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Ossojones

37 Pontiac 6 fuel tank leak

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I'm working on bringing my families 37 Pontiac 6 back on the road.  Things were going well until we noticed that the fuel tank has gotten very thin in spots and there is even a tear near the rear of the tank.  I haven't been able to find a local shop who is willing to weld or solder it up.  We did get a poor patch job but it's already leaked through.  Does anyone know if the 37 Chevy tanks will fit the 37 Pontiac 4 door?  The 37 Chevy seems to be a really common new item on the market but I've found nothing for the Pontiac.  Also, not having luck finding an original for sale either.  Any help appreciated.  I don't want this car to sit and rot.  My parents met in this car in the mid 60's and I'd love to take them cruising in it again.

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If you join the Pontiac Oakland Club  ( all pontiac ) . If you are not a member there website might be limited to you. Monthly you get a mag. that has classifieds and a list of speclist by year that could help you. 

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Greetings from a 36 Ponitac owner!

 

The place to ask about gas tank repair is a radiator shop, of the sort that actually takes radiators apart and rebuilds them. These are getting hard to find, but if you have one locally, it is a better bet than a welder.

 

Lots of parts are available on http://www.pontiacparts.net/  and you might also ask them who has gas tanks.

 

The Early Times Chapter is a club for flathead Pontiacs, they are here: http://www.earlytimeschapter.org/

 

 

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We found a radiator shop who is willing to check it out.  Dropping it off today.  Thanks for the info on those sites, I've been scrounging around daily looking for a replacement but still no luck.  For others reference, the 37 Chevy tank has a different filler neck location as far as I can tell so it's not a valid replacement without some metal work.

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My GM projects, 35-36yrs (Chevy, Pontiac, Buick)all have the same gas tank with different filler neck locations..

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We ended up using the radiator shop and they were able to clean up and solder it.  It should hold for a while until I can find a better solution.  I did talk to the welder there and he said they do filler neck relocation.  I just need to find a tank that fits the pontiac which should be fairly easy.  There is a lot more filler necks for sale than there is tanks so I don't even need to cut the original.  I can just store it away and have a newish one built.  Thanks for the help on this.  Next if finding a pinion seal that actually holds.

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Make sure you have the proper weight gear lube and that your rear end is not overfull.  Contrary to many manuals the lube does NOT need to be up to the filler level.  If you can insert your little finger bent downwards and can feel the gear lube you have enough.  Also make sure you vent is clean.   Often it is not the seal's fault when it leaks.

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Since I have worked with pre-war Pontiac and Buick gas tanks, gas lines, gas pumps and tank mounted sending units I would encourage you to make sure that sending unit is clean and the dash gauge reads correctly while you have access to it.  I have found that getting your existing unit rebuilt rather than replacing it is the way to go for I have tried but not found a reliable replacement.  Also you might consider blowing out the fuel line that goes from the tank to the engine mounted fuel pump and cleaning out the sediment bowl on the pump. Your fuel tank problem is not uncommon and can take patience and some money to get the issue resolved.  I speak from experience with these old cars!!!

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The sending unit is 0-30 ohms and can be checked with an ohmmeter. It should get as close to zero in the tank is it does on the outside. If it reads higher in the tank, the float is probably hitting bottom (it shouldn't). Flip the tank upside down, and it should come up at least 30 ohms. If it fails either test, but is ok outside the tank, the arm is bent.

 

If the floats are cork, the old ones may not be reliable. We have a thread going about that elsewhere on the forum. California Pontiac may have them, if not, the Buick ones on Bob's Automobilia are the same as Pontiac.

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The rear is just blasting out the seals we used.  They were a visual and measurement match but not the actual part number so the rear just doesn't like them.  I'm hoping it's just the seal and not an imbalance or something else wrong with the shaft or the rearend.  You don't feel anything even at 55 though.  Sending unit seems OK.  We had it out and cleaned it when we pulled the car out of storage late last year prepping for the first start.  It seems to read correctly and wasn't in bad shape, although it may deteriorate quickly now with regular use.  I'll have to check the ohms on it, thanks for the specs.  The pump is new/rebuilt so it's clean as well.  Carb has been sent off and cleaned up because it had some issues we couldn't resolve with a rebuild kit.  I've only had a few good miles so far this year.  I'm hoping to get over the hump and kill all these gremlins soon.  This is by far the oldest car I've worked on.  I've dealt with cars back to 48 so I'm aware of the constant struggle.  This one just seems to be harder to get parts for so I'll be scrounging EBay and the swap meets for a while.  

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If the sending unit works, great. I think we were just trying to save you from pulling the tank another time. I need to pull mine one more time....

 

Regarding the pinion seal, if it is the right size it really should work, unless it is made of the wrong material for gear oil or something. If you are getting these from a bearing store or something make sure you tell them it is for gear oil.

 

I don't have a pinion seal (1936 with torque tube) so have not dealt with that. If you have a vent, make sure it is open. If you don't have a vent, and you are using modern seals out at the axles too, you are going to have to add one.

 

If there is a groove where that seal is running, look into a "speedi-sleeve" to get rid of the groove. If there is no sealer on the outside of the seal where it drives into the bore, put a little indian head on it and drive it in.

 

And as Tinindian said, don't fill it all the way to the plug.

 

 

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On 5/9/2018 at 12:49 PM, deac said:

have you tried Kurt Kelsey for that seal??

No, who's that?  Bought the last one from pontiacparts out of California but it hasn't come in yet.

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Kurt Kelsey has NOS Pontiac Parts.  His user name on these AACA forums is Kornkurt - Kurt Kelsey 641-648-9086.  He's a funny guy!!!

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Gee Chris, thanks for the compliment.  My long gone uncle would have asked "Funny strange or funny Ha ?"  I have a NOS genuine GM pinion seal $35 $ $8 postage. 641-648-9086

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On 5/13/2018 at 6:59 PM, Kornkurt said:

Gee Chris, thanks for the compliment.  My long gone uncle would have asked "Funny strange or funny Ha ?"  I have a NOS genuine GM pinion seal $35 $ $8 postage. 641-648-9086

Thanks Kurt, the one from Pontiacparts did the job so I'm good.  I'll keep you in mind as we go through this thing though.

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