The Stovebolt Site Forums The Shop Area Engine Shop Speedo Ideas???

38 Coupe rolling restoration. The interior is 95% done. The speedometer starts jumping when I get just over 55 MPH indicated. Since the coupe had been sitting in a barn for nearly 30 years before I rescued her just over a year ago my thoughts are there could be two possible problems. One is it's an accumulation of dust & removing the speedo for a good cleaning & lube is required. Two is the cable needs lubed. Both are probably a good idea however before I can do either I have to remove the speedo cable. I'm having trouble getting cable loose from the back of the speedo. Every speedo I've worked on in my life had a cable that simply pulled out of the speedo after the cable housing had been unscrewed. I can't get this one to release. I can get the housing unscrewed but the end of the cable won't release from the speedo. I'm scared to pull too hard for fear of breaking a difficult to find & expensive part. It's also very difficult for me to get under the dash to see what is exactly going on. I'm not called Tiny because I'm small. Is there a clip or someting simular holding the cable in the speedo even when the housing is loose? If so how is that clip released? If necessary I can pull the seat so I can get my tall, well fed self under the dash but I'd really not have to do that! Ideas?

I can't say for sure on the cars, but trucks of that year just unscrew and pull out like every other cable. Try spraying some oil up there and letting it set for a bit. Joe

Tiny,

Without being 100% sure I understand what's going on, would this be worth a shot.

Somehow, whether by running the car in reverse while on stands, or with the cable pulled on the transmission and a Makita drill running the cable in "reverse", loosen the knurled nut on the back of the speedo and wiggle/pull while all this is going on.

My thinking is that the little square or hex that fits into the back of the speedometer might have made it own little retaining groove over the years. Wiggle wiggle, pull pull!

Stuart

Hi Stuart,
That sounds like me just trying to get under the dash. I've never seen a cable that had a clip on it but I've never had a '38 cable out either. My old '55 1st panel had the standard square shank that stuck into the speedo & was held in place by the threaded housing. I'll try the gentle tug with a little wiggle thrown in again. The difficult part is not being able to see what I'm doing. I like doing some things by touch but that's not one of them.

Tiny,

Is it too early in the new year to ask if the headlight situation was resolved...it's right next to the speedo, so it's almost pertinent to this thread.

Stuart

I haven't pulled the ammeter yet but it seems there is a loose connection there somewhere. The fuse hasn't blown since I cleaned the headlight bucket grounds but on occasion the car will shut off as if the key was turned off. Just touching the back of the ammeter and/or the wiring will cause the connection to return to normal. It's been warm enough to work on the car but I have to pull the seat to get to it & it hasn't been a large enough problem to warrant that yet. To make a long answer longer it seems (keeping fingers crossed) that the headlight problem was a bad ground pulling too many amps across the fuse.

I don't know about your 38, but I did disasemble a '36 speedometer years ago. My memory is that it was the same design as a 60's era speedometer that I took apart to see what they looked like.

You might try disconnecting it at the transmission to see if you can pull the cable out from there. Then, provided the nut has been removed from the speedometer, you should be able to wiggle the cable housing loose from the speedometer.

Just a guess, hope it helps...

I had the same problem with the 41. Took everything appart cleaned and oiled it. Than I bolted in a new speedo cable.

Stil jumps

There is a little magneto in it that pulls the needle. Over the years it lost his power. I found a shop that did nothing but old speedos. Took them half an hour to fix and recalibrate it

Frank

I was going to ask you where you got it fixed then I saw you are in Germany. I'll look for a speedo shop in the area in case the same happened to mine. Mine also makes a noise when it starts jumping almost like gears not meshing quite right. Did yours do that too? :confused:

Yeah, it was sometimes screaming like a burning cat when it starts jumping. But I think the noise came from the old cable.

Try to lube the cable first.

An old hand told me a trick.

Remove the cable from the tranny. Turn it with a drill (I forgot wich direction - you have to try) and while you do this feed WD40 or similar stuff to the cable. The cable works like a thread (if you got the right direction) and "pumps" the lube upwards.

Good luck, Frank

Makes sense, follow the twist of the cable and let it work like a grain auger. I'll try that first.

Or take it to a Speedo shop and have them work on it. Couldn't hurt, they could recondition it while they're at it.

I finally shiped my 47 speedo off to Scott's Speedo service in Michigan, did a first rate job and turn around time was quick. Check out their web site www.scottspeedometer.com

I'm going to second Jim's recommendation of Scott's. They do nice work.

Do you remember what they charged? Thanks.

Tiny, Looking for my reciept, but I think it was around $100. They should be able to give you a quote via email or by phone.

It seems like I paid $150 or $165 or something in that neighborhood.

If it is making noise, then it is the cable. Speedo heads don't make noises unless they are self destructing, and yes I've had that happen. You just need to work on the cable to get it loose. It is only held in by the threaded ferrule.

Speedo heads can be cleaned and rejeweled by almost any speedo shop. If the permanent magnets need replacing, they will do that too. They can recalibrate it quite easily also.

After doing all this, the can check to make sure that your speedometer is reading correctly when it is reinstalled in your car. Sometimes people swap in different speedo gears/rear gears/etc., so it is nice to have a speedo you know works correctly with your car.

OK, thanks! I'll take Stuart's advise and do more of the "wiggle, wiggle, pull, pull" on the cable. As I initially posted I don't want to break it & wasn't sure if it was held in place mechanically after the housing was unscrewed. Now that I know it isn't here comes the prybar....Just Joking.

Well, I didn't have to use the prybar. The cable just fell out this time when I got the housing loose. A good lubing using machine oil didn't solve the problem though so I guess it's time to see of there's a speedo shop in the area. I never can get it to work the "easy" way.

Speedo update, I got the speedo out today & used my cordless VS drill to spin her up to just over 55. Regular as taxes she started jumping so it's off to Scott's this morning.

Speedo update number two. I got the speedometer back from Scott's today and got it put in (THAT was FUN). It was too late to take her out for a shakedown today so I'll do that tomorrow. The worst part was getting the bill! WOW!!!! :mad:

Tiny,

We await with baited breath...how much?


Stuart

$275 and that didn't include any repainting because I wanted to keep the pateena (sp?). AND I have to pull it back out and send it back because it wasn't calibrated correctly. It's 10MPH off. This is not at all what I'd hoped for. Oh well, no rest for the wicked I suppose.