Broken metal fuel line

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Broken metal fuel line

March 12, 2019, 12:06:02 am

Today we completed a five day trip from Nac to Tucson. Until today, a problem-free trip. But when we arrived in front of our house and I bent down to disconnect the coach from our Jeep, I saw a liquid pouring onto the ground from the right side of the engine. It was diesel fuel. I quickly drove the coach into our driveway (a fairly large graveled area) and turned off the engine. With the help of a couple of friends, we were able to see that the leak was coming from a cracked metal fuel line at the aft end of the fuel pump. I took some pics and sent them to Cummins Tucson and they informed me that it is likely the metal line running from the lift pump to the fuel pump. We have the ISC350 engine.

Has anyone else had a failure like this? It is my impression that these lines rarely fail. I recently had some work done on the engine in Nac and many of the fuel lines were removed to find an oil leak behind the gear cover on the right side. Of course, I am wondering if that service somehow lead to this problem.

Does anyone have a recommendation for a mobile diesel mechanic in the Tucson area? The local Cummins shop does not have a mobile service and I would have to tow the coach into them to have it repaired.

Yes, we were very lucky that this leak did not develop in some remote location between Nac and here. And that there was not a fire! It was very windy today on our trip from Willcox, AZ to Tucson, but the coach handled well (gusts to 30mph were predicted).

Re: Broken metal fuel line

Reply #1 – March 12, 2019, 12:24:33 am

Had a similar leak from metal line 6 months ago. My engine is probably somewhat different, so might not be the same fuel line.

SAFETY ALERT: C8.3 Fuel Leak

Re: Broken metal fuel line

Reply #2 – March 12, 2019, 12:38:32 am

If you can pinpoint the leak,get a hose clamp and a piece of rubber hose and make a patch,will get you going.

Re: Broken metal fuel line

Reply #3 – March 12, 2019, 10:05:16 am

Quite a coincidence Chuck, ours developed a leak in the exact same place on our last trip. Discovered it at a rest area in South Carolina on I26. Ours was missing that clamp support (some mechanic or PO forgot to replace it while doing some previous work I suppose) the fuel line had rubbed against the bolt head for the clamp until it developed a pinhole. I've put over 30K miles on it so it took it a while to wear through. I just happened to have a short piece of 3/8 fuel line and some hose clamps in the tool box. Split the hose slipped it over the hole and put clamps over it. Didn't stop it completely but slowed it to a slow drip until I could finish our trip to Asheville (about 2-1/2 hrs). While at camp I removed the line, cut the bad section out of the tube, bought some 3/8 fuel line and six clamps. Slipped the new line over the tube and triple clamped each side. No more leak! Drove it home later that week (500 miles) got home with no problems and no leaks. Still have to order a new replacement line from Arizona Diesel and get it changed out. A Project for the next few weeks.

Re: Broken metal fuel line

Reply #4 – March 12, 2019, 10:56:26 am

Chuck... I think my leak is different from those described for the C8.3 engines above. Mine is at the banjo fitting coming into the fuel pump. I have never installed a banjo fitting. Are these torqued to a specific standard or just tightened until they don't leak?

John, thanks for the suggestion regarding a temporary fix.

George

Re: Broken metal fuel line

Reply #5 – March 12, 2019, 11:26:31 am

The banjo may have some crush washers/gaskets of some kind. They can leak . They also tend to rotate when tightened a little and can break the line due to bending. You may have to hold the banjo fitting itself with channel lock plyers to stop it from rotating.
Tighten it a few times and get a feel for how much it wants to rotate , push it against the rotation and tighten it.

Re: Broken metal fuel line

Reply #6 – March 12, 2019, 11:42:42 am

If you break a banjo fitting you need a new crush washer to re-install it.

Re: Broken metal fuel line

Reply #7 – March 12, 2019, 11:46:30 am

Quote from: George Hatfield – March 12, 2019, 10:56:26 am

Chuck... I think my leak is different from those described for the C8.3 engines above. Mine is at the banjo fitting coming into the fuel pump. I have never installed a banjo fitting. Are these torqued to a specific standard or just tightened until they don't leak?

I have removed and installed several of the banjo fittings on my engine, when replacing the overflow valve and installing fuel pressure gauge, plus when I replaced the leaking fuel line. I always use new washers on those fittings. I just snug the retaining bolt up with a short wrench until it "feels" pretty tight (to me). Have not had any of them leak, or even seep a little. Sorry - I don't have a recommended torque setting. I think it would be difficult to get a torque wrench into that area of the engine compartment (at the right angle).

All the fuel lines and fittings that are upstream of the injection pump are part of the "low pressure" fuel circuit. The pressure they see is determined by two factors: how much pressure the lift pump (transfer pump) puts out, and at what pressure the overflow valve opens. The pressure in these lines could run anywhere from zero psi (with a faulty/broken overflow valve) to maybe around 40-50 psi (I'm just guessing on the max possible lift pump deadhead pressure with overflow valve stuck completely closed).

What I'm saying is, the banjo fittings don't see any really high fuel pressure, so don't need to be super tight.

Re: Broken metal fuel line

Reply #8 – March 12, 2019, 12:06:54 pm

Glad you got home safe George. Now this makes me want to go out to check our lines as same engine. Will have to make a note to do this and put in dash.
JohnH

Re: Broken metal fuel line

Reply #9 – March 12, 2019, 01:04:23 pm

I called Coachnet. Very helpful. They have a contract with a mobile diesel service in Tucson and they expect the line can be fixed today. So hopefully a tow will not be necessary. After it is driveable I will be taking it to Cummins Tucson to have all the fuel lines on the engine checked to make sure there are not any additional problems waiting to happen. The is not the first post-service problem I have discovered.

