Gas Tank

Discussion in 'Small Block Tech' started by SCamaroSS2000, Nov 3, 2016.

  1. SCamaroSS2000

    SCamaroSS2000 Well-Known Member

    This might not be the best forum to ask. I just pulled my gas tank. It actually looked super clean inside, I was very surprised actually. The sending unit looked good as well except for the portion that is exposed to the elements. I do have a gas leak somewhere though and can't figure it out. The rubber hose is old for sure but I do not see any holds or cracks. I do notice the venting hoses on the tank and thought making gas was coming from there. The only other thing I can think of is that gas is leaking from the tank itself. With how nice the tank looked inside, I can't imagine that it would be leaking though. Maybe the steel gas line? It appears to be intact though. Opinions? Also, can I plug up my vent lines and just run a vented gas cap? I don't see any issue with it but thought I would ask. Last thing is the sending unit was grounded to the top of my rear end. There was a retaining looking piece that was holding the brake lines in place. The groudn was attached to a nut that kept the retaining piece locked to the rear end.

    I tried to attach a few pictures but they wouldn't load.
     
  2. CJay

    CJay Supercar owner Staff Member

    Normally, if its been leaking for any length of time, dirt get attracted to the wetness and the dirty area should point you in the direction. Sometimes the O ring dries up that seals the sender. Ive seen rubber hose become porous. They look fine until fuel gets in them and then they look like one of those soaker hoses you use in the garden. The ground wire for the sender is screwed to the trunk pan with a sheetmetal screw.


    I wouldn't of taken anything apart until I pinpointed the where the leak was coming from
     
  3. SCamaroSS2000

    SCamaroSS2000 Well-Known Member

    I sent the sending unit out to get refurbished. I am going to clean out the tank even though it looks pretty good to me and then seal it. From there, I will use new hose. I have a feeling the gas was leaking from the vent lines. Are they supposed to be attached to something and the outlets should point upwards? I think they were just dangling around. I noticed it leaking when the tank was full so that is why I assume it was the vent hoses.
     
  4. CJay

    CJay Supercar owner Staff Member

    The vent hoses are supposed to point straight up. There is a bracket that holds them. We are talking about a 69-72 correct?
     
  5. SCamaroSS2000

    SCamaroSS2000 Well-Known Member

    Where is the bracket, I do not see one? Its a 70.

    Well, that most likely explains the leak. especially when the tank was full. Never noticed it when it was half full or less. Also, where do I attach the ground, just right above the sending unit? I do not see a hole, I wonder why it was attached to the rear pumpkin? It looked stock I will say but it was different than how I heard they were grounded.
     
  6. flynbuick

    flynbuick Guest

    The bracket is built into the vertical body surface in front of the tank. Reinstall a surge tube if it is missing.
     
  7. sean Buick 76

    sean Buick 76 Buick Nut

    I would not bother with a fuel tank sealer just confirm it does not leak while you clean it. I hang the tank from the rafters of the garage, add a bottle of trans fluid, bottle of carb cleaner and a package of bs from your sons you gun. Shake the mixture around, leave it for a few hours, and then shake it around again and then leave it overnight to see if it leaks at all... Maybe tip it to one side or the other to ensure it doesn't leak on the sides.
     
  8. SCamaroSS2000

    SCamaroSS2000 Well-Known Member

    I highly doubt the tank leaks. No joke, the interior was pretty much spotless, I couldn't believe it. Even the sock on the sender looked great, no crud at all. I am debating doing anything to it besides replacing all the rubber hoses. I am like 90% positive that is what I will do.
     
  9. SCamaroSS2000

    SCamaroSS2000 Well-Known Member

    Hey, what size screws attach to the rear of the straps near the bumper? Size and length? I have misplaced mine and I am putting the tank back in.
     
  10. CJay

    CJay Supercar owner Staff Member

    They are special screws. But you can probably get away with a #14 sheet metal screw. Offhand, I think they are about 1 1/4"
     
  11. SCamaroSS2000

    SCamaroSS2000 Well-Known Member

    Also, I never found a bracket for the vent tube. I think I am going to have to use a zip tie unless someone has a picture of what it looks like and where it attaches.
     
  12. CJay

    CJay Supercar owner Staff Member

  13. hugger

    hugger Well-Known Member

    Don't remove the 3/8 bolts in the straps, there is no need you have to bend the piss out of them to get them back in with tank in place, and there is no "bracket" that holds the tube it just is held in place by a flat 3/4in wide metal strip that is bent slightly and screws into the body
     
  14. SCamaroSS2000

    SCamaroSS2000 Well-Known Member

    I cannot find the bolts. I have the long bolts for the front but I cannot find anything for the rear. So are the screw or 3/8 inch bolts. If they are bolts, what are the length, like an inch and a quarter?
     
  15. hugger

    hugger Well-Known Member

    They are 3/8 head 1/4in coarse thread special screws, there is no threads down towards the head of the bolt, any coarse thread bolt will work tho, 1 to 1.25 long yes. And to be clear I was saying don't remove the straps unless you are changing them which I wouldn't nobody make any worth using IMO , the are too long and not bent correctly, but if you are put them in b4 the tank
     
  16. CJay

    CJay Supercar owner Staff Member

    The closest match is a #14 sheetmetal screw
     
  17. SCamaroSS2000

    SCamaroSS2000 Well-Known Member

    Well, I put everything together. Sending unit worked, new vent hose, new fuel hose but I still have a leak, two actually. There looks to be a leak where the gas tank seam is in the front. I don't see any gas near the sending unit or the vent hose or on the top half of the tank for that matter. It appears to be where the two half of the tank come together where the seam is. Is this a common thing? At this point, I am thinking to get a new tank. So Spectra? What model for a 1970 GS? I have read somewhere to get a 69 model which has a shorter filler neck for a 70 GS?
     
  18. alec296

    alec296 i need another buick

    Interior of tank means little. The seams rust . You won't see that. I sealed my tank. Your gonna need to run car on lift and check leaks. Hoses get porous as mentioned. May not look bad until pressure is put on them.
     
  19. SCamaroSS2000

    SCamaroSS2000 Well-Known Member

    Thanks. All my hoses are new and I could visually see the leak. The top half of the tank was drive so we're the hoses. Is it worth sealing or just buying a new one for a few judged bucks. Do the new one have any improvments, if so what is the spectra part number? I read to get a 69 model due to having a shorter neck?
     
  20. alec296

    alec296 i need another buick

    The cheaper ones you will need a neck soldered in.
     

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