I just go done doing a diesel purge, and filter change. Car runs much smoother. I noticed that one of the injectors is leaking at the middle junction (below the return line ports, but above where it meets the head). I tried to tighten it, but it didn't seem to move at all. Is there a way to tighten it on the car?

Are you sure it's not the return line leaking?

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On some nights I still believe that a car with the fuel gauge on empty can run about fifty more miles if you have the right music very loud on the radio. - HST

1983 300SD - 305000
1984 Toyota Landcruiser - 190000
1994 GMC Jimmy - 203000

https://media.giphy.com/media/X3nnss8PAj5aU/giphy.gif

Spray it clean with brake cleaner, then run it and watch for where it leaks from. As stated above, usually it is the cloth braided return line that leaks.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Morning Guys,

Over the weekend I rebuilt my injectors -- installing the Mohawk needle assemblies. Cleaned the injectors by soaking in carb cleaner. Reassembled using a light coat of motor oil on the threads, torqued to 75 N-m. They all balanced out at 2100 psig (144.8 bar) +/- 100 psi. I now a small leak on #1 at this coupling. I will remove and retorque but while I am at it, does anyone have experience or advise using teflon thread tape (T-tape) on these threads?

Thanks, Larry

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Larry in Mobile, AL
'83 300SD "Goldfinger" 145K Mi W126 E-617.95 T-722.3 15" Bundts

Everyones idea of rebuilding seems to be different.

When Injectors are rebuilt the precision surfaces inside of the injector (the flat part of the Upper Body and bot sides of that Plate that goes in the middle) are lapped on a Lapping Plate. This makes them flat again so that they can seal.

The other possible is that something got trapped inbetween the precision surfaces when the injector was assembled like dirt, lint a hair and so on. It does not take much to create a leak.

If it was me removing the Injector and I had no way to lap them; I would take it apart and dip all the part and inspect the surfaces for anything that might have gotton trapped.

When you asseuble Injectors it is a good idea to have a bowl of clean Diesel Fuel when you assemble the Injectors. Just before you assemble them you dip them in the Fuel. Besides lubricating the parts it helps to float of any dirt or lint that is sticking to the surface. Dip and assemble.

If you are curious pick an area of your Garage you believe is clean. Dip a nice clean piece small piece of Sheet Metal in Diesel Fuel. Lay it on the bench and come backe in 15 minutes and obseve all the stuff that is sticking to it.
There is alot of crap floating in the air and even the lint for a Rag or a Paper towel can sometimes cause problems with fuel injection parts.

When I did this sort of work I would dip the parts in the Diesel Fuel and blow them off with filtered compressed air and assemble them right away.

How to rebuild injectors
http://vincewaldon.com/index.php?option=com_content&task=view&id=20&Itemid=28

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84 300D, 82 Volvo 244Gl Diesel

Thanks much for the quick response.
I need to correct an error -- the injector assemblies are Monark, not Mohawk.
Lapping the surfaces is the 1st I have heard of in the rebuild process, and your link to the Vince Walden page is much appreciated. Now that I have had the injectors apart the lapping makes sense. I do think the parts were clean upon reassembly. After soaking in the carb cleaner I blew them dry with filtered, dry air, and reassembled immediately. And, I toyed with the idea of using anti-seize on the threads, so I am going to take Vince's cue on this.
Larry

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Larry in Mobile, AL
'83 300SD "Goldfinger" 145K Mi W126 E-617.95 T-722.3 15" Bundts

I would only fix the one that is leaking leave the rest alone.

I do not remember what Vince said but, put the anti-seize on the outside threads that thread into the cylinder head. The exception might be if this Engine was on a Boat.

I do not agree with everthing that is in the Injector rebuilding thread. I think you should a the very least use a plate of glass and some lapping compound used with water or oil instead of the emery paper on glass. Rock Shops sell the lappig compound to folks who polish rocks.

I use 500 grit while anothe Member said he uses 1200 grit compound. a 1/2 teaspoon would be enough to do a 2-3 whole sets.

I am not naming any seller in particular but if you have some spray Nozzles to sell; how can you sell them to Folks?
One of the answers is to tell the buyer that all they have to do is just swap the Nozzles and everthing will be OK.
Do not mention Pop-testing or that in a Fuel Injection Shop that they would lap the Injector parts.
Indeed just swapping the Spray Nozzles and doing nothing else could be an improvement if you Spray Nozzles were shot. Even if the Pop-pressure was off and they were not balanced at leat the Fuel would be Atomizing better.
But, as you see without doing the whole job there is a chance of leaks and if you read some of the threads some Folks have success with the Nozzle Swap and others end up with a leak or 2.

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84 300D, 82 Volvo 244Gl Diesel

As it turns out, I had a 3000 grit tape for sharpening knives, so I polished the surfaces on #1, included your step to keep everything in diesel til reassembly, rechecked the pop, and added a 0.05 mm shim to get it to 2150 psig. No leaks and there is a noticeable difference in the way she runs. Love this forum! Thanks!
Larry

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Larry in Mobile, AL
'83 300SD "Goldfinger" 145K Mi W126 E-617.95 T-722.3 15" Bundts