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Topic: 1/16' vacuum lines?

in Forum: C3 Cooling and Heating Systems


1/16' vacuum lines?

Posted: 3/21/16 8:29pm Message 1 of 4
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Former Member
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Joined: 9/11/2015
Posts: 8
Vette(s): 1981 C3, 4 speed, Maroon
The small line going to the hot water shutoff valve has broken right at the firewall grommet. Can anyone tell me what size these lines are? 1/16"?


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Re: 1/16' vacuum lines?

Posted: 3/22/16 3:20am Message 2 of 4
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WEST SENECA, NY - USA
Joined: 12/3/2001
Posts: 2379
Vette(s): 1981 Blue Ice Met. w/pearl ghost flames TKO500 5speed. LS1 Swap 3.45 Dana 44.
I believe they are 1/16" I.D.
Later today I'll go out to the garage and take a look at mine. 

Last fall I bit the bullet and bought a vacuum hose kit from Dr. Rebuild. It is a pain in the arse of a job to do.I also tested each vacuum diaphragm in the HVAC system to rule out any other leaks.

The replacement hoses are a lot beefier in comparison to the spindly factory ones. 




GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.
3.54 Dana 44
'69 "N11" Sidepipes
Borgeson Steering Box
Born 8/1981
Sequence #3975




Click here to see more pics of my Vette on CarDomain.


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Re: 1/16' vacuum lines?

Posted: 7/18/16 1:15pm Message 3 of 4
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Former Member
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Milwaukie, OR - USA
Joined: 10/19/2015
Posts: 71
Vette(s): '78 Silver Anniversary T Top coupe,58k orig miles. THM350 auto, 350 L48, JBM headers,Oyster White interior,.as of Nov '15 in process of painting.
IF you can get to the end of the vac line next to the firewall..buy a simple in line connection that fits the original line  and some new vac hose and reconnect the line to the heater hose in line solenoid..  IF Stuff was working right and that line had >8 Hhg vacuum before..that should do it..
IF things in your hvac/A/C were not functioning properly and Compressor  charge are up to snuff..Let me know..I can direct you to how to simply fix the problem..
BTW, IF you want to replace the entire hose that passes thru bulkhead..IT goes to the bypass solenoid switch which is accessed by removing the glove box interior.It's controlled by the temp cable that runs from the HVAC controls in the console..jim



Re: 1/16' vacuum lines?

Posted: 7/18/16 1:19pm Message 4 of 4
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Former Member
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Milwaukie, OR - USA
Joined: 10/19/2015
Posts: 71
Vette(s): '78 Silver Anniversary T Top coupe,58k orig miles. THM350 auto, 350 L48, JBM headers,Oyster White interior,.as of Nov '15 in process of painting.
Sarge81 said: I believe they are 1/16" I.D.
Later today I'll go out to the garage and take a look at mine. 

Last fall I bit the bullet and bought a vacuum hose kit from Dr. Rebuild. It is a pain in the arse of a job to do.I also tested each vacuum diaphragm in the HVAC system to rule out any other leaks.

The replacement hoses are a lot beefier in comparison to the spindly factory ones. 



Sarge..Doc Rebuild has some good info but his rep hoses don't pass thru the cowl-bulkhead ports because they are larger OD.
Without conversing about what issues you had with your hvac system..I'D bet it was the temp control cable adjustment for the water shut off bypass that was the real problem..:)Jim



in Forum: C3 Cooling and Heating Systems


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