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Question From Experience...Proper Tools For Injector Feed Lines?

7K views 14 replies 8 participants last post by  StealthDiesel 
#1 ·
Hey all so I have a quick question...I've yet to have any issues with injector line #4 (I check it often) but I figure it's about time to go ahead and just replace it with the updated version that has the new style clamp/isolator.

Obviously some specialty tools will help with the job so I was going to go ahead and purchase a few things.

My question...there's 2 types of crows feet wrenches (3/8 drive)...the standard ones then there's the 5 point style/flare wrench ones.

Sizes for the line nuts are 19mm, and 24mm for the injector tube nut. I'd like to counterhold the tube nut while I break the line nut free on the block side, I'm wondering if a standard 24mm combo wrench can get in there and allow the 19mm standard wrench in there? I plan on breaking everything free with standard wrenches (or stubbys, I have those too) but for torqueing down the feed line nuts, I'm wondering which version of crows foot would work best:

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Thanks in advance!
 
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#2 ·
I went ahead and just ordered a standard set of crows foot wrenches from Craftsman. Figured they will be able to get the job done as well as serve me well for other applications. The flare would be handy to have, but I don't think I'd get as much use out of them. Hopefully the change should go all smooth, seems pretty trivial to swap the lines out.
 
#3 ·
My personal opinion, I use regular wrenches for everything on those. The injector line nuts are 3/4", injector tube I believe it's 1-1/16", at least that's what I've always used and they fit great, never rounded one off, I see some places list those as metric nuts, but they're basically the same injector line fittings that have been used for years on trucks, tractors, etc. which I'm pretty sure are not metric but I could be wrong. Just put your big wrench on the connector tube and use your open end 3/4 on the fuel line. As long as you have good wrenches that aren't sloppy fitting you won't round anything over. You will need stubby wrenches for the rear most ones though. I tried to use flare wrenches the first time I did injector work, and while it seems like it would be better on the fittings, there's just not enough room to get them over the nuts especially when you get towards the back, an open end will slide on from the side and is just what you need.

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#4 ·
If you do go the crowsfoot route don't forget to determine proper adjusted torque. I just used open end 19mm and (3/4'' stubby) for mine. I went with goodntight on the fuel lines. On the feed tube nuts however I torqued twice. Once on install and once after a few heat cycles. 45ftlb both times.

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#5 ·
If you do go the crowsfoot route don't forget to determine proper adjusted torque. I just used open end 19mm and (3/4'' stubby) for mine. I went with goodntight on the fuel lines. On the feed tube nuts however I torqued twice. Once on install and once after a few heat cycles. 45ftlb both times.

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Yup def aware of the torque procedure, out straight changes the amount of force applied at the fastener (moment arm).
Not sure if there's going to be room to get in there with the foot @ 90*, so I'll likely just measure and do the math and decrease my torque by the proper percentage.

Not sure where you're getting your values from, but my FSM calls for 37 ft-lb at the injector tube nut (I'll be checking/re-torqueing that when the line is off) and 22 ft-lb at the line fittings...

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#6 ·
Agreed, FSM calls out 37.

My experience with talking to shops is that 37 tends to leak and was suggested to do 45. I did 45 and checked again after a few hundred miles and they were all loose. I was pretty shocked they were loose. I let my truck sit over night and re-torqued to 45 and they have been fine since.
 
#7 ·
Agreed, FSM calls out 37.

My experience with talking to shops is that 37 tends to leak and was suggested to do 45. I did 45 and checked again after a few hundred miles and they were all loose. I was pretty shocked they were loose. I let my truck sit over night and re-torqued to 45 and they have been fine since.
37 is for the feed tube, not the injector line fittings. The line fittings (19mm) are 22 ft-lb. The feed tube nut into the head is a 24mm nut.

Was your leak from the feed tube seating or the actual high pressure line fitting that attaches to that feed tube?
 
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#11 ·
After digging some more here and on a couple other google searches, I found this thread which has very good info:


There are 2 styles of feed tubes. One has 2 ball detents and works for the 03-07 trucks. One has a "slot" and is the updated version for the 6.7 trucks.

Cummins superseded the 2 different part numbers with 1 part number, that is supposed to work with both style injectors. The "new" updated tube has a larger outlet diameter (I think I saw .075" vs .120"), as well as makes use of a different material. As well there might be a slightly different sealing surface angle on the 2 different versions even though they are said to work with both engines...take that how you want.

It goes back and forth about if the new single part number works with both 5.9 and 6.7 injectors. Some say yeah, no problem, some say stick with the tube designed for your year (as you can still get the "old" style from Bosch).

There is no torque update to original tube...37 ft-lb. The new tubes, although I haven't found any viable proof, says they are meant to handle more torque (sealing surface is slightly different) in the 41-45 ft-lb range. But again, no one provides any evidence. I have not found anything on the HP lines that need more than 22 ft-lb. The FSM states that the other set of HP lines (pump to rail) requires 27 ft-lb (spec sheet above) but these lines are what feed the rail, not from the rail to the head, so they are not being touched.

I'm all ears though if someone can provide some concrete proof one way or the other. But for me, I'll be sticking with the FSM specs. When it's time to change injectors, I'll go with whichever tubes are recommended for the injectors I purchase from BBI.
 
#12 ·
I bought my injectors & feed tubes directly from BBI in Europe (Martin). The new feed tubes are the 2 ball detents, the same as the originals.
 
#14 ·
seems to me you could make that wrench from a quality box end wrench. i had to do that to install a high flow exhaust manifold on an audi tt engine. had to use a nut that took a 12mm wrench on the studs out of the head vs the 13mm sized nut that was oem. in that case i ground the area on the outside of the box end until it fit on the bolt and cleared the runner.

could do something similar for the hold down nut with a 12 pt box end...
 
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#15 ·
IMO, even with a crowfoot socket, you can't get to all 6 line nuts and it's tough to get an accurate torque reading with the crowfoot socket on the torque wrench.

What I do is use the crowfoot and torque wrench on #1. Then loosen it and get a feel for the torque by hand with a combination wrench and then tighten the other 5 by hand.

45 ft lbs is ton IMO for the connector tube nuts. Even 37 ft lbs feels like too much.
There is no need to crank those connector tube nuts down so tight.
 
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