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Classic/Antique Car Repair/1976 Lincoln headlight doors


Hi, i have a '76 Lincoln Town Coupe with vacuum operated headlight doors.  When i first got the car the headlight doors would stay shut after shutting off the engine, then open after a few days.  Now the doors close after starting, and open immediately after shutting off the car.  A mechanic told me that there is a black round disk about the size of a half-dollar by the coolant overflow, and that inside this disk is a valve that shuts to keep the doors shut when the car is off.  I found one in a junkyard and installed it but no luck.  The disk has 2 male ends on each side and connects the vacuum hoses on each side.  I was wondering your opinion on this before i go back to the junkyard looking for another disk or start replacing the miles of vacuum hose.



That gadget, the black round disk is a one way check valve and can be tested easily. It allows vacuum to flow in one direction only. Now if you are going to diagnose this system I would advise the purchase of a MytyVac tool. It is a hand held vacuum pump. The check valve should allow vacuum to flow through in one direction and hold vacuum in the other direction. The tool will be a great aid in diagnosing the system.  

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Brad Sears


All automotive including antique and collectible. However if the car has been modified I can only answer in general terms and maybe get you pointed in the right direction.


Automotive tech instructor. Syndicated auto columnist 1970's though the early 1990's. Syndicated auto radio talk show, Ask Brad About cars, CBS Radio 70's through 90's TV Show "Last Chance Garage" 1980's PBS-TV syndicated. Auto instructor for the following companies: Fram Autolyte Holly Carter AMF Ford Motor University Of Conn Blue Hills Technical School Sugar River Technical Center Grew up in a family garage in Needham Mass and turned wrenches from the age of 14.

Manchester Union Leader, Nashua Telegraph, Motor Service Magazine, Yankee Magazine, Popular Mechanics (Saturday Mechanic early 80's), Los Angeles Times, New York Times, and lots more.

More than I care to remember. Basically Franklin Technical Institute in Boston, Northeastern University, Fitchburg State Teachers College, Tufts University, and a lot of factory schools along the way.

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Moto Award winner. And much more.

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