Fuel leak......Montgomery Texas

Scott & Heather · January 26, 2017, 03:20:15 PM

I'm going to post a quick pic/video thread here to show you how simple really it is to RR the tank give me a few minutes. I JB welded mine and I had several leaks some of which were fairly large. I have been driving the coach for a couple of years now and put on about almost 20,000 miles without a drop of diesel leaking from the repairs.

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Scott & Heather · January 26, 2017, 03:58:03 PM

Ok, so to pull your tank you should just have to undo the two bolts that strap the top of the tank. If you are facing the side of the tank (filler cap) you should see those bolts one behind the other on the left top of the tank. They may be rusty. You have to loosen/remove those to get the tank out. Once you do that, disconnect the fuel lines, and disconnect the fuel gauge sending unit wires. Then what we did was to put a tow strap around the top vent and gently pull the tank out using a bobcat. A car or truck or come-along would work too.

We pumped the fuel in the tank into a 275 gallon tote. These things are all over Craigslist for $50. Buy a cheap transfer pump that's made for fuel and be patient. It takes forever to empty a full tank.

Once the tank is out, wash the outside thoroughly. You can use detergent on the inside too but you have to be really sure you rinse it well or you'll contaminate your fuel later. Once the tank is pressure washed, I used a wire wheel on an angle grinder to deep clean the surfaces that looked the most corroded.

Now, here's the fun part: get a shop vac put the hose in the "blower/exhaust) port of the vacuum and insert the other end of the hose into the filler cap. Use duct tape to form a seal around the hose and fill hole. You might also have to tape the vent tube too so that air doesn't escape. You should hear the tank "pop" a little as it expands from the positive pressure.

Once I did that I used some soapy detergent water in a spray bottle to find the leaks. They don't always blow nice big bubbles. Most of my leaks (even the good sized ones) just generated a trickle of small bubbles I could barely notice. But enough of those, and you are dumping $$$ on the ground. Spray every area that you might even think is leaking. Go slowly trying to find every leak. When you find one, mark it with a sharpie or liquid marker. Once you're done finding all of the leaks and have marked them, you'll need to rinse and dry your tank. In the hot Texas sun in the summer this only took a few hours for me. But you definitely want the tank dry as can be on the outside and inside.

Now that the tank was dry, I removed the hose from the blower/exhaust port on the shop vac and inserted in on the vacuum/suction port. I left the other end inserted into the filler opening on the tank duct taped to form a seal. I turned on the vacuum and this again made the tank "pop" as it contracted from the negative pressure created in the tank. While the vacuum was running and creating this negative pressure inside the tank, I mixed some two part JB weld together according to package instructions. I then puttied the liquid weld into and onto the leak areas. The idea is to get the liquid weld to flow into or "suck" into the holes slightly to help seal the leaks better. I puttied more and more layers of JB weld until I had really covered the leaks with a nice substantial layer of weld. I turned off the shop vacuum and let the JB weld set for a couple of days in the hot sun. I then filled the tank with water to test for leaks. NOT A DROP. then I drained the tank of water and let it dry/air out for a day. Once it was dry, I pushed it back into the bus on a fresh sheet of wood and reconnected the lines and wires and bolted the strap back down. I pumped my diesel back into the bus tank and it hasn't leaked a drop since 2 years and 20,000 miles later. And I've traveled in 110°F weather to -9°F weather. I've been as high as 9000 feet altitude and everything in between in just one day. So if it were going to let loose, it would have by now. I'll eventually need to repair or replace the tank but I'll wait until the JB weld lets go. Good luck:

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Scott & Heather · January 26, 2017, 03:59:33 PM

Here's a video of how my bubbles looked:
https://vimeo.com/201213930

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ccbmster · January 26, 2017, 04:42:54 PM

Nice run down and pics Scott! Appreciate it, but I pulled the trigger on having a place do it for me. I bought some 8D's from them recently and they treated me ok on those, so I went back to them and they quoted me $250 to $350 depending on if they ran into problems and how much the welder will charge to do the welding....they said he is really reasonable. So probably less than $400 (hopefully a lot less) all said and done.

