Community Forums

Inthe70s · 07-26-2015, 09:20 AM

Hi, I have a '97 Rexhall Arebus, F53 chassis with a 75 gallon metal fuel tank. It has a very slow leak in one of the welded seam areas. I've patched it on a temporary basis until I decide how to resolve this problem. I don't want to patch it on a permanent basis so I figured my options are:
1. Drop the tank, have it cleaned and have the seams re-welded by a professional. While it's down do the usual preventative maintenance like a new fuel pump, new hoses, etc.
2. Replace the tank with a new plastic tank. There is a shop in Denver that makes heavy duty plastic tanks for all sorts of commercial applications. They can make a custom tank based on the design of my existing metal tank. I think with the plastic tank there won't be any seams to worry about. I don't know the cost at this point but I am assuming it's reasonable.

I am interested in opinions about these options. I can't think of another viable option. Has anyone replaced their tank with a plastic tank? Thank you for your assistance.

Hit_the_Rhod · 07-26-2015, 09:43 AM

Option # 2 definitely! If I had an 18 year old metal fuel tank who's welded seams have started failing, I would not repair it. If one weld has failed, all the others are suspect in my opinion. Having a professional welder re-weld all the seams on that old a tank would probably be costly, and may open up another can of worms. The inside of the tank may have corrosion damage from water entrainment, condensation, etc, and I think you would be better off getting a replacement tank, either metal or plastic brand new than attempting to repair that age of tank! Been professionally welding since 1979, starting with inconel, monel, and stainless steel aircraft exhaust systems. Just my opinion for what it's worth.

FIRE UP · 07-26-2015, 11:29 AM

Quote:

Originally Posted by Inthe70s

Hi, I have a '97 Rexhall Arebus, F53 chassis with a 75 gallon metal fuel tank. It has a very slow leak in one of the welded seam areas. I've patched it on a temporary basis until I decide how to resolve this problem. I don't want to patch it on a permanent basis so I figured my options are:
1. Drop the tank, have it cleaned and have the seams re-welded by a professional. While it's down do the usual preventative maintenance like a new fuel pump, new hoses, etc.
2. Replace the tank with a new plastic tank. There is a shop in Denver that makes heavy duty plastic tanks for all sorts of commercial applications. They can make a custom tank based on the design of my existing metal tank. I think with the plastic tank there won't be any seams to worry about. I don't know the cost at this point but I am assuming it's reasonable.

I am interested in opinions about these options. I can't think of another viable option. Has anyone replaced their tank with a plastic tank? Thank you for your assistance.

"I think the plastic tank won't have any plastic seams to worry about". Well Sir, that may or, may not be quite true. Now, unless they've told you how they make their tanks, many plastic tanks and, lots of other plastic items are "Plastic welded" together. For years, the RV industry used Poly ethylene plastic welded holding tanks, fresh water tanks and other tanks etc. It was the norm back then. Plastic welding is still in use today.

But, mostly the RV industry has turned to "cast" or, "molded" Polypropylene tanks. If you don't know what that is, it's a simple two-piece case that, is slightly filled with Polypropylene pellets and then it's heated and spun, at a very slow rpm. Those pellets begin to melt. As they melt, they stick together in a very thin sheet, that is formed to mimic the inside of the tank molds.

In this fashion, the tank is basically ONE PIECE with no seams. All inlets and outlets, vents etc. are what's called "Spin welded" to the surface of the tank. They basically cut a hole in the tank and, a machine, like a big drill motor, places a plastic fitting with a flange built into it, up against the hole and, begins to spin at a rapid rate. The two surfaces get so hot, they literally weld and seal themselves together.

Basically, that's how the modern holding and fresh water tanks, and I'm assuming, some fuel tanks are made today. But, the art of plastic welding is still alive and well. As for repairing or, re-welding your old tank, that's an "iffy" process. Some serious precautions must be taken and, it's a timely process. And, as has been stated, it may lead to conditions that are worse than what you're starting with. Good luck.
Scott

R2Home · 07-26-2015, 12:35 PM

My question would be what type of supports are in place for the steel tank? Will the poly tank be able to support the weight of 75 gallons of fuel? If the current tank placement is such that there is a platform for the tank to sit on then poly may be the way to go. As for welding the old tank, what does the inside look like? If it is more or less clean then I 'might' be tempted to repair it. If the tank is a 'real pain' to get out, then I would be replacing it. What about getting a replacement steel tank? Is that an option?

ga traveler · 07-26-2015, 12:46 PM

If you can find a metal fabrication shop, your best bet is a stainless steel tank. (if you plan on keeping the motorhome) No more rust worries. I would also think about adding another twenty five gallons to the capacity, if you take long trips, as we do.

glarnold · 07-26-2015, 12:48 PM

Many decades ago, I was advised by an older than dirt auto mechanic, that a "temporary" repair on a small fuel tank leak could be easily formed by rubbing a bar of Ivory soap across the leak, effectively sealing it. Then, according to him, the soap and gasoline form a new bond that will probably never fail.

I did try this on a couple of small leaks, and it did appear to work.

JMHO.

wa8yxm · 07-26-2015, 05:02 PM

How about both.. yes both.

There is a product.. You can do it yourself but I recommend having a pro do it. This is basically a pour in "Plastic Rubber" it lines the tank, is gasoline and/or diesel proof, rust proof, (They also fix any weak spots on the tank first) takes a few days to do the job but works very well.

SOME Radaitor shops can do it. I've done it on two cars and never had a problem post seal. One was DIY one Pro.. Both worked well.

Less cost than the new tank,, better than a solder/weld job.

pop-sicle · 07-26-2015, 05:37 PM

I am not sure I would want a plastic tank but maybe after I see spec on it.

My choices would be in no specific order

1. Replacement from Ford
2. Have fabricated out of aluminum stainless better but way more expensive.
3. Check out the surplus marine market could get usable aluminum tank that might need some modification for pump and lines. .but could cause gas Guage to read incorrect. Just a matter of adjusting to how Guage reads.

djbmsu · 07-26-2015, 06:38 PM

More than likely you can order a replacement tank from Ford for less than you can clean and repair an 18 yr old tank. You won't own the RV long enough to justify the cost in a stainless tank.

Inthe70s · 07-26-2015, 06:58 PM

Wow! Thanks for all of your great responses, advice, and opinions! I'm glad I posted this question because I certainly learned a lot. The shop that can make the custom plastic tank works with both polyethylene and polypropylene and they have been in business for 30 years. That's a good point about the support of the current tank. I'll need to take a closer look at the existing set up. For some reason, I never thought of contacting Ford to see if they still make a replacement and if so, what the cost would be. The RV is 18 years old and while we have no intentions of selling it in the near future (we absolutely love it) we also don't want to spend a ton of money on this tank issue either. We only put about 600 miles per year on it since we use it primarily as a "cabin or condo" at the lake during the summer. Most of those miles are just getting it up to our lake spot in the spring and then bringing it back home for the winter. Some might say just patch it, due to the minimal movement, but I like things fixed right and permanently. Thanks again and please keep the suggestions coming!

FleetMan · 07-26-2015, 08:03 PM

Another option to consider, contact Transfer Flow out in California. They make custom tanks for the aftermarket and are NHTSA certified.

Ray,IN · 07-26-2015, 08:57 PM

Check out Por-15 fuel tank sealer before spending a wad of money. Somewhat like a liner for a fuel tank.

jsides · 07-27-2015, 07:01 AM

Stay away from welded plastic tanks. You cheapest way to go is to take your tank to a good rad shop. They will boil it out clean it up and reseal the seams. People in the car restoration business do that when a direct replacement tank is not available.