on to the end threads as far as you can by hand, apply oil to the outside of the T-Sert offer up to the newly tapped hole and slowly turn it in by hand till it tightens up then begin to turn with the T bar handle you used on the tap until you feel resistance, keep going it will loosen off as you pass through the bottom of the insert, wind out the Wurth Driver Tool and clean up the area of any oil and swarf.

    11. Remove the injector housing cloth, clean up swarf and oil debris, remove the injector nozzle brass plug ensure the insert threads are clean.

    12. Install the injector applying the injector grease to the injector body not the nozzle area, replace the injector copper seal with a new one.
    The Stainless Steel M8x1.25x50mm Allen Bolt torqued to 14Nm then to 18Nm.

    Below are some images to help visualize the above guide.

    Hope it helps some of you out there struggling with this problem.

    Mercedes Injector Cleaning Kit.

    [​IMG][​IMG]



    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
    Last edited: Mar 24, 2014
    8 people like this.
  2. shorty

    shorty Hardcore MB Enthusiast

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    Nice write up ,

    Hopefully Ill never need to do this , LOL

    Thanks
     
  3. Jane270ML

    Jane270ML Hardcore MB Enthusiast

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    This should help quite a few of us, thanks.
     
  4. OP
    OP
    E270 Owner

    E270 Owner Hardcore MB Enthusiast

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    Thanks

    I did forget to mention drilling the injector clamp hole to accommodate the new bolt but it will be obvious at the time :)
     
  5. metaron

    metaron New Member

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    Amazing post, bloody helpful and well thought out!

    I just had one problem - Mercedes wouldn't sell me the Mercedes Injector cleaning kit(!): W 611 589 006 800 which I really wanted to stop debris going down the hole.

    Would it be possible to just make/machine the bungs? - If you have the dimensions handy I'll send you a big sloppy wet kiss:bannana:eek:r is there anything else that is safe for filling the holes in?
     
  6. bob6600

    bob6600 Hardcore MB Enthusiast

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    My dealer had no problem selling me the kit, although for a one off I didn't want to pay the near £100
     
  7. metaron

    metaron New Member

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    Cheers for letting us know the price Bob.

    Well if that's how much they cost I'm definitely improvising something as bungs.

    There's 2 bits of information which would really be useful for somebody reading this post and they are:

    1: If needed - What size is the injector seat cutter and is it flat or angled? (Have read it's 17 X 17mm angled but could not confirm)?

    2: Where do you apply ceramic grease? I know it is all the way down the shaft and the injector body but do you also have to grease the seat and both sides of the copper washer too?
     
  8. OP
    OP
    E270 Owner

    E270 Owner Hardcore MB Enthusiast

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    Hi

    There's no mention of an injector seat cutter, Mercedes recommend you don't re-cut the seats but polish them using the kit as shown in the pictures I took.

    The grease is applied to the injector body stopping before the nozzle area and not on the copper washer,
    if you do the bolt modification as shown above no grease is needed, if you use a new Mercedes stretch bolt then clean the threads up in the holes
    with a long tap and apply grease sparingly to the new bolts.

    Also

    The bungs are screwed on to the end of the rod and then placed in the nozzle hole then the rod removed leaving the bung in place.

    This kit is available on e-bay minus the bungs.

    Genuine Mercedes Benz Injector Bore Cleaning Brush Tool Kit | eBay

    Call them they may have other kits.

    If you get stuck I can send you a brass bung you only need one :)
     
    Last edited: Mar 23, 2015
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  9. metaron

    metaron New Member

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    Deal! PM me your email (as I can't PM as don't currently have permissions) and I can paypal you a fiver if you like and my address. Just let me know if this is enough.
     
  10. metaron

    metaron New Member

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    And what about greasing the injector recesses?
     
  11. bob6600

    bob6600 Hardcore MB Enthusiast

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    Mercedes Special Grease :)

    If just the one, E270 Owner may be able to sort out a smidgen for you
     
  12. metaron

    metaron New Member

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    :wallbash: Too late.. I already paid 16+vat from mercedes today for the grease! And yes it is just the one injector.

    With regards to the recesses I didn't know if you greased the seat at the very bottom where the copper washer sits.
     
    Last edited: Mar 23, 2015
  13. bob6600

    bob6600 Hardcore MB Enthusiast

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    No, just the 'body' of the injector.

    For those who think it's not important or the grease is too expensive, it took me hours to get 2 of my injectors out (4 weren't too bad) and I greased them all using the above on refitting. A short while ago I found one seemed to not have been seated correctly (the one which took the longest to come out!) so I removed the bolt and clamp and removed the injector with one hand in minutes. Well worth the expense.
     
  14. OP
    OP
    E270 Owner

    E270 Owner Hardcore MB Enthusiast

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    PM sent

    Ok apologies for the re-cutting comment as I did mention it in the original post and it is done only if damage has occurred to the seat.

    Dont put grease near the washer or nozzle as already mentioned.
     
  15. metaron

    metaron New Member

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    Got your PM thanks and have sent you my address. I will order that cleaning kit off ebay now and hopefully within a few days I should be good to go.

    What's the opinion on simply re-tapping to use a bigger bolt without using a time-sert?
     
  16. OP
    OP
    E270 Owner

    E270 Owner Hardcore MB Enthusiast

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    Applying torque to aluminium threaded holes isn't the best idea with regard to these retaining bolts, and probably why Mercedes have such a failure rate compared to other designs on injector retaining methods.
    The OEM bolt is ridiculously long and thin and probably needs to be to retain the required tension on the injector retaining clamp, using a T-Sert allows multiple torque applications and using a re-usable stainless steel bolt keeps costs down and securely keeps the injector in place once and for all.

    OEM Stretch bolt M6 1.0 x 79mm

    [​IMG]

    M8 1.25 x 50mm stainless steel Allen bolt

    [​IMG]










    .
     
    Last edited: Mar 24, 2015
  17. bob6600

    bob6600 Hardcore MB Enthusiast

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    One of mine has been bodged in the past, it is actually an M10! I replaced the bolt with a hex type stainless steel above and it has been fine since (3 years).

    I would use the correct repair where possible but if it is done right, they will hold
     
  18. metaron

    metaron New Member

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    Have been educating myself today about the time-serts and can't believe just how much better they are than helicoil type inserts which is cool because I've not invested a penny into any thread repair kits but will defo pay the extra and get the Wurth gear now.

    I have two more quick questions for you:

    Regarding the M8x1.25 time-serts - do these come in different lengths and if so which one should we use?

    What depth do you drill the hole to seeing as the new M8 stainless bolt is 50mm?
     
    Last edited: Mar 24, 2015
  19. OP
    OP
    E270 Owner

    E270 Owner Hardcore MB Enthusiast

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    The image in the first post showing the application of the T-Sert is all you need, and the part number for the kit.

    Using this method stops you from drilling too deep, as the cylinder head coolant routes are at the bottom of the bolt holes, go too far and your into the coolant water way.

    The Kit has correct drill lengths you cant damage the water ways, the 50mm bolt passes through the T-Sert and wont bottom out.

    The kit comes with the correct T-Sert lengths, you can order longer ones cant remember the choices now as I home.

    Extra Tea and biscuits were ordered today thank you for that. :thumb:

    :)
     
    Last edited: Mar 25, 2015
  20. WG M-B

    WG M-B Auhorised Forum Sponsor Authorised Forum Sponsor

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    There are around four different lengths
     
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