George

Re: Broken metal fuel line

Reply #10 – March 12, 2019, 04:55:56 pm

The mechanic from Mobile Maintenace and Towing (Tow Service Tuscon | Mobile Maintenance and Towing LLC) came and removed the fuel line so he could get a replacement from Cummins. They could not identify the part from my photos and the engine ID number. I think you can see the crack in the line in the attached pic. Shawn, the mechanic, thinks it is just a vibration induced crack. There is only one bracket to hold the line and it is near the lift pump. So perhaps this break was not due to recent service. I guess we will never know.

Update: Cummins just called. That particular line has been discontinued, but they found one on the east coast and it will be here before the end of the week.

Re: Broken metal fuel line

Reply #11 – March 12, 2019, 05:50:03 pm

For what it's worth, we have similar looking lines on Duetz power units for use on irrigation pumps. When we have a stress crack like that, we clean it up real good and braze it. Might be worth a try. We never had one recrack where we repaired it.

Re: Broken metal fuel line

Reply #12 – March 12, 2019, 06:01:08 pm

One other thing, the hollow bolt that goes through the end of that line was brass washers on both sides. Don't forget them.

Re: Broken metal fuel line

Reply #13 – March 12, 2019, 06:39:32 pm

Quote from: Forewheelers – March 12, 2019, 06:01:08 pm

One other thing, the hollow bolt that goes through the end of that line was brass washers on both sides. Don't forget them.

The washers for banjo fittings are copper, softer than brass.
Copper work-hardens and must be annealed before reuse (heat with a propane torch until it glows and let cool).
I have not had a failure reusing an annealed copper washer.

Tim

Re: Broken metal fuel line

Reply #14 – March 12, 2019, 07:31:05 pm

Some thing to consider with these type of cracked pipes (and hoses), is that if the subject pipe/hose is hard fastened to the chassis close to the engine and there isn't much room for it to work, it will work harden over time as the engine torques and will crack in the work hardened area. You may want to check it and make sure that the pipe/hose has plenty of room to move as the engine torques. I have replaced hoses with a slightly longer one so that it would have the needed room. Have a great day ---- Fritz

Re: Broken metal fuel line

Reply #15 – March 12, 2019, 09:50:16 pm

When I searched for the replacement part for mine through Cummins quick Serve using the engine serial number the new replacement was braided stainless steel covered flexible hose in the mid section instead of a solid steel line like the original. Maybe this has been an issue on these engines?

Re: Broken metal fuel line

Reply #16 – March 13, 2019, 05:58:49 pm

NEVER tow if there is ANY other option, even if it takes more time to make a temporary fix. . . Towing may cause new unforeseen problems.

Re: Broken metal fuel line

Reply #17 – March 13, 2019, 07:19:54 pm

George,check out this site,Russell Fuel fittings,may have a solution.

Re: Broken metal fuel line

Reply #18 – March 13, 2019, 07:28:56 pm

These engines shake and change size with heat. Any solid line will eventually fail. Adding any vibration tolerant fuel line seems like a good idea.
The Cat 3208 boat guys carry spare injector lines.

Re: Broken metal fuel line

Reply #19 – March 20, 2019, 12:32:49 am

The fuel line arrived today and the mechanic from Mobile Maintenance installed it. It took a couple of hours since he had to remove several other fuel lines to get it in. Last week he had cut the old line out so we could get it ordered. They did not get the line from Cummins since it had been discontinued. According to the shipping label, it came from S. R. Sales of Waukesha, WI. Evidently, they had about 70 of those lines. I'll confirm the source in case anyone else wants to get one.

One positive thing about this experience was Coachnet. They were very helpful in finding a mobile mechanic in Tucson. The guy that did the work seemed very competent and was a very nice person. I really don't think I will have any problems with his work.

Re: Broken metal fuel line

Reply #20 – March 20, 2019, 12:38:15 am

Take the old line and find a shop that can salvage the ends and have them make you a flexible line,may work in more then one spot.
If anything keep the ends so you can match them up at a shop.

Re: Broken metal fuel line

Reply #21 – March 20, 2019, 11:38:09 am

George, if you do find out who sold it maybe let me know as I should get one just for "in case"
JohnH

Re: Broken metal fuel line

Reply #22 – March 20, 2019, 07:31:50 pm

Hopefully, this is my last post on this topic. The last job I had was to clean the insulating blanket in the engine compartment. Needless to say, it was covered in diesel and dirt. Since diesel fuel has a boiling point 2-3x that of water, it would take quite a while for it to leave on its own. So I used some Gunk Original engine degreaser followed by hose water and then used Tuff Stuff foam and several rags to clean off the remaining grime. I was amazed at how clean it got. The top was the hardest to clean and impossible too image.

Re: Broken metal fuel line

Reply #23 – March 20, 2019, 11:36:02 pm

Wow, nice and clean George, I am going to have to clean mine now as cannot have mine dirty after seeing that one.
JohnH

Re: Broken metal fuel line

Reply #24 – March 21, 2019, 10:18:47 am

Great to hear that Coach Net took care of you and you are back on the trail again!

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