Gas tank/emission hard line replacement [message #360069] |
Wed, 11 November 2020 11:46  |
Tilerpep
 Messages: 404 Registered: June 2013 Location: Raleigh, NC
Karma: 7
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I replaced the hard line section that runs along the back of the transmission, against the cockpit step, that runs from the gas tank vent rubber line on driver side to the short rubber line that connects to the carbon canister on the frame under the passenger seat. I used a 51 inch nicopp preflared 5/16 brake line tube hoping to use the flare to help hold the clamp on, but the flares made the connection too big so I cut two inches off both ends and just radiator clamped the rubber tubing back on. This replaced an original looking 46 inch steel tube that I discovered clogged shut with rust for the second time in five years. I had the front wheels off and liners out and the job was much easier. There were three support connections shared with the passenger front brake line. Two on frame, and one that connected brake to vent line behind transmission. This line is essential for proper tank venting (filling, temp changes, using the gas). You can check for flow in this line by removing top hose from check valve in driver rear wheel well or at hard line under driver seat, and the connection at the charcoal canister, gently apply air and have a helper listen for flow. Just putting it out there as a reminder to check, as well as possible parts solution.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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Re: Gas tank/emission hard line replacement [message #360071 is a reply to message #360069] |
Wed, 11 November 2020 17:59  |
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Matt Colie
 Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
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Senior Member |
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Tilerpep wrote on Wed, 11 November 2020 12:46I replaced the hard line section that runs along the back of the transmission, against the cockpit step, that runs from the gas tank vent rubber line on driver side to the short rubber line that connects to the carbon canister on the frame under the passenger seat. I used a 51 inch nicopp preflared 5/16 brake line tube hoping to use the flare to help hold the clamp on, but the flares made the connection too big so I cut two inches off both ends and just radiator clamped the rubber tubing back on. This replaced an original looking 46 inch steel tube that I discovered clogged shut with rust for the second time in five years. I had the front wheels off and liners out and the job was much easier. There were three support connections shared with the passenger front brake line. Two on frame, and one that connected brake to vent line behind transmission. This line is essential for proper tank venting (filling, temp changes, using the gas). You can check for flow in this line by removing top hose from check valve in driver rear wheel well or at hard line under driver seat, and the connection at the charcoal canister, gently apply air and have a helper listen for flow. Just putting it out there as a reminder to check, as well as possible parts solution.
Tyler,
It is absolutely unessential for fueling and use fuel. Those are both duties of the Fill Vent line that goes fron the level senders to the fill neck. The correct number fill cap is also a check valve to allow air into the system. This is not to say that you should ignore the plugged line, but it is not essential for operation in the short term.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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