? How to fix leaky injectors ?

[royzell]

Hi all,

Last week I was working on my '84 6.9. It wasn't starting so I tested the glow plugs (7 / 8 were dead) so I replaced those and it fired right up.
However, to get at 2 of them I undid the clamps on the steel fuel lines to get a socket and extension on the glow plugs.
When I put everything back together, 2 injectors leaked like a sieve. I have tried replacing o-rings, the plastic 'hat' that covers them, the rubber fuel return lines and clamps to those injectors.
It is hard to tell exactly where the leaks originate because a lot of fuel comes out at once.
I'm wondering if unseating the old connection between the fuel line and injector is the problem.

Is there any product like teflon tape (for plumbing) that can be applied to the threads to seal that connection ?

Any other ideas ?

Thanks

 

[Diesel JD]

The big concern I have is did you put the clamps back on the hard lines when you finished. If not its very possible that those lines may be cracked and need replacement. Additionally if the hard lines have been taken loose at the injector then there is a risk of crossthreading it. The injector typically has very soft metal threads and they can be easily damaged. Of course when one part of the return system is disturbed it is often the case that you fix one leak and another pops up until you go ahead and replace all the orings. Hope you get it fixed,
JD

 

[smoking89IDI]

And welcome to the site!

 

[LUCKY_LARUE60]

Additionally if the hard lines have been taken loose at the injector then there is a risk of crossthreading it. The injector typically has very soft metal threads and they can be easily damaged.
JD

That is my very thought also. What I do when putting the injector lines on is push them down and hold them with one hand and screw the nut down with the outher hand, if I can not at least get the nut to go half way down or more I feel it is starting to cross thread and I retry. The nuts turn very easy and you can almost screw the nuts all the way down by hand.

Jim

 

[royzell]

Hi Guys,

Thanks for the thoughts, but no, nothing is crossthreaded or cracked. (I learned the hard way a few years ago on my other truck). I was able to turn the fuel line nuts by hand until final tightening.

 

[Diesel JD]

Well if nothing is crossthreaded or cracked then it HAS to be one of the return lines or caps, unless the injector body itself has cracked. I don't know if that is likely, cdon't recall hearing of it in my years browsing IDI forums too often or ever in my experience with my own truck.

 

[fx4wannabe]

The hard line could have a pin hole in it. I had that happen to one of mine once. It could also be a bad return cap. Hard to say without seeing it. Sometimes these things can drive ya nuts till you finally find where its come from.

 

[suv7734]

Hi all,

Is there any product like teflon tape (for plumbing) that can be applied to the threads to seal that connection ?

Any other ideas ?

Thanks

Did the lines get bent at all in trying to gain access?
You might want to check and see if a bit of dirt got between the injector and the seat on the line.
The lines seal to the injectors and the threads are a 'clamping device' rather than a seal. Teflon tape is a big ugly around fuel systems, any stray strand and it will clog up an injector or the pump very quickly.

 

[Andylad13]

see if the cap has a crack in it.