My new year's resolution was to get Pongo running on the roads - and soon.
I've been sidetracked by projects as well as leaving town three times for family matters and had let Pongo suffer on the lift.
I knew the tank was still leaking, evidenced by the smell of fuel in the garage.
Closer examination and the leak seemed to be from the tank mount.
I'd clean and dry it and the next day, it would be wet and fuel forming to drip off the lowest part of the tank.
Last week or so, I filled up the bath tub and dunked the tank.
This revealed an air bubble or two from the tank mount, but my welder said that I needed to apply air pressure to the tank and watch for air bubbles.
Today (Jan 1), I plugged off the fuel supply with hose and a piece of aluminum rod.
Then I wrapped up a rag around a blow tip and stuffed that in the filler hole.
This yielded a lot of blowby.
Somehow, I got the idea of machining an aluminum plug to fit in the tank opening.
In the center, I used a letter B drill bit, which was allegedly .001" larger than one of my air tip's wands.
I turned down a piece of scrap and tried wrapping tape or rubber chuncks around it, but it was just wrong.
So I next thought to try an o-ring.
With a groove machined into the plug, I got one that was a perfect fit.
The next hurdle was getting the dang plug to stay in the tank with air pressure.
I sat there looking at the fuel filler cap and realized I just needed a cover plate and I could use the three screws that the filler cap uses.
Another piece of scrap laying around would become a useful part.
I clamped a filler cap to this plate and used a transfer punch to locate the screw holes.
A sharpie marker delineated the opening of the cap, which when cut out, would allow access to the central hole in the plug for the blow tip.
I awkwardly set the 4" round cover plate in the vice in the mill using some cheap softjaws resting in the vice's fixed jaws.
I first used the 5mm counterboring tool on the three punch marks.
Of course, I wasn't paying attention when clamping the tool and had to reposition it so I could bore to full depth on one of the holes (was too close to the vice).
At least I set the quill stop on the counterbore, so they'll be the same depths.
Next up, I drilled a hole near the center of the filler.
I followed it up by machining a rectangular hole near the center of the filler.
Last, I flipped the plate to machine off a raised portion in the scrap part from the previous project.
Click on the two parts to see my "tank leak tool box".
After the tank mount is brazed around the perimeter, we'll test it with this setup.
The tank plug and holding plate could probably be used to try and blow out the dent, but I'm a little worried about pressure harming the plastic fuel sending nut.
If anyone wants to rent the plug and cover plate for leak testing or attempted dent blowing, let me know.
The last issue was to critique the fuel shut off.
I previously thought it wasn't working, but now it appears to be functioning OK.
Perhaps being dry for so long caused it some issues.
This is very common in fuel systems; let them sit around dry then they'll misbehave for a while when first reintroduced to fuel.
We'll see if this suspect part allows fuel to seep out of the carbs once the tank is fixed.
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