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Twin carb - Balance tube

Discussion in 'Fuel System & Electrics' started by stooedwardes, Aug 11, 2020.

  1. stooedwardes

    stooedwardes New Member

    Messages:
    19
    Location:
    Yackandandah, Vic Australia
    First up, my bus (1977 2lt) has always run nicely. A long time ago I noticed the outlets for the Balance Tube (between the carby manifolds) had been blocked off. I asked a mechanic who told me that they run better that way. Is this true?
    I can't imagine that the tube performs a major function but should I just hook it up with some fuel line anyway?
     
  2. stooedwardes

    stooedwardes New Member

    Messages:
    19
    Location:
    Yackandandah, Vic Australia
    This is the connection that I am referring to (green X's indicate where mine have been blocked off)

    D3597A2F-84FB-4690-9EA9-DFEAD9E8623C.jpeg
     
    Last edited by a moderator: Aug 11, 2020
  3. rstucke

    rstucke Well-Known Member

    Messages:
    1,432
    Location:
    Wamberal NSW AUS
    that's the pipe for the vacuum brake booster
     
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  4. rstucke

    rstucke Well-Known Member

    Messages:
    1,432
    Location:
    Wamberal NSW AUS
    I'm guessing you've got a brake booster on your front beam. How are the brakes?
     
  5. stooedwardes

    stooedwardes New Member

    Messages:
    19
    Location:
    Yackandandah, Vic Australia
    Hmmmm... They seem fine but I guess I don't know any different!

    So that outlet nearest to the right carby runs a vacuum (?) tube to the booster which is up the front of the cab (underneath)?
     
  6. rstucke

    rstucke Well-Known Member

    Messages:
    1,432
    Location:
    Wamberal NSW AUS
    The pipe goes through the fire wall on the passenger side (you can see the bit that goes through the firewall on the right of your picture). There is a non return valve on the other side, from there it runs up to the booster on the front beam
    The pipe should be behind the carbies
     
  7. stooedwardes

    stooedwardes New Member

    Messages:
    19
    Location:
    Yackandandah, Vic Australia
    Thanks Rstucke. I will probably be amazed how good the brakes feel after hooking it up!!
     
  8. Alpal

    Alpal Moderator Staff Member

    Messages:
    8,783
    Location:
    Melbourne Bend of Islands
    Just make sure there are no vac leaks.
    And maybe review your mechanic?
     
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  9. rstucke

    rstucke Well-Known Member

    Messages:
    1,432
    Location:
    Wamberal NSW AUS
    It may have been plugged of cause the booster is cactus
     
  10. grumble

    grumble Well-Known Member

    Messages:
    1,207
    Location:
    Taree
    Or the elbows were buggered and the "mechanic" couldn't work out how to get new ones. :rolleyes::rolleyes:
     
  11. stooedwardes

    stooedwardes New Member

    Messages:
    19
    Location:
    Yackandandah, Vic Australia
    Yeah, I reckon someone took the easy way out a long time ago.

    I have been trying to find a replacement "balance tube" but to no avail. I reckon I can just hook it all upon with vacuum hose and a T piece surely?
     
  12. rstucke

    rstucke Well-Known Member

    Messages:
    1,432
    Location:
    Wamberal NSW AUS
  13. Kai

    Kai Well-Known Member

    Messages:
    4,772
    Location:
    Sydney, NSW
    im pretty sure ill have a spare one, it might be an auto one actually and have an extra port for the vacuum modulator. ill have a look on the weekend.
     
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  14. stooedwardes

    stooedwardes New Member

    Messages:
    19
    Location:
    Yackandandah, Vic Australia
    Thanks Kal. Much appreciated!
     
  15. stooedwardes

    stooedwardes New Member

    Messages:
    19
    Location:
    Yackandandah, Vic Australia
    Hey Kal. Don’t bother. I have one...it was there all the time!! I was going from memory (as I was away fromHome for work). It is the central offline system cut of solenoid that has been blocked off and from what I can tell this is a common occurrence.

    I will be replacing the rubber elbows and tube though as they are perished.

    Sorry to have wasted everyone’s time but I learnt alot (like that I have servo assisted brakes and where they get their vacuum from).
     
  16. Alpal

    Alpal Moderator Staff Member

    Messages:
    8,783
    Location:
    Melbourne Bend of Islands
    That makes sense. Otherwise brakes would have been pretty poor!
     
  17. cbus

    cbus Well-Known Member

    Messages:
    12,843
    Location:
    sunshine coast
    All good familiarisation
    ;)
     

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