Fuel line replacement

Topic: Fuel line replacement (Read 1508 times) previous topic - next topic

Fuel line replacement

June 24, 2025, 09:24:24 pm

I have been putting off replacing fuel lines for a year. I have searched the forum on the subject and studied all that is available and I still do not feel competent enough to proceed further. I have a 1999 u320 40' with slide. I have found the threads with same year or close that are without slide or 36' and none have addressed the wall structure drivers side that encloses the fuel tank. I have defueled the fuel tank removed the curb side rocker panel basement door and hinge structure removed the 3 bolts securing the tank to the floor. On the driver side the fiberglass cover cannot be removed without cutting because of the wall structure under the slide prevents access. Picture attached. I cut the bottom 3 " of the fiber glass panel off to access the bottom of the fuel tank for lifting the tank after removing the 3 bolts. I tried to raise the tank to slip a 1/2" steel tube to act as a roller but tank seems to not be able to go any high. Curb side I was able to raise the tank just enough for clearance of the drain plug. There seems to be so much pressure on the top of the tank from all the hoses jammed on the front side of tank that it prevents the tank from being raised any higher and being free to slide out. If I were able to slide the tank out I am not sure I could get it back in. It would require winching it out with a come along or similar. For those of you who have accomplished this task did the tank come out easy? Did you have such a tight fit that it required a winch to get it out?
Has any one changed the hoses by access the tank and hose fittings by cutting a hole in the floor above? I am stuck and my tank is stuck. I need advise as to what to do now? I would welcome a phone call from anybody that can shed light or give me an idea how to proceed.
Daniel 7195100092

Re: Fuel line replacement

Reply #1 – June 25, 2025, 06:16:47 am

Take the molding piece above the bay off an you will see the screws that hold the trim around the bay on, then you can take that off. That piece the tank is sitting on will slide out. And then the tank will have room to slide out.

Re: Fuel line replacement

Reply #2 – June 25, 2025, 07:20:04 pm

If you are referring to the drivers side, it is not possible. I have attached photos to show drivers side wall under the slide out. It is a welded structure . There is no access. Also slide lock at the top of right side of tank holds the fiberglass cover in place so you cannot take cover off of the fuel fill tube. My guess is when this coach was manufactured since it was the first year for a slide , the fuel tank was the first thing installed in the chassis. Then everything else was built around it. Slide out was built separate and last in the sequence to be installed. Since I do not have access to drivers side of tank to push tank out, I hesitate to take tank it out. On the passenger side I have removed everything that prevents the tank from being able to slide out. I have tank resting on a 3/4" piece of conduit to act as a roller. However the tank will not raise any higher account it is pushed tight against the old hoses and the bay ceiling. It is so tight I fear if I used a winch or come-a-along to get the tank out I would not be able to get it back in therefore thoughts of changing directions and cutting hole in the coach living room floor to access the hoses from on top. Thoughts? Suggestions?
Quote Selected

Re: Fuel line replacement

Reply #3 – June 25, 2025, 07:46:25 pm

Daniel,

Those coaches with that strongback are the hardest to change out the fuel lines. Here is a couple of things that might help you out.

1. Are you sure that you have the tank high enough for the drain plug to clear the floor.
2. That vanity panel on the drivers side most likely was glued to the tank. If this is the case I have had to destroy that panel to get the tank out. That side will need to slide on the floor. Once out you should find 3 or 4 pieces of rubber that the tank sets on.
3. You may have to install 2 of those hold down bolts in backwards to have a place to hook a rope to and a come-a-long to the rope and pull gently.
4. Yes there has been a member or 2 that cut an access hole in the floor above the tank.

Mike

Re: Fuel line replacement

Reply #4 – June 25, 2025, 09:14:48 pm

Mike
Thank you for your reply. You give me the courage to proceed. The drain plug is clear but not by much. The vanity panel drivers side was held on by 6 screws that I was able to remove and it is loose but no room to remove. Thank you telling me that some have destroyed that panel. As you can see from the photo I did cut the bottom off with a smile. I did see a couple of pads underside when I peeked with a scope. I am not sure what I might encounter if I did cut a hole in the floor but may have to do that to get tank back in once removed. I did consider using the hold down holes as you advised to pull tank out. Key word is gently. Not sure if that is possible. I will probably get a nylon strap to feed through the holes to make a harness to pull with come-a-along first. Many thanks for the advice. More to follow.
Daniel

Re: Fuel line replacement

Reply #5 – June 25, 2025, 10:12:22 pm

You may need a piece of 1X2 to slide on top of the tank from the passengers side to be able to lift/pry the hose bundle up/over the tank fittings that are laying down in between the fittings now. I know that sounds strange but once you get the tank out you will see what I am talking about.

