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"Balance Pipe" hoses

Discussion in '"Stock" Alpine' started by Scotty, Sep 16, 2020.

  1. Scotty

    Scotty Donation Time

    Long story short, seems I have a really minor, kind of nagging gas leak, located on the 'filling' tank side at the first hose, the side closest to the tank. It wets a small section of the pipe but the 'wing' floor is dry. I'm assuming the two metal clamp-ish assemblies that holds this onto the pipe are called Jubilee Clips, if not, please correct me.

    I had the tanks and crossover pipe totally stripped down, boiled and coated awhile ago and the car hasn't been driven much. There are no other leaks from any section and my fuel filter is see-through clear.

    I've read advice about being careful when tightening these, so the question goes how much should I tighten and are there any telltale signs that I should heed and change the hose?

    Edit: This is on an early SIV.
  2. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    I assume you installed new rubber joint hoses when you re-did the tanks and crossover pipe.

    The double wire clamps (a.k.a Jubilee clamps) are not very good at providing a seal. I re-did my tanks and pipes a couple of years ago and re-used the original double wire clamps. I got tired of the gas smell in the trunk. I had tightened the clamps, but the smell persisted. A gas leak detector confirmed leaks at the rubber hose connections, so I swapped the clamps out. I replaced them with Breeze 9428 liner clamps - all stainless steel (size 28 ā€“ 2-1/4"). I replaced the clamps without needing to move the rubber hoses. I siphoned the gas out. Then removed the double wire clamp screw and bent the clamps open enough to remove them. A little bit of gas might leak out at this point, so put a cloth under the connection to catch any gas. Then I fully opened the liner clamps to allow them to be slipped over the rubber hose. Then reconnect the band into the worm screw and tighten them up.

  3. Bill Blue

    Bill Blue Platinum Level Sponsor

    I used both styles. I had no problems as long as the clamp was not positioned "sideways" on the hose. That can be a problem with large hose and working in cramped space with poor visibility. The gear clamp seems have some ability to straighten itself on the hose as it is tightened, the wire clamp does not.

  4. Mike O'D

    Mike O'D Gold Level Sponsor

    I'm glad you posted that Mike. I have a slight gas smell in my trunk, but can find no leaks anywhere. I did re-use the wire clamps, so I'll look to replace them and see if that takes care of it.

  5. Rick Young

    Rick Young Platinum Level Sponsor

    When I reinstalled mine after coating the tank my hose dripped. I double clamped them using the worm drive hose clamps. I tightened them with a Plumber's T handle No Hub torque wrench.
    which is pre set to 60" lbs. They are on the Plumbing aisle of big box stores.

  6. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    I also ended up replacing the double wire clamps on the rubber filler neck. (Clamp size 36 ā€“ 2-3/4") However, I think I still have a slight gas smell at the filler neck and might try replacing that rubber piece.

  7. Tim R

    Tim R Silver Level Sponsor

    A common cause of fumes is from the breather pipe that goes across the top inside the rear scuttle from one tank to the other. It is amazing how often people screw tonneau pegs into this pipe after having the car re=sprayed or when fitting a tonneau or new soft top. No petrol leaks out but when you go round a corner fumes get pushed out of any pin holes by the change in pressure as the petrol is moved by G force.
    Tim R
    RootesRooter likes this.
  8. Mike O'D

    Mike O'D Gold Level Sponsor

    Actually after thinking about it, my S3 has heavy duty looking worm drive hose clamps. The band isn't punch with holes, but rather has indentations stamped into them. I'm pretty sure I haven't drilled into the area after installing the new breather hose. I'll have to check around a little more to see if I can find anything.
  9. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    What kind of gas leak detector did you use? I have a natural gas detector for use in the house, but don't think it works with gasoline.
  10. hartmandm

    hartmandm Moderator Platinum Level Sponsor


    It is a Klein Tools ET120. Iā€™d loan it to you if you want.

  11. Gordon Holsinger

    Gordon Holsinger Diamond Level Sponsor

    Replace the vent hose ethanol eats rubber. Auto parts store should have ethanol resistant hose
  12. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    Thanks, Mike. I may take you up on that at a later date.
  13. hartmandm

    hartmandm Moderator Platinum Level Sponsor

    That was done when I redid the tanks.

  14. Barry

    Barry Platinum Level Sponsor

    The truth is that ethanol only attacks rubber hose that is not rated for ethanol. "Carburetor hose" (marked SAE J30-R7) was developed before "gasahol" existed and is not required to be resistant to ethanol. Rubber fuel hose that is marked SAE J30-R9 (aka "EFI hose") is completely resistant to ethanol and has low permeation. AFAIK, there is no rubber tubing (looks like hose, but has no reinforcement) that is rated for ethanol.
    Last edited: Sep 19, 2020

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