Bouncing Spedometer Needle?

[Jeff Wilk]

What is the cause the cause of a bouncing speedometer needle in our '59?  It bounces wildly between 0-20mph then smooths out.  Same condition whether accelerating or slowing down.  Also makes a bit of a rubbing noise with a quite squeal while doing the bouncing.  Any cure here?  Thanks.

[TJ Hopland]

I don't know if you have cruise and if you do I don't know the design of the 59. 

On my 'new' 81 the needle would bounce like you describe.  I did not think much of it till I was working on trying to get the cruise to work.  Its got a little gear box on the fender the speedo cables run through.  I took the box apart trying to repair it (unsuccessfully) but after cleaning it and putting it back together the needle quit bouncing so it must have been something in that gearbox causing it. 

Again I know nothing about a 59 so it was just a guess. 

[Jeff Wilk]

GREAT question.  Never thought of that as important, but YES the car does have Cruise and it is not working.

[The Tassie Devil(le)]

Firstly, a "bouncing needle" is caused by a couple of possibles.

(1)   The inner Speedo Cable is dry and requires lubrication.

(2)   There is a kink in the inner cable that requires either straightening, or replacement of cable.

(3)   There is a broken wire strand in the inner cable which is catching on the outer.

(4)   The outer cable is kinked, and requires straightening or replacement.

(5)   The Speedo head odometer gear shafts have dried out and require lubricating.

(6)   The Speedo centre magnetic drum has slipped on the needle shaft.

The Squealing noise could be from No. 1, 4, and 6, and if left for too long with No. 6, is not good.

As far as it only happening at the slower speeds leads me to think that the inner cable is dry-rubbing and as the car speeds up, centrifugal force smooths it out.

I had a speedo that had sat in a car, unused for many years, and when I put it in my car, it went okay for 20 Kilometres, and as the dried-up grease got hot, it started to cause friction on the odometer cross shaft, and proceeded to destroy the nylon teeth.  When it eventually wore sufficiently to skip a tooth, boy, the needle swung all over the place.

Bruce.

[Roger Zimmermann]

On my '56 Sedan de Ville, the needle is stable up to 120 km/h (75mph). Over that seed, it takes about the whole scale...This is the alert for me that I have to slow down!
Yesterday, we went with that '56 car to our vacation house which is at about 600 km from where we are living. Therefore, to shorten the time on the road, I'm always tempted to drive rather fast for such a grandmother...
I'm wondering if a new cable would improve the situation?

[52Cadillac]

Good post. Which leads me to ask is there a kit for rebuilding or repairing or speedo heads, and cables? In my case a 52. And who would sell the speedo gears? Seems to me that all the common gears, etc that will break could be assembled by those in the know.
Mike

[The Tassie Devil(le)]

I don't know of any rebuilding kits, as down here, there is nothing like that.

I rebuild my own, and most times it is just a matter of cleaning, re-lubrication, and resetting.   If anything is broken, then that is a problem.

We do have places down here that do make up Speedo Cables to order.

Bruce.

[n2caddies]

Hi Jeff
I am installing the speedo cables on my 60 cruise today so I will be a bit more educated by days end but I have the cables here on my bench and pulled the inner ones out to find them dry but not kinked or unraveling. I put some multi purpose grease on a shop rag and pulled  them through for a nice coat and put them back into their outer cables. They spin by hand very nice now. Not sure about lubing anything at the cruise unit as I'm reluctant at this point to disassemble  as I'm not sure yet if it works and it has those star shaped fasteners on the housing. In the past I have cured the bouncing needle by pulling the cable out on a non cruise car and greasing it up in this manner. Had to loosen the dash pad and prop it up to make the access easier with AC and all. I'm sure the process is the same for the top cable. The one that goes to the tranny will probably have to come out from under the cruise unit.
Randy

[76eldo]

I'd start with lubing the cables. 

Brian

[Coupe Deville]

My 59 speedometer once jumped from 30 to 100 and went crazy. I tighten the cable at the instoment cluster and the problem went away. I think I will be replacing the cable thou. What is the procedure?
Thanks

-Gavin

[Scot Minesinger]

As per Brian, start with lubricating the speedometer cables.  That can work, but it never worked for me, but it is worth a try.  You will likely need to replace the speedometer cables(s) (plural if you have cruise).  Local places make up speedometer cables, you need to remove yours so the shop will know what type of connectors to use, or re-use yours.  USA Parts offers this service.  Plus USA Parts may have a set of speedo cables in stock.  The shop manual will explain how to remove and re-attach.

[David Greenburg]

I don't think it has anything to do with having cruise.  My '59 had this problem until I had the instrument cluster redone, and my '60 has this problem at times, and neither car has cruise.

[The Tassie Devil(le)]

The next thing to check is the Driven gear that is in the side of the transmission.

Worn gear, slipping teeth will also cause the wavering.

Bruce.

[The Tassie Devil(le)]

The only other thing that could cause a problem is the Speedo Drive Gear, which is on the transmission output shaft.   Not sure if this is ground into the shaft, or a plastic gear that is clipped into place.

Another way of testing is to grip the end of the cable (Inner) whilst it is in the outer, with the chuck of a battery drill, and operate the speedo as though the transmission was driving the car.

This way, you can speed up or slow down the speedo and observe whilst not crashing.

It means that someone has to be operating it under the car whilst it is on jack stands, whilst you have your head stuck up under the dash, or elsewhere, watching, listening, and feeling.

Bruce.

[Jeff Wilk]

Thanks everyone. Some great tips. I will start this weekend with a visual inspection of all cables then make sure all connections are tight and move to lube next. The car was apart for 2 years with hanging cables that did get degreased and sprayed many times. No issues after starting it back up and driving for 50 miles or so. It was on the fourth or fifth drive at that point where the dancing needle started.

[The Tassie Devil(le)]

Ah ha............ sounds like the dried-up, and or contaminated lubrication.

When open to the garage/painting environment, you would be surprised just you these parts get messed up.

Bruce.