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New to the Forum- Got a Speedo Question

Started by iamCrom, February 09, 2020, 10:20:03 AM

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iamCrom

Hello.
I recently purchased a 65 sedan deville.  Yesterday I went to replace what I thought was a broken speedo cable, but it now looks like like the speedo is what actually broke.  Do you guys have any recommendations for places who can do a rebuild or places with rebuilt units?  I cant really find anything other than ebay specials which dont really state condition and I'm also a bit skeptical.
Help is appreciated.
Thank all.

Oh, and one more question: Is there a way to bench test the clock?  I'm hesitant to just hook it up to 12v.

Cadman-iac

#1
I'm not sure where you can get a speedo repaired anymore.  I used to send them to an authorized Delco repair center when I was still working for a dealership.
There are also independent companies that do this,  and I've used a couple of them.  However the one closest to me has since closed.  Someone else may have a suggestion for you. Not knowing where you are located doesn't help.

As for your clock, it's perfectly fine to connect it to a 12 volt source. If it has just one terminal,  its cut and dry.  However if it has two,  you need to determine which one is the power. You can check the connector for this,  as it should have 12 volts to one of them,  unless the fuse is bad. The other terminal is usually for the bulb in the clock, and it would only have power if the lights are turned on, unless you have one that the bulb socket plugs into the back of the clock separately,  then that second terminal is a ground. Most all of the clocks I've seen used the housing as a ground. You can check your vehicles schematics for confirmation on that.

Once you hook up the power,  there's usually only one of two things that will cause it not to work.  The  electrical side, or a mechanical issue.

On the electric side,  I've found that the most common problem is with the points.  Either no power can pass,  or just not enough for it to work. A good file will fix this problem, but it must be a very small one.
Another issue could be with the coils. These use magnetism to pull a bar into position and pull on the main spring.  There are a pair of ratcheting pawls, one on each side,  that grip a toothed wheel, a gear, and the spring pulls back against it each time the points close and the bar is flung into position.
The wire for the coils can become overheated to the point of failure. I've found that it usually happens near where it connects to the points,  so it is usually visible.  And I have repaired these by simply unwinding a loop or two and reconnecting it.
After doing this,  you will still need to find the reason for it or it will probably happen again.
As for the reason,  that can be a couple of things. The first is that the clock is jammed or stuck. The points close, the bar starts to swing, but cannot travel far enough to break the contact on the points at the end of it's travel.  The points remain closed and the coils and wire overheats.
Another reason I've seen is that the teeth on either the main gear, or on one or both of the ratcheting pawls are worn. This will cause the bar to swing into place,  but since the teeth are worn,  it will simply slide back from the spring pressure and close the points again and just keep cycling until either it eventually will hold, or the coil wire will burn in two. You can tell if it's flipping back and forth because you can hear it very clearly. Sounds like a buzzing noise.

As for the mechanism of the clock itself, it's almost identical to any wind up clock. The only real difference is in how it is wound up. In the car, it uses electricity.

I used to play with electric watches when I was young, as they fascinated me. I had to know how they worked.  I just took what I learned and applied it to the clocks.

  One thing to be careful about is in how you take it apart. On some,  the bezel is  only crimped on in just a few locations,  making it easier to get it open.  Others have been crimped in more places,  and I've had a few that were crimped completely around it.
I'm guessing that yours is square or rectangular,  and those are usually only crimped in a few spots. Usually!

I have had good luck in my own repairs, and I would encourage you to at least look at it.  You may not be able to fix it yourself, but who knows,  you might suprise yourself. The hardest thing to fix is the mechanical part, simply because of the intricate nature of the device. But it's not impossible.

Posting in pieces. Did this once and got logged off.
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

iamCrom

Holy Moly this is is a great response!

Thank you for the info on the clock.  I'll start messing with it tonight.

I did find a place in Seattle who advertises that they rebuild instrument clusters, so I'll contact them on Monday.   Unfortunately, it doesn't look like I have options here in Reno NV.

Cadman-iac

#3
Quote from: iamCrom on February 09, 2020, 04:19:44 PM
Holy Moly this is is a great response!

Thank you for the info on the clock.  I'll start messing with it tonight.

I did find a place in Seattle who advertises that they rebuild instrument clusters, so I'll contact them on Monday.   Unfortunately, it doesn't look like I have options here in Reno NV.
Yes, the weather is lousy here right now,  so I'm stuck in the house with plenty of time on my hands.
Glad to be able to help. If you have any questions about the clock,  feel free to pm me if you'd like. I'll help as best I can.
Rick

PS: I don't know if this is still something that a dealer would do anymore,  but  I  used to get customers ask me on occasion where to have a speedo repaired, and at that time the Delco repair centers would accept a non-warranty job like that. You might want to check with your local dealership if they can either send it out for you, or if you can send it to the facility yourself.  But I would call them before sending it just for verification.
There was a Delco repair center in Phoenix,  and I don't think that they would have closed it. If memory serves,  there was also one in Reno.  But I've been out of the business for years now, so I don't know for sure anymore.

Also, just to check,  did you verify that the cable is spinning when the car is moving? It may just be one of the plastic gears in your transmission. They can strip teeth from one or the other if the cable should lock up for any number of reasons. Also look at the end of the gear that the cable goes into and make sure that it is square.  It can round out and not drive the cable as well.
Just something easy to check before you pull the cluster out.
A simple check to verify your cable is good, is to spin the transmission end of your cable while someone is watching the speedometer to see if it moves. Just be sure to turn it counterclockwise. If you turn it clockwise it's possible to unwrap it inside the housing if something is jammed.

Good luck with your repairs.

PS:  I finally remembered the name of the other repair shop I had used before.  Their website is:
www.dicksspeedotach.com
480-994-9022
They are located in Phoenix.
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Jay Friedman

1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."

iamCrom

Cadman and Jay,

Thank you for the information.  I did manage to find a place in my area that has a great reputation for repairing speedos.  I brought it to them this morning and they think it will be done in a couple of days. 

Cadman, everything is turning OK as far at the cable, the speedo clearly had something loose inside it and when you turned it, you could hear metal on metal grinding.  The guy at the shop said it sounded like the gear went out.

Again, thank you both for the information.  Really appreciate the help.  I'll follow up if I find out anything noteworthy on the clock repair.

MDHusker01

I had a similar problem with my 1950 Caddy. Cable was twisted off. When I put the new cable in, it would not turn. Time to pull the dash panel. I disassembled the Speedo carefully. The lubrication in the mechanism shaft had dried and was very tight. I used a little kroil oil and worked it in. By the time I was done, I could put a drill on the cable and see the needle deflect. It's all back together now, but to be honest, I haven't had it on the road to see if it's halfway accurate. I have not reason to think it's not! Here are some photos.

https://www.dropbox.com/sh/st01hw7cp19y51a/AABu5jgiAU1T_9HlvQCoVmPVa?dl=0

iamCrom

Those are some great pictures of the repair.

So I picked up the speedo and was also given a bag of parts.  Apparently, it basically exploded and luckily the repair shop had spare parts to put it back together.  Cost me $250, but it works great and he had it done two days after I dropped it off.

I took advantage of the dash being apart and replace all of the bulbs with warm colored LED.  The dash looks great and hopefully I'll not need to change out a bulb for many years.

Cadman-iac

Good, I'm glad you got it fixed without too many problems. Did you get the clock working yet?
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"