Main Fuel Hose Size

Topic: Main Fuel Hose Size (Read 1522 times) previous topic - next topic

Main Fuel Hose Size

August 16, 2014, 11:45:37 pm

Can someone tell me the size of the main engine feed and return fuel hose on a 97' U320? I am getting ready to replace the hose and want to order Trident 365 A1 Barrier hose. I am up and running now and don't want to take things apart until I have all the parts. I am just unsure of what size...
Also if anyone is planning this project my cost on the Trident Series 365 Barrier A1 Marine Fuel Hose, 5/8" x 50' Box is $90.54 with free shipping.

Trident "Barrier Lined" Type A1-15 Marine Fuel Hose #365
Trident Barrier Lined A1-15 Fuel Hose (Distribution, Return, Vent, and Transfer) for both gasoline (petrol) and diesel (including alcohol blends). Exceeds ABYC H-24 & H-33, SAE J1527, ISO 7840, & USCG Type A1; and is NMMA Type Accepted & CE certified. It is also compliant with CARB Regulations. Built with best fuel, fire and age resistant formulation, 2 spiral reinforcement and unique "Barrier Liner" on inside surface of tube so fuel is not in direct contact with rubber. Provides extraordinary resistance to fuel permeation and aging, as well as fire, heat, cold, and ozone. Also good
Bend-ability.
5 YEAR WARRANTY

Thanks
Ted

Re: Main Fuel Hose Size

Reply #1 – August 18, 2014, 01:22:02 am

I don't know which size engine you have or if that even affects which size fuel line FT ran but my 8.3 liter engine had a 5/8" ID hose for the supply line. Return line was 3/8" ID hose.

There are a few threads with additional information-

Old Fuel Lines

Group buy Parker HTFL fuel line?

Re: Main Fuel Hose Size

Reply #2 – August 18, 2014, 08:29:51 pm

Thanks for the links Robert, I had searched "Fuel hose" to no avail... Interesting back story... Foretravel Parts told me the hose per built sheet is 3/8 x 34'..... I don't think so.. #10 fittings tell me 5/8.....

Cheers
Ted

Re: Main Fuel Hose Size

Reply #3 – August 18, 2014, 09:24:07 pm

Ted:
On my 1999 U320 with a Cummins M11 ISM the supply line is 5/8 and the return line is 1/2. The aquahot and generator are all 3/8.

The Trident A1 fuel line was also my choice. It is tough and the inner liner makes it very difficult to kink. The price is also very reasonable. When installing the old fittings into the new fuel line it is necessary to immerse the line in very hot water for several minutes before pressing them in.

Replacing all the lines is a pretty tough job. It was very difficult to remove the fiberglass covers from the tank and very difficult removing the tank. I posted some pictures and information in the following link. There is also a step 2 and step 3.

First step to fuel line replacement (Removing tank covers)

Enjoy the challenge
Jason

Re: Main Fuel Hose Size

Reply #4 – August 20, 2014, 12:05:22 am

Thanks Jason, I am on the fence on what tube/hose to use.. Coming from a marine background I am leaning to the Trident barrier hose, thou 1/2" nylon HTFT tube would be a lot easier to feed thru... Also coming from the marine side and dealing with floor and deck hatches I am going to take up the carpet and access the tank thru the floor, building a removable hatch, and not remove the fuel tank. I hate not being able to get to fitting and this way I will be able to get to the tank fitting at a later date if needed.... I will let you know how this works out....

Cheers

Ted

Re: Main Fuel Hose Size

Reply #5 – August 20, 2014, 11:27:55 am

Ted, I like your thinking on access to tank. I have been pondering this fuel issue and will look at location/ difficulty at getting to these connectors before going any further. I still am considering an external route from tank to engine via the underbelly in a channel protection bolted to framing. I will address this install after our winter trips as so far no signs of problems with our lines.
JohnH

Re: Main Fuel Hose Size

Reply #6 – August 20, 2014, 12:06:54 pm

I don't remember the details, but there was a write up by a forum member awhile back who did the access hatch in the floor for fuel line fitting access. I considered this option before going to the factory, but really would not be an invisible solution unless covered with carpet since the area where access is needed (on our coach, at least...) is right in front of the couch in the walk way. Ultimately, I was happy to trade money for time to have FOT do it...
Don

Quote from: Ted H – August 20, 2014, 12:05:22 am

... Also coming from the marine side and dealing with floor and deck hatches I am going to take up the carpet and access the tank thru the floor, building a removable hatch, and not remove the fuel tank. I hate not being able to get to fitting and this way I will be able to get to the tank fitting at a later date if needed.... I will let you know how this works out....

