Speedometer Trouble Shooting

Hello Everybody,
So I am working on my 1977 Cadillac Miller Meteor Lifeliner. The car has been sitting for quite a while before I bought it; the tabs on the car were from 1999! After getting some other issues fixed, I was able to take the car for a drive. I discovered that the speedometer does not seem to be working. As I drive, the speedometer needle does not move. My hopes were that the speedometer cable was broken. I installed a new cable, but that did not fix the problem.
Has anyone come across a similar problem, or does anyone have suggestions on what I may need to do to fix this?
Thank you!
Kurt

Make sure to pack each end of the cable with good clean axle grease or petroleum jelly "Vaseline" to get it primed above anything else. On some of those speedo units, make sure the slot where the cable fits in is not wallowed out...if it is...then your cable will just spin but not register on the speedo dial....same deal with the end on your transmission where it screws on....if it's worn on the tranny side...the cable wont turn period.

If that does not work you will have to have the speedo rebuilt or just grab a new one from the bone yard. There are several shops around that do them. I am sending out my 55 speedo soon.

http://antiquespeedometer.com/

http://www.bobsspeedometer.com/1/120/speedometers.asp

http://www.deluxespeedometer.com/

Just a start.. i have a lot more in my book,but i need to dig out.. Just to get ya started...

Sometimes it can be as simple at picking up a new cable, sometimes they do break.

This is a longshot,but some services when they put tachograph units in the car,disabled the speedometer,does the odometer still work,believe those were not to be tampered with,just a shot in the dark....they wanted us to pay attention to the recording unit,not the speedometer.

more guess work. pull the cable off the head end and see if you can spin it. if you can't get on it with your fingers a stub of cable will be enough to slid in and turn the head. all you need to do is check to see if the needle moves. if it does the problem is not in the head. then check the gear by inserting the stub end in the transmission and try to turn it if you can't then you should be good there. grab the new cable by both ends and see if the crimped on stub is loose on the cable. just rotate your fingers in opposite direction . you should feel resistance and nothing should turn. if all the quick test show nothing is wrong. then put the new cable back on speedometer head first. make sure its seated and watch your routing. you should have a bout a inch sticking out to get the tyranny gear. spin it while some one watches the head to see it's seated in and the needle moves. if it does your good to go put it together. if not push the housing farther on to the head. some times the needle will get dry in the bushing. if that happens the odometer will read but the needle will not. you will need to take it apart to lube the needle judge your ability before starting.

If your new cable is too short, even by 1/2" it will not engage. Check that. It happened to me.....

One other thing, Sorry not going to help with spedo not working, but if yours is not steady, but bounces or floats 5-20+mph while going at a constant speed, usually a lube or replacement of the cable will fix the problem.

Adding on the John's first post

Here's what happened to my Pirsch and how I diagnosed it: (I've yet to fix it though).
I had a new cable made up although I now realize that wasn't the problem.
Take the cable off the back of the speedo. Drive around and watch the end of the inner cable (you can hold the outer cable in your hand). The inner cable has 4 sides designed to fit into the back of the speedo at one end, and in the tranny at the other. If this cable spins when it's not hooked up,..but the speedo still doesn't work when it is, here's what happens:
There is a device on the tranny that the speedo cable attaches to. This is like a small collar the 4 sided (inner) cable fits into. Back to driving: needle not moving; means that collar on the tranny is broke and basically doesn't spin when pressure is on it. Why did it work when you held the cable in your hand? Because there was no physical resistance....it was just in mid-air. I'm told it's not a big deal to replace - I just never worried about it. The title says the odometer is inaccurate so .....As you can see from all your answers, there are many possibilities. Keep pluggin'

Good evening everyone! Thank you all for your help and suggestions; I really appreciate it! I finally had a chance to spend some quality time with the ambulance tonight. I disconnected the speedometer cable at the transmission, and then I removed the speedometer from the dash. Once I had the speedo out, I stuck the square end of an old piece of cable in the back and turned it to make sure the needle moved. It did, so I know that end is not worn out and the speedometer is good to go. I packed the end of the cable with axle grease, and put the speedometer and dash back together. I then checked at the transmission where the cable fits into the housing, and again using a piece of cable I tried to turn it. I was not able to, so I don't think that is wallowed out. I packed that end of the cable with grease, then I made sure to insert the cable at least an inch. When I got everything buttoned up,it was too late to go for a test drive. I will try to take the car for a drive tomorrow or Monday to see if my problems are fixed. Here's hopping!
Kurt

It is good that you didn't drive it. Remove the grease from the speedometer end of the cable, since it will work itself into the speedometer head, and that is not good. Once the grease gets into the magnetic cup assembly, the speedometer will stop working and it can possibly render the speedometer unrepairable. Speedometer cables are shipped dry of lubricant, and that is because there is an inner liner in the cable housing that is made of a special plastic that is designed to give the speedometer drive cable a smooth surface to ride on. What causes speedometer cables to go bad is usually a kink that causes the cable to break a strand. That broken strand will then start to catch and eventually jam into the inner sheath. When this happens, the lower part of the cable will still be turning, and the cable will break in half, or it will strip out the gear in the transmission. If you are insistent on lubricating the cable, the it should only be lubricated from the transmission end, and only with a light lubricant such as Vaseline petroleum jelly very sparingly.

Nailed It

Kevin nailed it. It's a common problem on Caddies. I had the same prob on a '59, '62 Cadillac Coupe DeVilles and Hearses. Bought multiple speedo cables (the generic kind do not always work, had to find Cadillac NOS). Incidentally, the o-ring on the transmission is also a common source of fluid leak so, don't forget to change it for new. Best of Luck!

Problem Identified!

Hi Everyone!
It's been a while since I have had time to dig into this problem to do some more investigating. Thanks to a few mild temp days, I have had a chance to get into the garage and dig deeper to find out just what the problem was. What I found was that the speedometer gear in the transmission was worn down to the point where the drive gear on the transmission did not seem to be making contact enough to turn the gear.
https://lh5.googleusercontent.com/-.../wKueGzaHFTI/s640/IMG_20130324_191054_609.jpg
I know it's a little hard to see in the picture, but the center of this nylon/plastic gear is worn down. After much searching, I found a great source for transmission parts, specifically speedometer gears! A new gear, o-ring and seal only cost me $15. The company that I ordered from is PATC Transmissions in Bossier, LA. The new gear looks MUCH better than the old one! And I am thrilled because I am 99% sure this is what my problem was. Now I can drive confident, and without the lights and sirens as Mr. Carlin had suggested earlier!
Thanks again everyone for your help!
Kurt

what is the tooth count on that gear. it's stamp on the edge of it

This gear has 41 teeth.

thanks Kurt now for the hard part I can't remember the tires size on that set of years. seams like my 89 limo had the 225 x15s and i'm guessing your car still has the th400 in it or at least the gear looks the same.

I'm asking because we were trying to figure out the right gear for the older cars running the 235 x15 tires instead of the 890x15.

we put in the at 42 tooth gear in this 69 of Paul's but as of yet I have not been able to take the car out to see if it reads correctly.