vacum hose kit?
Thread Starter
Racer
Joined: Oct 2010
Posts: 395
Likes: 0
From: winterville NC
vacum hose kit?
Ok guys I just bought a 79 vette last week and I knew that the AC did not work... so after I have started to check her out I have decided to change out the vacum hoses on the AC. I have seen in vette books that you can buy replacement kits that are color coded....my question is I seen kits for heater and ones for AC, are those for heaters for vettes without AC or am I mistaken? If I a mistaken could someone point me into the right direction here.....lol
just wondering if this might could be the correct kit.......hope links are allowed ............ http://www.ecklerscorvette.com/corve...1977-1982.html
just wondering if this might could be the correct kit.......hope links are allowed ............ http://www.ecklerscorvette.com/corve...1977-1982.html
Last edited by McVette; Aug 25, 2011 at 09:44 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Why would you replace all the hoses before you know that any of them are bad? The hoses are the least likely item to fail (except where exposed to UV rays and the outside environment). They can be disconnected, plugged up, or missing...but they are rarely defective. Learn how to properly diagnose the vacuum system before you start making 'wholesale' changes that may, or may not, yield any improvement.
Instructor
Joined: Jul 2011
Posts: 142
Likes: 1
From: Fort White Florida
I was in the same situation and was thinking of changing all the AC Vac hoses. I did the smoke test and found out it was a problem with the AC Vacuum Control Valve. I replaced that and now the AC works properly. My engine is not stock and so the vacuum is lower to begin with so I also smoke checked all the vacuum circuits and found other places where I was losing vacuum. Make sure you check all sources of possible vacuum leaks before just changing out hoses. It will save you some frustration.
Thread Starter
Racer
Joined: Oct 2010
Posts: 395
Likes: 0
From: winterville NC
oh my bad i should have stated in earlier post but several are missing and most of the others look to be dry rotten and i realize this prob not be only problem but I figured it would be a good starting point????
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
The A/C Vent Heater system has only 2 plastic tubes (hoses) that are normally damaged- because of under hood heat.
I wrote this up awhile back for this problem & many have used it to fix the system.
On at least later C3 the problem is that heater is the default position (no vac. or vac. leak) due to being designed in the north. Vent should be default. Very safe bet the problem is 1 OR 2:
1) The vac. line from engine may be damaged from heat - a small plastic tube that goes in pass. side of dist. below the hood alarm switch into wiper valley. Replacing most of engine side w/ hose will normally fix. OR
2) The vac. switch itself is not switching due to vac. leak as the usually plastic rivet is not holding the 2 main switch parts together well. Besides replacing, it is also possible to tighten this &/or disassemble to lube w/ a thin layer of white lithium grease to fix. Try pressing the 2 halves of the switch together to test in A/C or VENT w/ engine running.
3) If you have a heater, the small vac. tube to heater hose valve under hood may be damaged from heat & need replacing. Block w/o heater.
PS The design problem comment is not intended to be offensive to any of our northern friends.
I wrote this up awhile back for this problem & many have used it to fix the system.
On at least later C3 the problem is that heater is the default position (no vac. or vac. leak) due to being designed in the north. Vent should be default. Very safe bet the problem is 1 OR 2:
1) The vac. line from engine may be damaged from heat - a small plastic tube that goes in pass. side of dist. below the hood alarm switch into wiper valley. Replacing most of engine side w/ hose will normally fix. OR
2) The vac. switch itself is not switching due to vac. leak as the usually plastic rivet is not holding the 2 main switch parts together well. Besides replacing, it is also possible to tighten this &/or disassemble to lube w/ a thin layer of white lithium grease to fix. Try pressing the 2 halves of the switch together to test in A/C or VENT w/ engine running.
3) If you have a heater, the small vac. tube to heater hose valve under hood may be damaged from heat & need replacing. Block w/o heater.
PS The design problem comment is not intended to be offensive to any of our northern friends.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
Before you get more serious about swapping AC vacuum hoses, purchase the assembly instruction manual (79) and take a look at what is going to be involved. The AIM shows the factory installation, the color codes, and where all the hoses connect. The is a diagnostic page explaining correct function of the various actuators and doors.
Have you been under the console to determine whether anything is actually missing?
Have you been under the console to determine whether anything is actually missing?
Thread Starter
Racer
Joined: Oct 2010
Posts: 395
Likes: 0
From: winterville NC
well Mike I did pull the glove box out to make sure the cold selector was making contact with the switch and I noticed that there is a vacuum cylinder on the right panel there under the dash by your feet and it does not have a vacuum line attached at all and the white line coming out of the firewall is broken and cracked up from the heat I assume...and i have a corvette assembly manual if that is the same thing you are calling an AIM?
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Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Yes, that's AIM, he has 1000s of posts to get AIM, if that doesn't work...
http://willcoxcorvette.com/images/77...ol%20chart.jpg
Last edited by Ganey; Aug 26, 2011 at 04:17 PM.
Thread Starter
Racer
Joined: Oct 2010
Posts: 395
Likes: 0
From: winterville NC
hey guys thanks a million I am gona try and check her out sometime after this hurricane goes thru....it is suppose to hit us around 7 am sat morning here in eastern NC
Last edited by McVette; Aug 26, 2011 at 07:47 PM.
Thread Starter
Racer
Joined: Oct 2010
Posts: 395
Likes: 0
From: winterville NC
I noticed that there is a vacuum cylinder on the right panel there under the dash by your feet and it does not have a vacuum line attached at all prob a stupid question but what is this used for??