Once you have the tank out you can get up in the belly of the beast and move, wiggle, or pry the hoses around to help make room that you don't have now, even a 1/2" is a bunch here. Once you start back you will need to build a wooden ramp/filler piece to be able to get the tank back in without getting the hoses hung up. I will hunt around and see if I ever posted a pic. of this part.

Mike

Re: Fuel line replacement

Reply #6 – June 25, 2025, 10:53:11 pm

Looks like you're in a building. You may be able to use a bottle jack on it's side pressing against a wooden block along the bottom of the tank from the drivers side. You might place a length of 6x6 against the building wall to spread out the force of the jack. It seems like that would provide a very controllable force and would be easier than trying to winch from the passenger side. Just my 2 cents. Your pictures make me cringe... and I thought my coach was impossible to work on.

Re: Fuel line replacement

Reply #7 – June 25, 2025, 11:18:14 pm

Bottle jack is a great idea. I have aircraft Jacks with 2 foot rams. I am in an airplane hangar but not close to a wall or upright to push against. I do have a skid steer that I can position to push against tho. Your 2 cents turned to gold. Many thanks.

Re: Fuel line replacement

Reply #8 – June 26, 2025, 08:26:27 am

Quote

Once you have the tank out you can get up in the belly of the beast and move, wiggle, or pry the hoses around to help make room that you don't have now, even a 1/2" is a bunch here. Once you start back you will need to build a wooden ramp/filler piece to be able to get the tank back in without getting the hoses hung up. I will hunt around and see if I ever posted a pic. of this part.

I did not plan to take the tank completely out but slide it far enough to change out the hoses. I was hoping to keep the bundle of hoses on top of the drivers side of the tank top.

Re: Fuel line replacement

Reply #9 – June 26, 2025, 01:18:32 pm

Here is what I did to keep every thing in place and not interfere with the tank. At the edges of the
aluminum it is important to bend the edges of the aluminum so it won't cut the hoses.

Re: Fuel line replacement

Reply #10 – June 26, 2025, 01:40:20 pm

Oh what a fun job. I was able to pull the tank out curbside using a cable bridal attached to the Mount point using a come along to pull it out. I used a .025 x 2" strap/spoon with a slight roll in it to hold the hoses and cables up on the top side of the tank to manipulated it to slide out. I absolutely would recommend pulling it all the way out so as you can clean inside and thoroughly seal the floor. The fiberglass panel on the driver side is just left in place and make sure you put it in before you reinstall the tank cause it's the first thing that has to go in the hole. I thought about deleting the fiberglass cosmetic covers Until I realize that they are used to prevent fuel from spilling back underneath the tank. You probably could do the same thing with a length of 600 mile an hour aluminum tape along the bottom. The spoon was absolutely required to reinstall a tank. And make sure you check flow through your lines all of them Before you finish. You can very easily kink them without realizing it. Also, while you have access to all the center cables, I would fill the voids with stainless steel wire wool to keep any rodents from coming in from the front axle area. Mine also had two vents right behind the front tires that picked up an awful lot of road debris, and I reduced the size of them substantially. I completely sealed the fiberglass panels to the walls and floor and around the filler neck with fuel tank sealant.

Re: Fuel line replacement

Reply #11 – June 27, 2025, 10:22:02 am

Thanks for all the good advice. I can see the merit of all. I was hoping not to pull the tank all the way out but with the strap or plate to hold up cables will eliminate the fears of not being able to keep other hoses and cables up when reinstalling the tank. Everything is ready to pull tank out including bridle hook up for tank. I am out of town until next week but will post progress photos when I get back. Grateful for ALL the tips. Very helpful and encouraging.
Daniel

Re: Fuel line replacement

Reply #12 – June 27, 2025, 07:15:08 pm

You said you removed 3 hold down bolts. All of the tanks that I have removed had 2 on each end making a total of 4 bolts.

