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Old 04-06-2014, 02:19 PM
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Dr. Marneaus Dr. Marneaus is offline
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What do I need to do to this rear gas tank? or should I go bronco?

Okay.

Because of my offset axle/centered transfer case situation, I'm now tossing around the idea of just running a stock centered rear end, AMC20 or D44, from an 80-91 wagoneer.

It'll bolt right up, I'll have to swap ring and pinion to match my front, or swap my front to match the rear, and will get rid of ANY compound angle. However, this will require me to ditch my coffin tank and go with a later style, or go with a rear mount.

When I bought my jeep a previous previous previous owner had installed an auxiliary gas tank. My previous owner had removed the coffin because they thought it was rusted and clogging the carb (turned out to just be vapor lock, derp). So when I bought it it was just running the rear tank. I eventually pulled out the rear tank and went back to the original tank for simplicity. (it's hanging down low in this pic, thats not where it mounts)


Looks like it sat for a while with "some" gas in it.



The Aux tank had no provisions for a vapor recovery system, and when i pulled it i found it was nasty inside. solid as a rock but rusty. Outside dimensions put it at 22 gallons. So, lets say 21 or 20 based on filler location, etc. I figure thats okay, its about the same as stock so i wont be LOSING anything.

Pro's over a bronco swap: I already have the tank, I know how to mount it (re-drill 3 holes I welded up), and it wont require any fab work to the jeep, also it lines up with the stock fuel filler location perfectly. Also, it's a pretty dang beefy material, and it hangs no lower than the hitch so shouldn't hurt departure angle at all really and its not super low in general.



What needs to be done to it to make it function properly? I know i will need to clean/line it. I plan to convert it to a generic universal type fuel sending unit. 5 bolts vs. the 6 bolt on it now. Gasket will cover the old holes.

1. I dont have a fuel return line currently, should I install a bung so if (when?) I go EFI it'll already be plumbed?

2. Vapor recovery/venting. My current coffin tank has 2 lines that go to the check valve in the rear render well. Then these two lines go up to a vapor canister on the firewall, and then into the snorkel on the air cleaner. Is this necessary? Should I install 2 bungs for this and run it as stock?

If one was to consider a bronco or other swap, what needs to be done or modified on that, to make it mount and to make it flow/breath right?
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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44

Last edited by Dr. Marneaus : 04-06-2014 at 02:27 PM.
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Old 04-06-2014, 03:00 PM
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will you install the nu sender in the ole senders hole?

since you have all the parts, and you believe its 20gals.

install this and run it, then you can save $$$ for a 33g Bronco
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Old 04-06-2014, 04:28 PM
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Quote:
Originally Posted by Kenall
will you install the nu sender in the ole senders hole?

since you have all the parts, and you believe its 20gals.

install this and run it, then you can save $$$ for a 33g Bronco

Yes, new universal style sender would go in the same hole, so the gasket would cover the holes, or since this has been sitting empty for years, I could fill it with water and weld up the old holes. Either way, easy peasy.

But back to the question at hand, does this need vapor recovery tube fittings and whatnot?

Also, i hear the 33gal bronco tanks hang LOOOOOWWWWWWWW, even if you have a 3" body lift?
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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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Old 04-06-2014, 04:47 PM
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Quote:
Originally Posted by Dr. Marneaus
Yes, new universal style sender would go in the same hole, so the gasket would cover the holes, or since this has been sitting empty for years, I could fill it with water and weld up the old holes. Either way, easy peasy.

But back to the question at hand, does this need vapor recovery tube fittings and whatnot?

Also, i hear the 33gal bronco tanks hang LOOOOOWWWWWWWW, even if you have a 3" body lift?

if you don't need the vapor canister for smog id say no on the recovery line.

but I would plumb in a fuel return for EFI.
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Old 04-07-2014, 11:37 AM
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Will a POR15 gas tank kit do the trick here?
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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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  #6  
Old 04-07-2014, 01:10 PM
joe joe is offline
 