Cheers

Ted

Re: Main Fuel Hose Size

Reply #7 – August 20, 2014, 12:35:06 pm

Howdy Don,

Quote from: acousticart – August 20, 2014, 12:06:54 pm

I don't remember the details, but there was a write up by a forum member awhile back who did the access hatch in the floor for fuel line fitting access.

This may be the string: Replacing Generator fuel line on '99 U320
Good Luck, Dave A

Re: Main Fuel Hose Size

Reply #8 – August 20, 2014, 09:22:47 pm

Yep, that was me and we did put a hole in the floor. A lot easier then trying to remove the fuel tank. Getting the side panels off was enough pain.
Any questions, just drop me a note.

Re: Main Fuel Hose Size

Reply #9 – August 20, 2014, 11:18:02 pm

Dave & Dick.. thanks for the link.... this will work for me.. Replacing the carpet is on the todo list anyway....
Cheers
Ted

Re: Main Fuel Hose Size

Reply #10 – August 23, 2014, 07:49:52 pm

I have been thinking about this subject for a while now and have a question that hopefully the members who have done a fuel hose replacement should be able to shed some light on.
Was the breakdown of original hoses mainly at the connection ends(fittings) or were there cracks/damage to other sections of lines?
If it was only at the fittings then why not wrap that section with silicone (rescue) tape to stop air intrusion than replacing all the line. Or, cut the first 12" off line and add a new piece. This would then only require access to the start and finish areas for either "fix"???
Hopefully many will comment.
JohnH

Re: Main Fuel Hose Size

Reply #11 – August 23, 2014, 09:50:57 pm

I've been thinking about this too. I had my coach at Cummins last week and they inspected the fuel lines. They said they were good, no signs of fatigue or cracks and suggested inspecting them every year. Probably a good idea. The service mgr said fuel lines degrade with time and temp. I'm just over 61,000 miles. The coach has been stored indoors since it was new. What makes the lines age? Why are some 2001 coaches having (need to have) their lines replaced? Is it milage related?

When it is time it will get done. Just not sure when that will be and why it seems to be different from one coach to another.

Always something to think about. Always something to learn.

Roger

Re: Main Fuel Hose Size

Reply #12 – August 23, 2014, 11:19:46 pm

Roger, I doubt Cummins inspected the top of tank and that to me seems to be the main area that leaks have been found (or am I wrong?)
I noticed a year ago when I had genset pulled out and got under in the pit looking for that air leak from step slide cylinder, that the lines to gen at fittingslooked like they may be getting to be at the fail stage. I wrapped the ends with that Silicone tape pulling it as hard as I could so I got a good seal overwrap right onto fitting. This was done as a precaution because we do not use it for power but just in case. That to me had me thinking of this question as the hose looked good along what I could see.
As I mentioned I hope all who have been there will answer my question.
Don, what was your observation as to failing fuel lines??
JohnH

Re: Main Fuel Hose Size

Reply #13 – August 24, 2014, 12:03:10 am

I wrote about my findings in one of the other fuel line topics.

You won't be able to see if the hose sections on top of the tank are bad until the tank has been pulled out and this was the worst area for degradation of the fuel lines. No air flow and hot fuel being returned to the tank clearly created a situation that the fuel lines didn't like.

The next worst area would have been the connections to the primary fuel filter followed by the hose going between primary fuel filter and the lift pump. Luckily, these sections are clearly visible with a little crawling around under the coach and spraying everything off with a hose.

