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 >
GM Approved Special Tools and Equipment
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.