Re: Fuel line replacement

Reply #13 – June 27, 2025, 09:01:38 pm

Interesting.. As you can see in one of the photos there are 3 on each end. Capacity 193 gallons!

Re: Fuel line replacement

Reply #14 – June 27, 2025, 10:47:26 pm

My tank has 3 bolts on each end and I used a pry bar and blocks of wood to pry the tank out.

Re: Fuel line replacement

Reply #15 – September 01, 2025, 08:28:21 pm

Time for an update from 2 months ago on fuel line replacement. Sorry for the delay but I was laid up with covid for a month then fell on my knees and was lame for another 3 weeks.. After trying to remove the fuel tank with a come-a-long and broke the harness that I attached to it, I decided to cut a hole in the floor. Carefully using a multitool to cut the 7/16 plywood floor and then using a knife to cut the 1 1/2" insulation left the thin fiberglass liner ceiling above the tank bay. I used a steel 6' rule between the hoses and the bay ceiling to protect the hoses as I cut through the fiberglass liner with a dremel from above. The 10" x 18" hole was perfectly aligned above the hoses and engine and generator supply fittings in the center of the 93 gallon fuel tank.

The extra hoses from the Aquahot and hydraulic lines for the slideout made it so tight that it prevented the tank from sliding out. We tackled the generator lines first pulling the old hoses out from the generator side by attaching new hose with barbed connector from the hole cut in floor. Much easier than I imagined but had to cut a hole in the generator cavity side wall to put return line in as the trident hoses are thicker than the old aeroquip and both would not fit through original hole.
2nd was the engine supply side pulled from hole in floor attaching new hose at the water fuel separator with barbed fitting. Fitting caught on the opening going into the utilities bay but was able to get it through by removing tunnel cover on bay in front of utility bay. I have not replaced the short section to the secondary fuel filter and lift pump yet. Next was the Aquahot. I relocate filter and supply lines to the bay on the aft side of the propane tank. Much less hose needed. The generator started after cranking for about 15 seconds. I drew the fuel to the water separator filter from tank with a small pump and engine started after about 5 seconds. The Aquahot lines had previously been reversed so after a lot of head scratching I figured it out and now it also works. BTW I used all the old push on fittings. The only thing left to do is repair the floor and carpet will be replaced. Many thanks to all those who contributed.

Re: Fuel line replacement

Reply #16 – September 02, 2025, 09:03:54 am

Nice job cutting that floor opening, definitely a measure twice item

From the pictures it looks like you will be able to get a solid patch in place.

Re: Fuel line replacement

Reply #17 – September 02, 2025, 10:01:20 am

How are you planning on replacing the floor?

Re: Fuel line replacement

Reply #18 – September 02, 2025, 10:32:24 am

The biggest problem with the floor repair is attaining rigidity with the patch and existing floor the last thing I want is a spongy spot in the floor. From bench testing different glues and foam sprays, what I have come up with is using aluminum sheet on the bottom inserted between existing fiberglass and the rigid foam with 1 1/2" rigid foam patch and 15/32" plywood on top laminated with Great Stuff construction foam. The Great Stuff is a closed cell polyurethane that adheres well to most surfaces. I am open to suggestions and if any of you have done this and found a solid solution please speak up. Also if you Know what does NOT work I would like to hear from you as well.

Re: Fuel line replacement

Reply #19 – September 02, 2025, 11:27:16 am

Cut all sides of the cut out and the patch piece at 45 degrees so that the patch is supported by the floor

Re: Fuel line replacement

Reply #20 – September 02, 2025, 12:04:15 pm

Great idea. I will do that.
Thank you.

Re: Fuel line replacement

Reply #21 – September 02, 2025, 01:01:15 pm

I was thinking taking angle iron and screw to side of existing floor, then you will have a shelf for insert to sit on

Re: Fuel line replacement

Reply #22 – September 02, 2025, 02:42:19 pm

I like the idea but you would have to remove some of the existing foam that is glued to the plywood. I guess you could fill back in with the Great Stuff foam and you would only have to do it on 2 sides.
Thanks

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