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Old 06-12-2013, 11:04 PM   #1
Lord Volvo
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Default 140 Fuel Tank Observations and Questions

I'm venturing into (for me) uncharted territory - working on my Yellow Brick's fuel tank. I figure it would be easier to work on the tank by removing it. Some observations and questions if I may, and feel free to comment on anything.

 photo DSCF5822.jpg
Pressure builds up in the tank, causing fuel to seep out of (I think) the bung drain. I plan to use POR-15 sealant around the edges of the bung flange and some Loctite 567 for the threads, which is supposed to be fuel resistant but removable should the need arise. Is there a better idea for the threads?

And why are there two drains at the bottom of the tank? Did it come like this from the factory?

 photo DSCF5832.jpg
Someone either punched a hole and plugged it with a screw, or simply screwed the tank for whatever reason. This may be another source of leaks since the undercoating has dissolved around the screw. About a 1/2 inch of the screw is sticking inside the tank. What's the best way of approaching this - loctite the screw's threads, or remove it and plug the hole with something (epoxy?)

 photo DSCF5829.jpg
There was some rust and dirt inside the tank which I removed with a vacuum. The tank's bottom has some rust but it's not as bad as I had feared. I also can't see any signs of sludge or other types of buildup. I had planned on using POR-15's fuel tank restoration system but now wonder if it isn't worth the trouble. What do you think?

The fuel pickup tube at the top of the image just above the opened drain had some kind of black plastic wrap around it that had degraded and flaked off. I'm wondering if it helped extend the hose to closer to the tank's bottom because there seems to be a few inches of clearance between the hose and the tank's bottom. Is this normal?

I also found what appears to have been a small gasket with a screen that (I assume) fit on the hose's end as a pre-filter. Most of the screen was gone and the remains of the fitting was lying on the tank's bottom. Will this lack of a pre-filter cause a fuel filtration problem downstream or should I just change the regular inline filter more often?

 photo DSCF5830.jpg
The tank's flange has some surface rust which I plan to treat with POR-15.

Finally, what is the best sealant to seal the tank's flange to the body when it's reinstalled? I don't want a permanent seal in case I need to remove it again.

As for the pressure buildup, I'm either going to hook up an expansion tank and route it to a charcoal canister and route that to the carbs, or vent it to the atmosphere as a last resort.

Any input or advice is welcome!
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Old 06-13-2013, 02:14 AM   #2
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So many questions.
1) Pressure should not build in the tank unless it's not vented properly, and if it does, it still shouldn't leak.
2) Loctite 567 is fine for the pipe threads.
3) There is a drain plug and access plug to the pickup filter in the bottom of the tank.
4) The hole with the screw in it needs professional repair. Most radiator shops repair fuel tanks. Have the tank cleaned and pressure tested to see where it's leaking from. If the seams are leaking, the tank is junk.
5) Did you get a mirror in the tank and look at the underside of the top of the tank. That's where you'll see most of the rust. The radiator shop will tell you if they think the tank is too rusty to use without coating the inside. I use a radiator shop that is authorized to do the RENU process. It's a little expensive, but it's guaranteed for life and they coat the inside and outside with different materials.http://www.gastankrenu.com/how.htm
6) The pickup tube should almost be sticking out of the plug hole. The filter goes over this tube. If you have the tank coated, ask the shop not to coat the end of the tube or the filter will be very difficult to install. If the pickup tube is broken or rusty, the radiator shop should repair it before coating the tank. You didn't say if your car was injected or not. A filter before the pump is mandatory for high pressure fuel pumps, but it doesn't have to be in the tank.
7) Your car should have had an expansion tank and charcoal canister. If they were removed and plugged, that could be the cause of pressure building in the tank. If you do vent the tank to atmosphere (which you shouldn't), use an inline fuel filter on the vent hose to prevent dirt from entering the tank with the makeup air.


Last edited by hiperfauto; 06-13-2013 at 04:36 AM..
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Old 06-13-2013, 09:30 AM   #3
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Thanks for the response. Some follow-up items if I may:

It has a Weber carb.

