What's the procedure on "sprucing" up one's gas tank? After removing it, how does one get the 30 year old dirt out and to prevent rust from forming in the future? Also, how does one test for leaks? I'd like to isolate the source of that gas smell in the trunk. I plan to replace the filler tube as well.
-GE
Radiator shops can acid etch the interior and coat it to prevent rust in the future, but the labor cost equals the cost of a replacement tank.. or thereabouts. Your choice on that one.. I did it on a new tank, just cause I'm weird and like the term "permanent" ;) I thought I was chasing a rust problem, but it turned-out to be my mechanical pump that varied all over creation making the jetting uneven. The guy at the radiator shop thought I was nutts, but took my money anyways and did the job.
I have two '73 Supers and both have the same gas smell problem. From the front looking in to the bonnet, the tube with the tight bend on the left side that enters the top of the filler on both my bugs leak vapors. Normal heater hose can't do that bend and I'm thinking of trying a couple
90 degree adapters with new hose to solve it for myself. It's the last hose left that hasn't been replaced on my good Super, so it's gotta be that one.Before you go ripping your tank out, I'd suggest you look into a venting issue and/or reserve issues and/or fuel line issues. Venting can be an issue every once in awhile when dealing with termperature changes. Obvious signs of leakage is a puddle or dampness around the tank or loss of volume without driving. I believe that POR (among others) sells a sealing kit that will take car of any future rust. - DB
Gotta be?
The most common cause of this problem is the little rubber bands that go around the "nipples" on the tank and the filler tube. These bands are necessary to get a good seal on the large diameter hose that goes there. If the tank has been out, then those bands were probably forgotten and those connections will leak.
Your radiator repair guy was right. Most people who get the polymer coating in their tanks are sorry within 3 years. A well sealed tank won't rust inside. If it's rusty, then there must be a way that water is getting into it. Fix the water leak and the rust problem will go away.
------------------------------------------------ Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA
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Yup. Come over sometime and sniff the hose. Yes, the rubber bands are there and filler to tank hose is new too. I even fixed the crack in the long plastic expansion chamber. It's the last part left, really. I never said it was the OP's problem, but definitely is mine and worth checking on his bug, too.
Why's that? You didn't explain.
Like the filler cap not sealing and taking in water. Maybe 30 years of cheapo water gas one fills up with... But as the OP says, his tank is already rusted.
The Bentley manual says to derust a tank use either a phosphate derusting agent (Rodine50 or similar) or with hydrochloric acid mixed in.
The coating usually plugs up any small openings. Most of these tanks have a number of small hose fittings that need to be there for vents, etc. Those often get blocked.
Then after a few years, the coating starts to peel off....
------------------------------------------------ Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA
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