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Quote:
Originally Posted by Dr. Marneaus
Will a POR15 gas tank kit do the trick here?
Just my two cents. What are you expecting the goop to do for you? If the metal is getting porous it might help for awhile, but if you expect it to cover/seal your existing crud or rust...don't do it. If the tank needs to be cleaned it needs to be cleaned. No magic pour-in cures for a dirty tank. I'm not big on tank sealers but if you use one the tank has to be CLEAN for the goop to stick. If you think rust/crud coming loose from the tank is a hassle, you ain't lived till you get the tank sealer sloughing off and plugging up your fuel system. Tank sealers stick fairly well to clean metal. Sticking to rust/crud/E10 deposits...not so much. If'n were me I'd get that tank as clean as possible (bare steel is good/perfect) and then just use it, sans any sealer goop. That plate steel box tank is easy enough to cut apart and clean thoroughly and have it welded back together. In Vegas I don't suspect moisture forming new rust would be an issue. Clean steel has worked well for fuel tanks for decades especially in the desert SW.
Tank sealers...a bah humbug temporary fix even in a clean tank but when the 'temporary' period expires and you've got to start over cleaning the tank...you'll really wish that residual sealer goop wasn't ever in there.
Clean it, bolt it up, run it.
On a side note since you're in limbo about differential, driveshaft fuel tank shape/location compatibility don't rule out a custom plate alum(or steel) tank made to your specs. If the shop has the material in stock or you can wait till his next scheduled metal order/delivery prices are decent. If he has to special order and have the material shipped separately...you eat that added cost.
Cutting/welding plate isn't rocket science. They're not building a support rib holding an airplane wing in place. Years ago I had a local shop build me two 250 gal fuel tanks from alum for my 40 ft commercial fish boat. Going by the "at the time" material/labor prices it was pretty good compared to the cost of fixing my existing steel tanks.
Research all your options and put sealer goop on the bottom of the list.
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Old 04-07-2014, 01:22 PM
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don't know if you saw this thread but this is how I did mine, gives you an idea of how it hangs.

http://www.ifsja.org/forums/vb/showthread.php?t=168517
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  #8  
Old 04-07-2014, 02:17 PM
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Dr. Marneaus Dr. Marneaus is offline
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Quote:
Originally Posted by joe
Just my two cents. What are you expecting the goop to do for you? If the metal is getting porous it might help for awhile, but if you expect it to cover/seal your existing crud or rust...don't do it. If the tank needs to be cleaned it needs to be cleaned. No magic pour-in cures for a dirty tank. I'm not big on tank sealers but if you use one the tank has to be CLEAN for the goop to stick. If you think rust/crud coming loose from the tank is a hassle, you ain't lived till you get the tank sealer sloughing off and plugging up your fuel system. Tank sealers stick fairly well to clean metal. Sticking to rust/crud/E10 deposits...not so much. If'n were me I'd get that tank as clean as possible (bare steel is good/perfect) and then just use it, sans any sealer goop. That plate steel box tank is easy enough to cut apart and clean thoroughly and have it welded back together. In Vegas I don't suspect moisture forming new rust would be an issue. Clean steel has worked well for fuel tanks for decades especially in the desert SW.
Tank sealers...a bah humbug temporary fix even in a clean tank but when the 'temporary' period expires and you've got to start over cleaning the tank...you'll really wish that residual sealer goop wasn't ever in there.
Clean it, bolt it up, run it.
On a side note since you're in limbo about differential, driveshaft fuel tank shape/location compatibility don't rule out a custom plate alum(or steel) tank made to your specs. If the shop has the material in stock or you can wait till his next scheduled metal order/delivery prices are decent. If he has to special order and have the material shipped separately...you eat that added cost.
Cutting/welding plate isn't rocket science. They're not building a support rib holding an airplane wing in place. Years ago I had a local shop build me two 250 gal fuel tanks from alum for my 40 ft commercial fish boat. Going by the "at the time" material/labor prices it was pretty good compared to the cost of fixing my existing steel tanks.
Research all your options and put sealer goop on the bottom of the list.

The aforementioned kit comes with everything for chemically cleaning it, not just pouring in a sealer. The metal is 100% solid, it's just got that dusty surface rust in there.
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Dr. Marneaus is now officially my idol.

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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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  #9  
Old 04-07-2014, 02:25 PM
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I used the Bill Hirsch tank sealant on my CJ-6 tank. http://www.hirschauto.com/prodinfo.asp?number=GTS The Hirsch product claims that it's alcohol resistant. As mentioned, cleaning is essential.

There are quite a few horror stories out there about the POR-15 tank kit. It'd probably be ok, but the most popular products seem to be Bill Hirsch or Red Coat. Read this pamphlet http://www.hirschauto.com/sealer.pdf - I believe POR-15 products are all MCU, so it's probably referring to them.
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Old 04-07-2014, 02:45 PM
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So, can i just fill this thing with vinegar to clean it out and then not coat it?
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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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  #11  
Old 04-07-2014, 03:50 PM
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Quote:
Originally Posted by Dr. Marneaus
So, can i just fill this thing with vinegar to clean it out and then not coat it?

I would coat it. If it's rusty now, it will only not rust more if you keep the tank filled with gas. These tanks are supposed to be plated internally. When the plating goes they rust. No alternative to coating or replacing at that stage, IMO.

The process I followed was a box of 1" drywall screws and power washer detergent and shake shake shake. Rinse and drain, dry now? Drying after cleaning should be easy there. Run some air from your compressor or the vacuum into the tank to speed drying. Then the Hirsch tank etch, and the sealant. Allow to dry for a couple days. Took a summer weekend to complete.
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Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk
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Old 04-07-2014, 03:55 PM
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Dr. Marneaus Dr. Marneaus is offline
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Quote:
Originally Posted by tgreese
I would coat it. If it's rusty now, it will only not rust more if you keep the tank filled with gas. These tanks are supposed to be plated internally. When the plating goes they rust. No alternative to coating or replacing at that stage, IMO.

