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Topic: Fuel Leak on ISC350, what is this fuel line? (Read 622 times) previous topic - next topic

Fuel Leak on ISC350, what is this fuel line?

I started the FT yesterday and noticed a fuel leak. ISC350 8.3  It is coming from 1-2 washers adjacent to a banjo bolt. Photo below.  This is photo is from the passenger side with the bed raised and looking down.  The

Looking at the parts diagram, I am unsure what the name of this fuel line is or what it is, maybe a return line? I put a wrench on it and it was loose, so I tightened it up , no more leaking. However, I do want to get some sealing washers to be proactive.

What is this tube name and what is it used for? It has a 15mm banjo bolt, does anyone know the washer size? From what I can tell, there are a few different ones, maybe not a bad idea to get spares of all but I am unsure what size this is.

3918191 12 mm
3918192 14mm
3918190 10 mm

Possible parts
Fuel drain - https://mart.cummins.com/imagelibrary/data/assetfiles/0057274.pdf
The tube looks like the one at the bottom here https://parts.cummins.com/gateway/api/IACDataServices/graphics/rtgraphics/english/parts/ft/9/ft941ge.png

Jason
2000 U295 36' Non-slide  ISC350

Re: Fuel Leak on ISC350, what is this fuel line?

Reply #1 –
Good question! Here is a flow diagram for the ISC... Looks like the return line back to the tank after going through the manifold that is part of the lift pump assy.
Don
Edit: I believe that #10 on the IPB is the line in your picture.
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Fuel Leak on ISC350, what is this fuel line?

Reply #2 –
I think FASS fuel systems makes a kit to replace the Banjo fittings
1999 36 ft U270
Build 5465

Re: Fuel Leak on ISC350, what is this fuel line?

Reply #3 –
Any cummins dealer will have those Fuel washer if it tightened up it probably ok just vibrated loose hadn't been tightened properly from the start
Rick & Hilda looking forward to full- timing one day for now couple of months at a time
1999 U270 3602
Built number  5530.  Feb 1999            Motorcade  number 18438
8.3 Cummins Allison six speed with brake  retarder
Purchased Nov 28 2019

Re: Fuel Leak on ISC350, what is this fuel line?

Reply #4 –
Thanks all. I recently replaced similar washers on the back of my fuel bowl on my 5.9, so I am familiar with them. Unfortunately,  they are not always the easiest to get. Yea, I can see this rattling loose with as much vibration as this makes.
Jason
2000 U295 36' Non-slide  ISC350

Re: Fuel Leak on ISC350, what is this fuel line?

Reply #5 –
Assuming that the banjo fitting washers are copper.

Copper work hardens (loss of ability to change shape) under strain. I have had very good luck reusing copper washers by annealing them, lay the washer on a flat surface, fire up the propane torch, heat the copper until it glows, let the copper cool without help.

Tim
Tim Dianics
Pam Sapienza
Vader PupZilla Labrador Canine Beast (AKA Pup)
Columbia, MO
1996 U320 4000
2021 Jeep Gladiator, Diesel

Re: Fuel Leak on ISC350, what is this fuel line?

Reply #6 –
Quote from: TGordon –
Assuming that the banjo fitting washers are copper.

Copper work hardens (loss of ability to change shape) under strain. I have had very good luck reusing copper washers by annealing them, lay the washer on a flat surface, fire up the propane torch, heat the copper until it glows, let the copper cool without help.

Tim

The same thing I have to do each time I reuse the copper head gaskets for my race engine.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Fuel Leak on ISC350, what is this fuel line?

Reply #7 –
8mm,10mm,12mm,14 mm Qty 10 each Banjo Bolt Fuel Sealing Washers For Cummins...

I ordered this kit yesterday. It's been on my todo list to get some extra washers, and when I started putting the part numbers in on eBay, this came up. Cheap insurance for those with a Cummins, IMO. When I had to get some for my 5.9, DW had to go to 2 different dealers to get them, so they're not as easy to get, and probably harder in a remote/smaller town.

HTH, no affiliation, yati,yati.....
Jason
2000 U295 36' Non-slide  ISC350

Re: Fuel Leak on ISC350, what is this fuel line?

Reply #8 –
If you don't have an account yet, set up a free account with Cummins QuickServe.  Here you can put in your engine serial number and look up all the parts for it online.

Cummins Inc. :: QuickServe Online
Keith
2003 U320 38' #6197

Re: Fuel Leak on ISC350, what is this fuel line?

Reply #9 –
FYI for those with the 8.3 Cummins.  I had a fuel leak in the metal fuel line as shown in the diagram below.  If your engine has that same (original) metal tube setup, might be worth your time to remove that clamp and check for any abrasion damage between the clamp and the fuel line.  Link to my repair thread:

SAFETY ALERT: C8.3 Fuel Leak

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"