For the generator, its clear that the hose inside the gen compartment is subjected to lots of heat and if it starts to go, you should probably replace everything. The previous owner of my FT had cut off the bad section of line and coupled it to a new section. However, he had also tried to yank the line to get as much slack as possible from the excess on top of the tank. This is a bad idea. His pulling had kinked and collapsed the fuel line so leave the slack where it is if you decide to splice extra line onto the existing.

Having said all of that, the sections that were run through the chase seemed in near perfect condition. Despite that, I would personally pull all new lines if I found any signs of deterioration.

Re: Main Fuel Hose Size

Reply #14 – August 24, 2014, 12:19:19 am

I am pretty sure they didn't (couldn't) see the lines above the fuel tank but they did look at the lines in the engine compartment and around the gen set. They looked OK.

I wonder if you can use one of those remote video viewers with the camera on a flexible wand to inspect the lines at the top of the tank. Pulling the tank for a look-see is a lot of work.

Lots of folks have replaced lines. What lead them to do this? Where did they find deterioration before and after the lines were pulled?. A couple thousand $ I am sure. Why and when are the questions.

Roger

Re: Main Fuel Hose Size

Reply #15 – August 24, 2014, 12:32:34 am

The why and when was the generator. It would start and stop after 30 seconds or so. this was after the fuel had run under ¼ tank according to the gage. Filling the tank didn't help... diagnosed when a bucket of fuel kept the gen running smoothly. Turns out the fuel gage probable wasn't accurate. A full tank only made the gage go up to ⅝. Had new sender put in while doing the fuel lines. Up to that point, there were no indications of any problems with the main engine. Looking at the main fuel lines after they were pulled from the coach, cracking was easy to see all up and down the length. It wouldn't have been long before it would have been a roadside adventure...
Don

Quote from: Home2fromHastings – August 24, 2014, 12:19:19 am

Lots of folks have replaced lines. What lead them to do this? Where did they find deterioration before and after the lines were pulled?. A couple thousand $ I am sure. Why and when are the questions.

Roger

Re: Main Fuel Hose Size

Reply #16 – August 24, 2014, 12:34:30 am

There is no way you can tell how bad the hoses on top of the tank are unless you pull the tank out. There is just so much stuff on top of the tank and that passes through the chase that you really can't see anything. I was surprised when I pulled the tank and found the Cummins supply line actually leaking fuel onto the top of the tank and this was at 16 years and 95,000 miles.

I based my decision on having problems with the generator supply line and knew that if I was pulling the tank, I was only doing it once. After very close checking of the Cummins lines in the engine bay, it became clear that they were probably not going to last too much longer either.

See the pictures here for what the damage looks like-

When new fuel lines?

Look specifically at the areas around connectors at the primary fuel filter and the lift pump. Take some wet rags and clean up those sections well to get a good look.

Re: Main Fuel Hose Size

Reply #17 – August 24, 2014, 03:44:21 am

Cheap borescopes are now available at any tool place or harbor freight. You can stick one up on top of the tank and check out the fuel lines.

Re: Main Fuel Hose Size

Reply #18 – August 24, 2014, 09:02:10 am

My findings were the same as Robert and Don. It all started with a fuel line leak at the generator in the middle of the desert in Quartzsite. A temporary fix was made by splicing. Looking at the rest of the fuel lines there was lots of cracks in the lines at the connections where the fuel line was forced onto the nipple as well as cracks at sharp bends. After pulling and replacing all the lines the straight runs through the channel seemed fine. I include a few photos showing these stress cracks. It seems that stress causes the line to crack. I did not want possibility engine problems because of bad fuel lines and having to deal with it on the road. Because Foretravel thought those lines would last forever and put the intake connections in the center of the tank this job becomes much more difficult so once you start replacing lines it is best to change them all. I believe splicing can be a temporary fix but am not sure if the old lines will start splitting at the splice.

