1964 Speedometer intermittent problems

[Gary Tayman]

Can somebody explain this one?

About 6 months ago I was driving home at night, and glanced down and saw the speedometer wasn't working. Before I made it all the way home, it had started working again.

Today, 6 months later, I was driving home and it happened again. Glanced down at the speedometer, and nothing. It didn't return but I was only driving about 5 miles. What I DID see, the odometer also was not moving.

So I suppose it can be three things -- something in the cluster, something in the transmission, or the cable itself. I can't see the cable itself doing this if it starts working again, but I'm wondering what would do this. Has anyone else seen this problem?

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[fordrodsteven]

My understanding of speedometers is as follows. The transmission to cable connection is a mechanical connection as is the cable to rear of the speedometer. The inside of the speedometer, as I understand it has a magnet and cup (with some sort of drag on it for smoothness) within a small gearbox that moves the needle up to read MPH. My guess would be that the problem is most likely in the speedometer at that location. Maybe dust, dirt or rust interfering with the function of the magnetic drive portion. I think that same mechanism also has the connection inside it to the odometer to turn the number wheels. I'll do some more research but at this point that would be my best guess regarding your issue.
If it was a binding speedometer cable you would see the MPH needle bouncing up and down as you drive. I have even seen them drop to zero then bounce all the way to top speed then settle down for a mile or so then drop and bounce again. Replacing or lubricating the cable fixed those issues.

https://www.explainthatstuff.com/how-speedometer-works.html

http://www.mustangandfords.com/how-...mp-0606-calibrating-ford-mustang-speedometer/

 

[biddle]

Updated your title from
"1964 Speedometer"
to
"1964 Speedometer intermittent problems "

A detailed title is vital for more responses. 1964 Speedometer could mean anything, i.e. you are selling one, want to buy one etc.

 

[Gary Tayman]

I've had this thing out before, albeit many years ago. The speedometer cable is geared down to drive the odometer directly, then there's an air coupling -- I forget if it's magnetic or fan or what -- that rotates a drum, which looks like a barber pole. Remember, this is a 64 and the speedometer looks like a horizontal thermometer.

The problem has to be one of three things -- coupling at the transmission, coupling at the speedometer head, or the cable itself. Ironic, this car originally had cruise control, but I replaced the two cables with a single cable that bypasses it -- did it years ago. if I still had the two, I could disconnect one, install it into an electric drill, and see if the speedometer moves. But -- oh, well.

 

[fordrodsteven]

I would suspect the concept is the same except the magnet and cup are at the end of the cylinder to turn it for speed indication. You seem to be of the opinion that the odometer is a more direct connection. Is it possible the cable may be just a hare short and is disengaging? I should think you could still use the cable in the car to spin it with a drill by just disconnecting at the transmission end. While I had it disconnected I would also try to move it in and out to see if the length of it checks okay.

 

[Gary Tayman]

I would suspect the concept is the same except the magnet and cup are at the end of the cylinder to turn it for speed indication. You seem to be of the opinion that the odometer is a more direct connection. Is it possible the cable may be just a hare short and is disengaging? I should think you could still use the cable in the car to spin it with a drill by just disconnecting at the transmission end. While I had it disconnected I would also try to move it in and out to see if the length of it checks okay.

Thanks; one of my dealers is a shop that specializes in gauges and clusters. I called them and was told it could indeed be the cable not quite engaging. They said it's nearly always the cable disengaging or the speedometer itself. I'm not the kind who can crawl under the transmission and fiddle with the cable, and after four shop visits this month alone (two on a tow truck), I'm not exactly eager to drop it off yet again. I just might forget it for the time being, take it only to a couple of nearby shows and an errand here and there (to see if they've fixed the OTHER ISSUES!), then plan on a time when I'll have the steering column rebuilt again, and maybe have them work on the speedometer at that time. I think it's slightly off anyway, I just might send it off to this shop or a rebuild. In the meantime if someone wants to install another cable itself, inexpensively, I'll take him up on it.

 

[BigClay]

Can somebody explain this one?

About 6 months ago I was driving home at night, and glanced down and saw the speedometer wasn't working. Before I made it all the way home, it had started working again.

Today, 6 months later, I was driving home and it happened again. Glanced down at the speedometer, and nothing. It didn't return but I was only driving about 5 miles. What I DID see, the odometer also was not moving.

So I suppose it can be three things -- something in the cluster, something in the transmission, or the cable itself. I can't see the cable itself doing this if it starts working again, but I'm wondering what would do this. Has anyone else seen this problem?

I just saw this.....sorry for the late response. I had the same problem with my ‘64. Turned out to be a missing tooth on the plastic drive gear on the end of the cable in transmission. I replaced the gear (from The Bird Nest), and it works perfectly.