Fuel Tank Issues

[doublez]

I just took off the "refurbished" tank that the PO gave me only to find that it is still rusty and there are a few holes (3, maybe 1/8") that aren't sealed very well.

 

For money reasons I want to keep this tank so how can I get the old sealer out?

 

To plug the holes I was thinking of some sort of epoxy that will withstand fuel. Is this ok?

 

Also would it be necessary to re-seal the tank or can I just get rid of all the rust with electrolysis?

[hoov100]

Take the tank to a radiator shop and have them boil and clean it out, then get some tank repair epoxy (looks like JB weld) once that is fixed, POR 15 makes a gas tank sealant to seal and line the inside of the tank to prevent it from happening again.

[doublez]

I found some epoxy to seal the holes. I'll call around to get it boiled out today.

 

[edit] seems like no one in the metro can boil a tank for me. I did find one engine machine shop that might be able to do it, but I would have to go in tomorrow.

Is there any acid I can by to do it my self?

 

What about sealing (semi-permanently) the vent holes? I would like to get rid of the vapor canister because the rubber lines are all cracked and deteriorating.

Can I use aluminum caps or would it be better to use brass or steel or something? Can I epoxy them on or should I weld/braze them on?

 

thanks

Edited July 15, 2010 by doublez

[New-to-240z]

There was a thread you cna search for by me a month or two ago. I had a TON of responses in it and there are links there that will give you all the information you need to remove the evap tank. I have yet to drive my car with the tank removed, but it was simple enough.

 

(you'll need to goto classiczcars . com to find that thread. Silly me, I thought I was still in that forum HAHA. I have the same screen name over there as well.)

Edited July 16, 2010 by New-to-240z

[doublez]

I was looking for that guys tank process thread before but I couldn't find it.

Thanks for pointing me to it.

[doublez]

Boiling it didn't get everything out, so now what?

I'm thinking about cutting a panel off the bottom and pulling the rest out since all of the sealer is now loose, but in big pieces.

Is this a good idea or bad?

 

(I don't have much cash so I'm not interested in tank re-nu or something like that)

Edited July 20, 2010 by doublez

[letitsnow]

I cut 2 holes in my tank on the top, sandblasted the inside, and cut the old lines out. I replaced the lines with 3/8" 304 stainless hard lines and soldered them back in, I also flanged the holes I cut and soldered patches in. Right now I'm coating the inside with the por15 kit, I'm actually doing the etching step right this minute.

 

Going this way was a MAJOR PITA, soldering SS to mild steel is a pain because of the different specific heats, SS absorbs and rejects heat much slower than mild, meaning that getting them both the right temp is difficult, especially when using a torch like I was. Also, getting the patches to sit right and not leak was a bit of a pain, but not as bad as the lines. I cut the holes on the top because if they did start to leak there would be a lesser chance of spilling a large amount of fuel right near the exhaust. The tank sealing process is quite time consuming and boring as well. BUT, all of what I did was pretty cheap, I bought the por15 kit for ~$75, the SS lines for ~$20, and the soldering supplies that I used probably totaled ~$30, but I had a lot of those already. I've got a TON of time in this thing so far, probably 30hrs at least.

 

Most old sealers can be removed by putting a gallon of M.E.K. in and letting it soak for a few days on different sides. You can get M.E.K. at lowes I think. The por15 directions said 'stripper' and some other directions say MEK.

[doublez]

At least I'm not the only one who would do that much for a tank then

 

I cut 2 square holes in the top and I pulled as much of the sealer out as I could. There is still a little bit in some cracks to scrape out yet. There is some residue/varnish type stuff left behind though. Will the marine clean remove that or should I get something else like MEK or HCl?

 

For your holes did you make new patches or reuse the cut out? I cut 3 sides of a rectangle and peeled the metal back for access inside. I was hoping I would be able to fill in the gap when welding but it looks like it might be to much. I used 1/32" abrasive discs.

 

Just curious, why did you flange your holes? Why solder?

[letitsnow]

I flanged the holes so that my patches would sit nicely before I soldered them, it's difficult to bridge gaps with solder too. I soldered them because it's pretty difficult to get a completely leak free weld I also couldn't weld the SS lines to the tank. It's relatively easy to get a leak free seal with solder. After doing it once, I would recommend tack welding the patches in before laying the solder down, keeping them in place and tight to the tank was a bit of a pain. For the patches, I made new ones out of some scrap sheet metal, I think it used to be a volkswagen door.

 

The marine clean should get rid of any fuel varnish, but I don't know about any sealer residue.

[doublez]

How did you make your flange? I would think it would need to go into the tank so it doesn't interfere with the car when mounting the tank.

This is what I was thinking...

or am I way off?

 

In case I decide to solder, what kind did you use and what flux? I've never soldered steel, but I think you need silver in the solder?

Are the breather exits soldered on?

 

Thanks for all your help

Edited July 22, 2010 by doublez

[letitsnow]

I used a flanging tool that I borrowed from a friend, it was basically a set of modified vise grips. The patch doesn't have to be perfectly flat because the tank is mounted on rubber isolators, not a whole lot of precision is needed. This is how I did mine. Just make sure that the gaps you're soldering are very tight, it makes it much easier.

 

I used a normal pipe flux for the steel, but I had to use a special SS flux on the lines. I mostly used 60/40 rosin core solder for the steel, I used a solid core for the lines because the rosin core didn't agree with the SS too much. I'm not sure if what I used was the best stuff, but it seemed to work fairly well, although some parts were a bit more difficult to tin than others.

 

I'm pretty sure that all the lines and vents are spot welded and then brazed or soldered on.

[letitsnow]

Just put gas in the tank for the first time.......NO leaks!!! It seems to supply all the fuel I need and the car feels strong.

[doublez]

awesome. I ordered my por kit the other day so hopefully I can do the same soon.

[letitsnow]

Yeah, I hope it works out well for you.

 

The por stuff is WAY easier to do than the eastwood kit I used last time and it was definitely worth the $25 more.

[doublez]

Just did the last step today, now just to let it dry for a few days! My opinion of this product so far is that its great. Cleaning the tank is easy, etching it is easy and then the sealer it self appears to be a very good compound. I'm excited to see how it is dry.