This may be common knowledge but it was new to my experience so I thought I’d post it. The rally clock in my 68 XR7 had worked faithfully for years until I recently took it apart to make some minor mods to the clock face. Of course, even though I didn’t touch anything else, the clock mechanism stopped working. After about four or five attempts at cleaning, fidgeting, and otherwise blindly tinkering, it struck me that the relay mechanism that winds the clock spring is grounded to the case by a metal collar that circles the positive lead post. If this collar isn’t pressed tightly against the back of the case when the clock is assembled, the relay gets a poor ground and doesn’t have the juice to wind the spring. The collar rests on rubber grommet that insulates the positive post. This grommet had shrunk/hardened from age and even with the clock face snapped tightly into place, no longer sandwiched the ground collar tightly enough. One option to fix this would be to replace the grommet. My cheapskate solution was to use a small ball peen hammer (yes, I realize a hammer seems an odd tool to use to fix a clock) to slightly bend inward the opening in the case through which the positive terminal protrudes. Doing this made the clock face cover snap on much tighter and the clock has worked perfectly ever since. Total cost of repair: $0.00.
Awesome, I love a free repair. Thanks for the post, I’ll have to look at my clock. Although at this point, I think a may neec bfh 
Two other things to know about these old clocks:
Use 3 in 1 oil or other light oil to lube every bearing in the mechanism. And this is the really important part. Use a blow gun on your air compressor to carefully but thoroughly blow all of the excess oil out of the mechanism. I wrap the back side of the clock in an old rag to catch the oil as it is blown off the parts. This will leave just a very thin film of oil where it needs to be. I learned this technique from the watch repair guys in the Jewelry store I worked in as a kid.
The clock is wound every time a set of points close and fire a small solenoid. Carefully file the points flat and remove any oil from the contacts with some rubbing alcohol. These two things plus good grounds can keep you clock working for years.
Did you know the clock is self regulating? If the clock is slow, when you advance the hands to the correct time ALWAYS turn the time forward. This applies a very small correction to the speed of the clock. IF the clock is fast, always turn the hands backward to the correct time. The clock wil never be super accurate, but over time it will get closer to being right.
No, I didn’t, very intriguing Bill! Any tech stuff to look at on this?
Also, if you have a chance, please see my tale of woe re:car audio on my ECI thread (here). Hoping you as an audio guru might have some thoughts?
Thanks,
Bob
Thanks for the tips. My clock seems to work but very very slow. It’s only moved about fifteen minutes this year. Maybe between the points, ground and oil it could get back to normal. Does anyone have reference pictures?
Steven
Sorry I didn’t take any pics but it’s pretty easy to figure out what’s what after you open it up. It’s one of those projects that you can actually do sitting in your easy chair in the living room watching tv. Unless you use the hammer incorrectly, you really can’t wreck anything by just taking the back cover off.
Thanks, this gives me something to go on. Between the info you and Bill posted I should be ok. Heck my clock can’t be any worse than it is now.
Steven
So my symptoms are as follows. My original mechanical Rally Clock (68 XR7, console mount) runs for only a few minutes and only after I manually adjust the minute hand. Sometimes it runs longer and I can hear an occasional “click” (maybe every 90 seconds or so) which I assume is the solenoid firing and tensioning the spring. Sooner or later, no click and the second hand stops.
So two questions:
First, basic removal. Once I pull off the console pad, can I remove the clock from the front? Or do I have to pull the whole console and get at it from behind?
Second, and more in line with this post, is this likely a lubrication, contacts or grounding issue? What should I look to work on first???
Thanks for the help folks!!
Mark
The clock is attached to the pad so once you take that off, simply unplug the wires from the clock and remove the three nuts that hold it to the pad and you can take it into the kitchen or wherever to work on it. One of my parts clocks did what you are describing and it turned out to be that although the spring-winding solenoid was working, it only wound the spring a tiny bit-- just enough for about a minute of ticking. Cleaning the contacts, oiling, and cleaning didn’t help. My memory could be wrong on this but I seem to recall that the issue was that the little arm that held one of the relay contacts wasn’t getting a good ground through the chassis of the clock. I suspect that as the pivot wears, electrical resistance increases, even more so if oil gets in there. Less juice means the relay clicks with less force which, in turn, means the spring gets wound less and less. In any case, what fixed it for this particular clock was soldering in a small jumper wire from that arm to the chassis of the mechanism to insure a good electrical connection.
Well I finally got around to pulling the clock, and with a lot of help from my forum-friends, I now have a well-functioning clock again.
For my clock, I think the only problem was 45 years of neglect. I was able to disassemble the clock from the housing, clean and lube (3-in-1 in one hand, compressed air can in the other) and bench test. I’m quite sure that dry gear friction was the source of my problem.
Nice to see that second hand indexing its way around. THANKS GUYS!!!
how did you bench test the clock? my clock isn’t working at all and I plan on doing everything that was listed above but, would like to see it work before I reinstall.
Easy. 12 volt source to the bolt protruding from the back (which comes with a 90 degree boot on it) and ground to the spade connector. Most of these guys probably have a convenient 12 volt source on their bench. I just use a portable jump start battery as the source.