Took them about an hour or a little more to drain all the fuel and pull the tank out. The leak was right where I thought it was and REALLY small. Probably could JB Weld or something like that and go forever, but my main man mechanic in SoCal agreed with those in here that advised welding it, so I guess I will just go with that.

If anyone has to have something done here in the Montgomery-Conroe TX area, Rite Way Heavy Truck Services seems to be a pretty decent place.

Scott & Heather · January 26, 2017, 05:51:56 PM

I will leave you with one thought to ponder. Almost every single one of my leaks were at weld joints from previous weld attempts. You can clearly see the weld plates in my photos. Just another data point.

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eagle19952 · January 26, 2017, 07:57:08 PM

Quote from: Scott & Heather on January 26, 2017, 05:51:56 PM
I will leave you with one thought to ponder. Almost every single one of my leaks were at weld joints from previous weld attempts. You can clearly see the weld plates in my photos. Just another data point.

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do yourself a favor, after they weld it...slather JB Weld on it

whats a few more bucks after $400.00

Gary Hatt - Publisher BCM · January 27, 2017, 07:32:51 AM

I have heard about a liquid or something you can pour inside your tank, before filling it with fuel and maybe roll your tank around or something to help put a coating on the inside too. Someone on the Forum should be able to tell us what that is. For maybe a few more bucks, it is even more added insurance.

eagle19952 · January 27, 2017, 08:43:01 AM

Quote from: Gary Hatt - Publisher BCM on January 27, 2017, 07:32:51 AM
I have heard about a liquid or something you can pour inside your tank, before filling it with fuel and maybe roll your tank around or something to help put a coating on the inside too. Someone on the Forum should be able to tell us what that is. For maybe a few more bucks, it is even more added insurance.

they sell that stuff for motorcycle tanks...not the sharpest pencil in the box idea.

they suggest you put a cup of aquarium gravel and roll it around to prep the tank...

Scott & Heather · January 27, 2017, 09:11:30 AM

Once that stuff goes bad and starts to flake your tank is done. I'd keep the fixes external and weld or seal externally. Those MCI tanks aren't cheap

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eagle19952 · January 27, 2017, 05:23:42 PM

Quote from: Scott & Heather on January 27, 2017, 09:11:30 AM
Once that stuff goes bad and starts to flake your tank is done. I'd keep the fixes external and weld or seal externally. Those MCI tanks aren't cheap

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that too...
flaking ...especially if it is not prepped well...anm MC tank. maybe...130 gallon tank..no way.

luvrbus · January 27, 2017, 05:49:13 PM

Quote from: Scott & Heather on January 26, 2017, 05:51:56 PM
I will leave you with one thought to ponder. Almost every single one of my leaks were at weld joints from previous weld attempts. You can clearly see the weld plates in my photos. Just another data point.

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I don't doubt your seams leaked Scott that is one terrible looking job for a tig weld

,did someone use a mig with wire ?

chessie4905 · January 27, 2017, 06:22:37 PM

They used to solder tanks where they leaked. Maybe that is a lost art now.

ccbmster · January 28, 2017, 12:00:35 PM

All done.

Excellent weld job by Sal Visoso of Fabtex Metal Workers. He only charged $105.00 and the whole job ended up being $398.00 Total.

bigred · January 28, 2017, 01:09:47 PM

The newer bus are all coming with plastic tanks anyway ,so if it came to replacing the tank guess that is what I would do !!!

Seangie · January 28, 2017, 05:20:55 PM

Quote from: ccbmster on January 25, 2017, 05:48:18 PM
My MCI 102A3 suddenly started a slow drip of diesel fuel from the frame right below the fill door. Probably a cup or so of fuel in 24 hours. I can't see where in the heck it is coming from. Top and sides of the tank seem to be dry.

Any ideas, or tips on who would be a good person/shop to have check it out in this area would be very much appreciated.

Thanks in advance.

Inside my fill door is a drain hole with a rubber tube that runs to the ground. If I overfill the tank then fuel will drip from the cap as it sloshes around as we are driving. Then it drains out that hole. It could easily be a half to full cup that drains out from spillage if I overfill.

-Sean