The expansion tank and charcoal canister were missing when I got the car two years ago. The previous owner had connected the tank's vent (#34 on the illustration) to the nipple on top of the filler tube, essentially created an unvented, closed system. Removing the gas cap would create a huge WHOOSH as pressure was equalized. I bought a canister and expansion tank from a 164 and plan to install it into the system (many thanks for the illustration - very helpful !) but I'm not sure how to route the canister's hoses to the Weber for both vacuum and vapor intake.

I told my situation to a guy who drives old BMW 2002s. He thinks that the expansion tank/charcoal canister setup would create too much vacuum in the gas tank and wouldn't allow the fuel pump to draw gas into the engine. I was skeptical of this theory since, as your illustration shows, Volvos were designed with this setup. He vents his 2002's gas tank to the atmosphere which I don't want to do.

I haven't looked inside the tank's top; I'll try to do so soon to see how bad the rust is.

I don't think the seams are leaking but I can't be sure of that.

Agree with a radiator shop as the best option, but I'm kinda broke these days and was seeing if I could do the job myself. I'll get some cost estimates; should be less expensive than buying a new tank from Europe. I think Skandix sells them but at a cost of >$500 plus shipping.

Thanks again; feel free to school me further!

Last edited by Lord Volvo; 06-13-2013 at 10:36 AM..
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Old 06-13-2013, 10:41 AM   #4
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Find a charcoal canister w/check valve, any will do but a '71 140 has it. The valve opens under vacuum at the carb base. Just put the recirc line to the tank the same as a '71 w carbs and it'll work fine.

If the tank is no good, which looks like a FI tank someone has made Swiss Cheese out of, can't be fixed, you at least can get a new 140 carb tank, AFIK the FI tanks are nla. If it's good and useable, sell it and get a carb tank.

I've done a POR-15 resto to a 140 FI tank and it was days of PITA work. Came out nice, though. I'd at least use their cleaner w/ nuts inside and slosh around until it comes clean.

The $150 for the aircraft tank resto is cheap when it compares to the time it takes to do a POR-15 treatment.
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Old 06-13-2013, 08:46 PM   #5
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Do not use a threadlocking liquid on the stock drain plug. Use Telfon tape or 'pipe dope" to seal the threads *if* needed.

It is there so you can remove it & drain the tank if needed. I'd keep that feature.

If tank is rusted badly inside, time for a new tank IMHO. (if one is available)
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Old 06-13-2013, 10:07 PM   #6
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Quote:
Originally Posted by smokeyfan1000 View Post
Do not use a threadlocking liquid on the stock drain plug. Use Telfon tape or 'pipe dope" to seal the threads *if* needed.
My understanding is that the Loctite 567 allows the plug to be removed if needed but is resistant to fuel. I don't think standard plumber's tape is. Someone correct me if I'm wrong.
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Old 06-14-2013, 12:06 AM   #7
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Quote:
Originally Posted by Lord Volvo View Post
My understanding is that the Loctite 567 allows the plug to be removed if needed but is resistant to fuel. I don't think standard plumber's tape is. Someone correct me if I'm wrong.
Plumbers tape is resistant to fuel. It's made of Teflon. But for fittings like this you want the thicker yellow stuff. That said, here's a good article on fuel port sealants:

http://www.jamestowndistributors.com...t.do?docId=563
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Old 06-14-2013, 12:11 AM   #8
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Quote:
Originally Posted by Lord Volvo View Post
My understanding is that the Loctite 567 allows the plug to be removed if needed but is resistant to fuel. I don't think standard plumber's tape is. Someone correct me if I'm wrong.
It looks to be a tapered pipe thread. Is it?

If so, no thread locker is *needed*

Teflon tape *plus* pipe dope is what is used on fuel oil delivery trucks to seal the NPT plumbing. I know, I used to plumb them.

Pro tip, be sure to apply the tape in same direction as threads thread into the bung.
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Old 06-14-2013, 12:25 AM   #9
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I have a nice tank from a 72 but I want $250 + shipping for it.
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how psi stock cna support?


