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Willcox: While I greatly appreciate your assistance and advice here and have generally be very pleased with parts ordered from you the "modified to work properly" switch I bought from you arrived leaking--significantly.
After a bit more research I just disassembled my original and barely leaking switch, applied a liberal amount of heavy silicon grease and it has been working perfectly for months.
Mike..not good news on your experience with the Wilcox upgraded-lubed switch..THAT is the part I'M starting with when I AGAIN take the console side carpet-boards and disassemble the console on my '78..
Gotta wonder also IF even quality dielectric vacuum grease will actually stay inside the assembly..unless something additional is done to secure the switch together like the screws and rivets some have used successfully.
That above the tranny tunnel beneath the console even with insulation does get pretty hot..and heat makes even viscous grease runnier..Jim
Half plastic rivet broke not keeping halves together Exploded view note small amount grease in rubber
Great thread indeed..
heres my tale and maybe helpful repair..
1979 L82 w air
blowing floor only,
after tune up i hear a hiss from controller..
carpet peeled from sides remove two phillips screws, remove barrell nuts to remove vacuum lines..
and mine was loose and rivet broke where it was to hold it together..
hardware store 2 bucks later will see...
I have no idea how much paste to use so i smeared the flat part, and residual finger on the rubber..opened up holes..seems all the rubber will do is smear and clog potentially??so lighter better imo
Washers slide around a liitle but not going far Keep height low so vacuum connector fits on good with barrel nuts..
Wound up grinding down 3/4 length screw as it would have hit vacuum lines.
dot of thread locker and tighten to where spring washer is about tensioned
Snug tension all from washer prongs..moves smooth but definitely some grease resistance
Took a washer off and tighten tension washer more...can use 1/2 inch screw now
Very tight when you swing that lever over..screw cannot be too proud..
Success success
blows hard vents defrost heater floor...very cool...now ac compressor r12 next...
good luck to anyone else trying to fix..hope this helps
Really appreciate all these great photos of the later model corvette vacuum control bits! Thanks!
I thought i would revive this thread because it's so great and add some pictures from a 1972 model without AC.
Mine were leaking, and I tried to just take off the clip and put some vacuum grease on the edges, but it didn't seem to work.
I am now trying to figure out which size screw I can use to hold the 2 pieces together, now that i drilled out the rivet.
Seems like if you were careful enough, you could almost drill and tap the specialized rivet, rather than getting rid of it totally.
I've heard people talk about putting an o-ring in there, but what size did you use?
What size screw did you use?
Did you utilize the hex shape where the rivet is? foot/body/windshield air flow selector retaining clip after retaining clip is removed
notice the hex shaped depression where the circular rivet went. Seems like if i could find small nut it may be able to make a tighter seal inside of the 2 pieces channels inside the vacuum selecter specialized rivet
So using the screw definitely worked, but remember it can't be so tight that the 2 wheels can no longer move. I would also put a lock washer on to help prevent the screw from backing out when you turn the **** a few times. It may still happen. Locktite would probably help too.
I also realized that the vacuum grease helped, but don't apply too much, or else the passages get clogged again.
Overall, this helped it keep vacuum better than before, but i was never able to get it to hold the same 15 inches for more than a few minutes.
honestly, I'm not sure if you really need that, or if it was ever designed to do that.
I hooked it back up, and I couldn't tell any different reading on my air/fuel ratio gauge or rise in idle rpm, despite the slight leak. This was compared to the entire vacuum system plugged on the intake manifold.
I also replaced all the hoses at this time and that helped a lot, despite the old ones not being visibly cracked or broken. This includes the one that goes to the rear vent door by the rear window (t top car). There is a metal pipe that runs from the dash back to the rear vacuum actuator, and mine was rusted, broken, and just junk.
that ended up being my most significant air leak
I ended up carefully drilling through the tiny rivet, but not tapping it. Just put a nut on the other side. I could never find an o-ring that would work
Very tight when you swing that lever over..screw cannot be too proud..
Success success
blows hard vents defrost heater floor...very cool...now ac compressor r12 next...
good luck to anyone else trying to fix..hope this helps
Reviving this thread. Your situation is exactly as mine is now. 79 L82 air only blows from the floor vents. I’m not exactly the most experienced at fixing these kind of things but your post has given me the motivation to give this fix a try. Could you give me more info on where exactly to locate this switch? Is it behind the console side carpet panels? Driver or passenger side? Assume it can be removed by a few screws and unhook the vacuum lines? Thanks!!
Reviving this thread. Your situation is exactly as mine is now. 79 L82 air only blows from the floor vents. I’m not exactly the most experienced at fixing these kind of things but your post has given me the motivation to give this fix a try. Could you give me more info on where exactly to locate this switch? Is it behind the console side carpet panels? Driver or passenger side? Assume it can be removed by a few screws and unhook the vacuum lines? Thanks!!
remove seats, remove side panels..it is behind controls..
I pulled mine out last year or so, following interpon’s pics. I don’t think I had to pull the seats, you can push the foam down a fair bit and get at the rear most one. The front two are accessible for sure without pulling the seats.
I used a bolt and nut to clamp the thing together, along with the vacuum grease recommended to help seal. I ended up having to tighten the nut just a bit more than I expected to to maintain a seal, but once I did, the HVAC worked great. I used a hand vac along with some step-down adapters to confirm the unit held vacuum off the car before putting it back on. I believe the trick was to run it in setting 1 (off) and confirm that the two listed ports sealed. Once they seal, you can be reasonably confident the setup will work on the car. It’s also worth noting that my switch, which was likely a reproduction unit, didn’t positively “click” into any particular position once installed. There was a definite notchiness when it was in the right spot, but it required very judicial movement to find that spot.
06-27-2016, 07:44 PM
