Technical 52' Ford speedo clicking

Whenever I hook up my speed odometer cable it get a clicking while I'm driving. The faster I go the louder it gets. Any ideas what causes that and how I can fix it?

Thanks

 

Your speedo cable may need some lubrication. When they get dry and crusty, the cable inside will hang up momentarily, then release, causing some weird sounds. Does your speedo needle jump or twitch when it clicks?

BTW, welcome to the HAMB. Might be nice to do an intro.

 

Your speedo cable is either kinked or dry or both. Check to make sure there are no sharp bends on the housing and lube the cable. If that doesn't fix it it's likely the magnet in the head is hitting on the armature. That isn't a good thing for the home shop to mess with. If that's what it is, take it to a speedo shop or replace it. Good luck..........
Glenn

 

The speedo needle does jump when it clicks. Do I need to pull the cable out entirely to lube it? And what should I use to lube it? Sorry for all the questions guys, kinda new to restoring old rides

 

Pull the inner cable out and check for any broken strands then clean it good to get any old grease off. Now when you put the inner cable back in just grease the first half as you insert it. The second half will be greased by the excess in the cable. It sounds weird but that is the old school way and it works. If you over lube it can migrate into the speedo head and make a mess.

 

I like to hit them with some graphite and call it done. Even a bit of Lock Ease works good.

 

Hit your local motorcycle shop and get a can of cable lube. Disconnect both ends, pull/clean the cable (checking for broken strands/kinks), and spray lube through the housing until it shows reasonably clean. Reassemble...

 

I've found detaching it at the speedometer head and spraying some WD-40 into the cable will soften the old graphite and stop the clicking.

 

It may not be the cable. Perhaps the speedo head needs cleaning/ lubrication.

 

What would be the best thing to clean it with?

 

On the 49 Ford in the avatar the speedometer was "jumpy", not smooth working at all, in my case the speedo cable was fine (although I did add a little lube when I put it together) but when I had the dash out to repaint it and do the rewire I took the speedometer to a friend of mine that likes working with clocks and watches (and maybe in his younger days turned speedometers back), he took it apart, cleaned the dried grease out and relubed and reassembled, probably took him five minutes as I watched, that speedometer works just like new now.

 

There should be a brass cap over the part where the cable screws on. The old grease hardens up and gets powdery/flakey, so you have to flush it out. I found WD40 or PB blaster works to break it down, then you can lube it with new grease or light machine oil.

 

Its either the cable, the speedometer, or both.

you can drive the car with the speedometer cable attached to the trans and disconnected from the speedometer, if it clicks -> probably the cable (or both), if not -> probably the speedometer itself.

Pull the cable out from the speedometer end (typ. there's a brass collar crimped on this end so you can't pull it out from the trans end) I use lithium grease, grease the cable as you slide it back in, not too much, just enough to coat the cable.

For the speedometer:
They are super simple, but the needle assembly is very delicate, so be careful, not a place to be heavy handed! Take it apart, grease the gears, again I use lithium grease here, and if you can take the main drive/bushing assembly apart - great, if not, due to factory peening, then use engine oil. Use a variable speed drill (don't want to spin the speedometer at the full speed of an electric drill, slow to moderate speed) with a square drive attachment (used for square drive headed screws, they come in different sizes and are slightly tapered) to spin it and get the grease/oil worked through everything.

FYI: mechanical speedometers are very simple and elegant in design. The way they work is: They have a spinning magnet, turned by the speedometer cable. The magnet spins inside a cylindrical shell, which is attached to the speedometer needle. The shell is typically made of aluminum (but any metal will do). As the magnet spins, it causes eddy currents to be produced in the cylindrical shell. Same principle as moving a wire though a magnetic field, but a little different because the current is not confined to a wire, instead it can move in a circular pattern within the walls of the cylindrical shell. At the same time the eddy currents are being produced by the spinning magnet, the eddy currents themselves are making their own magnetic field. This induced magnetic field wants to follow the spinning magnetic field, causing the needle to deflect. A faster spinning magnet creates a larger eddy current, which, in turn creates a larger induced magnetic field, thus the force between the spinning magnet and the induced "magnet" is larger. This force acts against the coil spring on the speedometer needle causing the needle to deflect more as speed is increased. That's the theory, but back to practicality:

Once you've lubricated the cable and speedometer, it will be really great when the needle doesn't bounce around anymore and the needle is nice and steady, like a new car, or like your Ford worked back in '52!

Kipp