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Registered
Join Date: Jun 2009
Posts: 11
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Heat/defrost/fresh air controls stuck...
1978 SC. Of the three controls on the dash, the bottom two refuse to travel to the right and stay there...they spring back to the left. I can keep either of them to the right position by going under the bonnet and manually moving the valve by hand...although this presents a problem while travelling at speed...So do I need new cables or can/should I lubricate the valves under the bonnet?
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11-13-2009, 07:38 AM
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Join Date: Oct 2005
Location: Capistrano Beach, Ca.
Posts: 7,235
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I'd first suggest that you disconnect the cable ends from the valves and see if you can easily move the valve levers--this will tell you if the problem is with the valves, or the cables. If the valve levers move easily, then lubricate the cables in their sheaths and move them back and forth with the dash levers to work in the lube. Reconnect the cable ends and see how things work.
If the valve levers are hard to move in their complete circuit, then, of course, free those up as you originally planned.
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L.J. Recovering Porsche-holic Gave up trying to stay clean Stabilized on a Pelican I.V. drip |
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11-13-2009, 07:49 AM
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Join Date: May 2006
Location: SLC, UT
Posts: 391
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I had similar problems on my SC. Pulled the controls (it's a pain...), left the cables in place. I disassembled the control unit, clean, and lubed it up. Scrubbed the metal switch contacts well also, as they were corroded. Sprayed some lithium grease on the cables, "cycled" them in-out several times and re-installed the unit. WOW, it works so easy now.
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John 1982 911SC Targa ~ Gulf Blue (gone but not forgotten) |
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11-13-2009, 06:38 PM
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Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 4,184
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Quote:
If you're lucky, it'll be as easy as that. One of the flappers on the driver's side can only be moved with some force on my car (so the cable springs back against the resistance as you describe), and getting the spring clip off on the bulkhead side behind the brake booster makes swapping the electrical portion only of the ignition switch look like a breeze. I've tried 3 times to get the box out to fix the flapper valve, but that clip defeated me every time and I finally just set it to direct air to the windscreen for demist and left it there  It's only one valve - and I've yet to be able to examine it to see what its malfunction is, the others move very freely - but no amount of lube has helped more than very marginally... Good luck!
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'77 S with '78 930 power and a few other things. |
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11-13-2009, 07:41 PM
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Might be the cables themselves.
I took all 3 out of my '78, they were stuck inside the sheath from years of non-use. Pulled the wire out, blew out the sheaths, then cleaned up the wire with 0000 steel wool. Squirted a little graphite into the sheaths and reassembled. Smooth as glass now.
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1978 911SC (not black, Mocha Brown) |
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11-13-2009, 10:33 PM
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Mine had the same issue.
I took apart all the flappers and cables in the hood. I actually replaced the sheaths with bicycle sheathes. The are working great now.
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1978 911sc Targa Sold 2001 996 Cab Sold 2006 Cayenne S Silver Wifes Car for sale 2011 Jeep Wrangler Silver for sale 2010 Toyota Prius Black for sale 2016 BMW 328D wagon |
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11-13-2009, 10:47 PM
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Here's a pic
the nice things was getting all the hoses and ducting cleaned out. Tons of junk and dust    fun project you will want someone to help you when you reassemble. That way you get the levers set correctlly when you tighten the cables
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1978 911sc Targa Sold 2001 996 Cab Sold 2006 Cayenne S Silver Wifes Car for sale 2011 Jeep Wrangler Silver for sale 2010 Toyota Prius Black for sale 2016 BMW 328D wagon |
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11-13-2009, 10:53 PM
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1978 Porsche 911SC 3.0l
chocolatelab