The process I followed was a box of 1" drywall screws and power washer detergent and shake shake shake. Rinse and drain, dry now? Drying after cleaning should be easy there. Run some air from your compressor or the vacuum into the tank to speed drying. Then the Hirsch tank etch, and the sealant. Allow to dry for a couple days. Took a summer weekend to complete.

gotcha. so you were simply saying to use a better product, but still just clean it best as I can (i had read the drywall screws and vinegar as well), then do some sort of coating.

Thats a heavy arse tank, gonna be a work out shaking it! haha. Too bad i dont have a tractor or something to strap it to the tire of.
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Dr. Marneaus is now officially my idol.

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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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  #13  
Old 04-07-2014, 04:06 PM
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It's not Red Coat instead http://damonq.com/red-kote.html "Red-Kote"

The motorcycle guys seem to really like this sealant, while the car guys go for Hirsch.
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Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk

Last edited by tgreese : 04-08-2014 at 06:23 AM.
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Old 04-08-2014, 06:23 AM
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Vinegar? Where did you hear about vinegar? I would wash with detergent first, then de-rust or etch as needed.

AFAIK acetic acid (vinegar) does not have any effect on rust. I know that oxalic acid will dissolve rust. Oxalic acid is available commercially as wood bleach, and was the primary ingredient of old-fashioned radiator flush. Muriatic acid (hydrochloric acid) will also dissolve rust, but it will etch the steel and releases hydrogen gas when it reacts with iron.
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Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk
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Old 04-08-2014, 10:30 AM
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Dr. Marneaus Dr. Marneaus is offline
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Quote:
Originally Posted by tgreese
Vinegar? Where did you hear about vinegar? I would wash with detergent first, then de-rust or etch as needed.

AFAIK acetic acid (vinegar) does not have any effect on rust. I know that oxalic acid will dissolve rust. Oxalic acid is available commercially as wood bleach, and was the primary ingredient of old-fashioned radiator flush. Muriatic acid (hydrochloric acid) will also dissolve rust, but it will etch the steel and releases hydrogen gas when it reacts with iron.

I read it on the interweb so it must be true.

I dunno seems a prett popular item to use to clean it out
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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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Old 04-08-2014, 02:45 PM
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Are you sure you need to swap out your tank ? Jeep ran the same tank with the D-20 T-case (much more centered) rear axle.

I am running a NP241 (centered t-case) on a 77 WT (not as much offset) rear, my 79 Cherokee runs a D-20 T-case (centered) with a not quite centered but closer rear axle. both run stock tanks.
I am not sure but I would guess a 80+ tank would also fit in the hole without much other than finding the parts. (skid plate, tank) , might be a good time to swap a later fill neck in and loose the goofy vent setup that the 79- ones had. MTS might also have an option.
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Old 04-08-2014, 03:03 PM
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Quote:
Originally Posted by mdill
Are you sure you need to swap out your tank ? Jeep ran the same tank with the D-20 T-case (much more centered) rear axle.

I am running a NP241 (centered t-case) on a 77 WT (not as much offset) rear, my 79 Cherokee runs a D-20 T-case (centered) with a not quite centered but closer rear axle. both run stock tanks.
I am not sure but I would guess a 80+ tank would also fit in the hole without much other than finding the parts. (skid plate, tank) , might be a good time to swap a later fill neck in and loose the goofy vent setup that the 79- ones had. MTS might also have an option.

A mostly centered axle will fit, a centered axle will not. It will hit the tank.

Probably alot easier for me to install this tank than source and fiddle with adapting to a post 79 tank. Maybe if i found one down the road i would consider it as an option to install and have 2 tanks, but I'm not particularly concerned with it at this point.


Another question since I'll be working on this tank I have. The pickup is in the center as seen in the pics.

Should i keep it that way, or should i plug that hole and install a bung on the front face of the tank right down near the bottom edge? I guess that wouldnt work too well if I was going up hill with a low tank huh? Probably better pick-up-ability located there in the center.
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Originally Posted by FSJunkie
Dr. Marneaus is now officially my idol.

The Mag - The Wag

The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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Old 04-08-2014, 03:28 PM
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OK, Was not sure if a true centered axle would work, I assume a 74-79 Wagoneer/NT-Cherokee with D-20, rear axle is not to be found in your area ?
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Old 04-08-2014, 04:08 PM
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That would be the unicorn. I have not had luck locating one anywhere close enough for it to be worth the effort to get it, and freight also sorta puts it out of the reasonable price range as well.
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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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