Question: Hi. I have been a longtime subscriber and I am interested in asking a question to your Technically Speaking staff. I have a 1967 Corvette and the clock will only work when I tap the face of the clock.
My car has been judged and has an NCRS Top Flight award. I want to keep my car as original as possible so I do not want to have the inner workings of my clock converted to quartz.
I love working on my Corvette and get great satisfaction when I can fix it myself. My question: Is there an easy repair that I could perform to repair my clock? I don’t like the idea of having to ship my clock through the mail to get it repaired. Thanks,
Bob, from Florida Answer: Bob, the internal workings of the 1963-’82 Corvette clocks are similar. The original Corvette clocks are analog, spring-wound with an electric winder that is supposed to reset the spring mechanism approximately every minute. This electric winder depends on a set of 12V contact points to close every minute to reset the winder 24 hours a day, seven days a week. That’s over 525,000 times a year.
When the contact points close a coil will kick the points open, giving us this one minute of run time before the process repeats itself. If the coil becomes weak, the points will not kick open as far, giving a shorter run time between kicks. To test this, if you have the clock apart, you can power it with 12V and a ground and watch this process and see how long it takes between the kicks. If the clock is installed in the car you can hear a click every time the coil resets the winder. Remove the Clock From the Dash
It’s not hard to get the clock out of the dash. If you have large hands or don’t like to work without seeing what you are doing you will probably be more comfortable removing the glovebox and glovebox liner. On a restored car, the less I need to remove means the less that can become damaged so I simply loosen up the glovebox liner and move it back to give me enough access to put my hand in there and reach the back of the clock.
You will need to unplug the clock’s two-wire connector and then remove the two light bulb receptacles by gently pulling them out. The clock is held in place by two clips. With your hand, find the clock retainer clips and push the end down and slide it off of the clock’s attaching knob. Gently pull the clock out of the dash. You may need to slightly angle the clock so the raised area where the clock is staked together does not damage the dash paint when it is removed.
Accessing the Clock Mechanism First, note how the clock is aligned, you may want to take a sharpie and make a mark on the rear housing where the 12 o’clock is indexed on the front housing. The clock’s chrome set screw will need to be removed, hold the black part of the stem with a pair of pliers and unscrew the chrome set screw counterclockwise with your hand. If the set screw will not move by hand you may need to use a second pair of pliers to remove the chrome set screw.
Use a pair of small needle-nose pliers or a flat-blade screwdriver to open the crimped areas where the two halves of the clock housing are attached. Carefully separate the two halves. You may need to use a pocket screwdriver to gently pry up the inner section and start the process.
The power terminal will need to be removed. Before removing, mark and take note of how the terminals are aligned. They will need to be put back in the same place so the clock’s power source plug can be attached correctly.
Common Problems The contact points build up corrosion over time. You can take a points file and file the corrosion off of the points. Be careful not to file the points themselves too far down. Note: If the points need to be replaced, I have cut an RCA jack end and soldered this in place of the points. You may need to grind the edges to get it to fit. Also, don’t use the rounded edge of the RCA jack. Remember, the original points were not rounded. Clean the mechanism with some aerosol air dust cleaner like you would use for your computer keyboard. Then, sparingly use some light clock oil to lubricate the mechanism.
The most common problem I have found is that the rivet that holds the ground lug onto the back of the clock becomes loose and will need to be restaked or replaced. Before reattaching everything, you may want to plug the clock in and check to see if it is keeping accurate time. There is an adjustment for speed next to the oscillating wheel. There you will find an oscillating wheel handle, moving this handle slightly left or right will adjust the speed of the clock. To check the speed of the clock you may want it to run for several hours and check its accuracy.
If the above did not repair your clock you will probably need to send your original unit out to an expert for repair. You could also replace the mechanism with a quartz conversion. The quartz conversion is more reliable and will keep time more accurately. The only disadvantage of the quartz conversion is that it is not original and you will be penalized if you have the vehicle judged by the National Corvette Restorers Society (NCRS) or Bloomington Gold.
Bob, if you decide to go with the quartz conversion I’m sure if you have some patience that this is something that would make a good do-it-yourself project. Besides ordering the quartz mechanism conversion, I would recommend ordering some correct needle paint, bezel paint and a new lens, and possibly a set stem knob if it is worn due to time. If anyone needs a quartz conversion procedure let me know and I will try and do an article. Thanks and good luck. Vette
Photography by James berry