Re: Main Fuel Hose Size

Reply #19 – August 24, 2014, 11:47:58 am

So, in answer to my question it does seem that the gen lines have been mostly the first sign of leaking and I put that down to the closeness of heat coming from genset. I also think that many people run their Generators while travelling for A/C, so the combination of engine plus outside air temps may increase the breakdown of hosing. We have not had this problem and I guess as we do not use the Genset at all this may be why we are ok so far. Our coach seems to be in the same time frame as many that have had this problem too. I also feel that in most cases once the fuel line is cut for fittings to be applied that maybe the cross section could be comprimised in some way, and add heat to the equation you get a domino effect???
I think I will plan to do that cutting out of floor above tank and take a peek there, along with the filter and pump area fittings to determine what I am going to do. Luckily having the ability to walk under the engine area etc makes this a simple exercise.
Please keep your findings coming if you have gone thru this (replacement) of lines.
JohnH

Re: Main Fuel Hose Size

Reply #20 – August 24, 2014, 01:59:24 pm

So best advice is to keep a close watch on lines for signs of cracking or leaks. We are up to about 200 hours on our generator so like John I see no signs of fuel line problems so far either at the generator or engine end. But I will keep an eye on it.

Thanks for the detail descriptions and pictures. They help understand what to look for.

Roger

Re: Main Fuel Hose Size

Reply #21 – August 24, 2014, 02:34:05 pm

Okay so here's my take on the fuel line issues.. I think the problem is related to two things. First the outer layer what I call the wrapping, has deteriorated with all the cracks we see. In years past this was not an issue as it only went as far as the cloth between the outer wrapping and the inter rubber hose. The second issue is ULSF ( ultra low sulfur fuel) that attacks the inter-rubber hose allowing the fuel to thus get to the outer wrapping cracks creating the fuel leaks which we now see. Modern day fuel lines are no longer rubber hose. They are nylon tube, either what is called barrier tube.. A hose that looks like what we have now, but with a inner nylon tube in place of the rubber that we have or nylon tube like Parker HTFL. Some time in the future anyone with rubber hose fuel lines will eventually face the issue of changing them out to nylon. JMHO..

Re: Main Fuel Hose Size

Reply #22 – August 24, 2014, 05:10:12 pm

So Ted if no fuel is going thru the gen line it will not break up at the same rate as someone 's who uses it a lot, and, as I use a lot of non ULS fuel (ie mexico + I bring 10 galls back in cans to mix with ULS) then again my lines will not show the cracking at the same rate as others.
Makes sense.
I just took off one side of Tank cover (Pass' end) and had a good look at lines for return. No problems there. Tank top dry and shining a good beam of light to Pick up lines with all other tubes etc lifted up away from fuel ones I did not see anything except a tiny crack about 1/4" long on the larger one. Away from fittings is good,so, my next line of attack is to cut away the floor and make a 12x12" opening right over the pick up fuel fittings and maybe tape the ends as I mentioned earlier. I have yet to check filter ends etc.
Taking this end panel off allowed me to fix a opening behind the air bag in framing so as road water etc does not get into this front bay. I also made a shelf to hold my fuel additives and spare oils.
JohnH

Re: Main Fuel Hose Size

Reply #23 – August 27, 2014, 05:31:21 pm

Well decided today to cut out the ply floor and look at those fuel line connections on top of tank. You can see how I did it (very simple). The first 2 pics are the location and after done. The next one is main fuel line and it does have a very small fine crack about 3/8" long in 2 places but is dry and top of tank too. The last one is gen line so I think this confirms Ted H's and mine thoughts on the ULS being an issue. No cracks in this line as I do not use the genset.
So, I am going to wrap the main line with "rescue tape" along with the gen one and seal the floor back up. After 13 yrs of off and on use and all this is what happens makes me think it will last a good few more years. If not I know were the hole is so I can remove it again !!! You sure have to be careful cutting thru the fibreglass skin as those air lines are right up against the underfloor. I got a scratch on one of the 3/8 hoses but that is it. I will wrap that too for safety and strength.
JohnH

Re: Main Fuel Hose Size

Reply #24 – August 27, 2014, 06:19:25 pm

A brave heart. But it sure beats pulling the tank out.

Do you have enough dimensions so that someone else could do the same? Looks like my tank is in the same location as yours, first bay behind the steer wheels.

Roger

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