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Old 06-14-2013, 09:03 AM   #10
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Quote:
Originally Posted by clipster View Post
Plumbers tape is resistant to fuel. It's made of Teflon. But for fittings like this you want the thicker yellow stuff. That said, here's a good article on fuel port sealants:

http://www.jamestowndistributors.com...t.do?docId=563
I don't want to make a federal case out of this but the article said:
Backyard mechanics will tell you they've used regular old gas resistant teflon tape (yellow stuff) with success. This is not recommended because it risks breaking free. Liquid or paste type thread sealants are kinder to sensitive components down stream. Mechanics repairing injectors, fuel pumps and carburetors can tell you first hand it is not uncommon to trace fault in the fuel component to clogging from a piece of teflon tape that washed off the ends of the threads, clogging in the first tiny micron orifice it encounters, if not the fuel pump then an injector or carburetor gallery. Either way it's a costly repair. Liquid or paste type sealant won't clog.

Maybe they are just trying to sell their product. I'm just trying to make sure that this tank doesn't leak once I reinstall it. Since it's out of the car, I want to do the best job I can.
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Old 06-14-2013, 10:36 AM   #11
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Quote:
Originally Posted by Lord Volvo View Post
I don't want to make a federal case out of this but the article said:
Backyard mechanics will tell you they've used regular old gas resistant teflon tape (yellow stuff) with success. This is not recommended because it risks breaking free. Liquid or paste type thread sealants are kinder to sensitive components down stream. Mechanics repairing injectors, fuel pumps and carburetors can tell you first hand it is not uncommon to trace fault in the fuel component to clogging from a piece of teflon tape that washed off the ends of the threads, clogging in the first tiny micron orifice it encounters, if not the fuel pump then an injector or carburetor gallery. Either way it's a costly repair. Liquid or paste type sealant won't clog.

Maybe they are just trying to sell their product. I'm just trying to make sure that this tank doesn't leak once I reinstall it. Since it's out of the car, I want to do the best job I can.
One does have to apply Teflon tape with good ol' "common sense".

Meaning use the tape only on the fitting where it seats in the bung's threads in applications such as yours.

Not on the end that is left exposed in the tank after tightening the fitting (leave it bare).

If you're worried about it, just use the pipe dope......

One app pipe dope and tape is definitely *NOT* recommended is on temp sensors threads.
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Old 05-01-2021, 06:34 PM   #12
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I know that I'm resurrecting an old thread here, but my situation is very similar to the original post.

Car is a 72 142s that hasn't been on the road since 1999, so obviously the gas tank is very suspect. I've removed it from the car and finally managed to remove the brass plug in the bottom of the tank. Had to destroy the plug to remove it as you will see from the picture.

When I look at the opening that this plug was covering, I see something inside the tank. Not sure exactly what this is and if it needs replacement.

So two questions please. What is the small mushroom looking thing inside the opening and where can I find a replacement brass plug. My tank part number is 12113061555. The ipd site shows this as a tank for an Amazon, not a 72 142s.







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Old 05-01-2021, 06:38 PM   #13
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Hopefully this image is a little better.
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Old 05-01-2021, 06:45 PM   #14
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That's a filter on the pickup tube. Yes, you should replace it after having the tank cleaned. The new filters are plastic where the old ones were brass.

VP has the filter and plug as do I.

https://vp-autoparts.com/en/artiklar...0_164_240.html

https://vp-autoparts.com/en/artiklar...s-140-164.html

FYI, it looks like VP now has repro fuel tanks for the 140 but they ain't cheap.

https://vp-autoparts.com/en/artiklar...series-73.html
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Old 05-01-2021, 07:05 PM   #15
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Thanks very much for the quick reply. Glad you could identify it from my picture.
I'll go out to the garage tomorrow and see if I can remove that filter. Is it likely that I can simply reach down and unscrew it, or was it a press fit?
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Old 05-01-2021, 07:43 PM   #16
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It's just pushed onto the tube but it'll probably fall apart as you're trying to remove it. The top and bottom of the filter are just held together by the screen which will disintegrate when you try to pull/twist the filter off.

The tube appears to be slightly bent so you'll need to align it with the access hole the get the filter off. If the top half of the filter stays on the tube you'll need some picks or bent pieces of stiff wire to pull it off.
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Old 05-01-2021, 11:01 PM   #17
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Here what the 2nd version of the intank fuel filter looked like. The original filters had a metal top and bottom.

The latest version of the these filters is now all plastic.

We might have a plug in stock, but please measure the outer diameter of the plug as there appear to be 2 different sizes. We do have the intank filter in stock.

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