Annoying Speedometer Noise at Cluster

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Wrencher

Wrencher

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Greetings.

I started my '66 the other day to shake the cob webs out, and give it a bath which it sorely needed. I drove it around to get the fluid temps up to normal operating temp and I was reminded of an annoying speedometer noise this car has of which I am not sure how to fix.

Last summer, I pulled the cluster to bypass my amp gauge and install a SS voltage regulator w/capacitor. After putting it back in, I've had this noise ever since. Im not inclined to think that its the speedometer cable because it started doing it all at once. However, it sounds EXACTLY like a dry speedo cable would. I wd-40'd the cable housing and not much to my surprise it didnt make a difference. The cable is pretty free. I think the problem is in the "clock"? not sure what its called.

This car has been in my life since childhood, and as far back as I can remember, the speedo has always jumped 5-10mph while going down the road. Now, its jumping so bad at low speeds its not even legible. It levels out at like 40mph, which is way lower than my actual speed. Any ideas on what I need to be looking for? I've never had the cluster apart so I have no clue what to expect. Also, the odometer does not work, which is another clue (to me) that I have a clock issue. I have no idea how long the odometer hasnt worked. Taking the cluster out didnt change that.
 
You've got a tight bend in the cable, somewhere,

Were I you,, I'd get the cable down to where you can pull the inner cable out from the top,, clean it,, the as you feed it back into outer housing,, lube it liberally with axle grease, or good lube..

Then reinstall the cable to the speedo,, making sure to avoid any tight turns/kinks,, then check the cables path right down to the trans,, easing any bends as possible..

The speedo jumping 5 - 10 mph is the cable binding,, then springing free..

hope it helps
 
I would remove the speedo cable from the head and drive it. if the noise goes away then you have narrowed it down at least. WD40 isn't really a good lube to use on speedo as it wont stop it from whipping in the sheath.
A white lithium or sli-glyde would have been better choices to lube the cable. Remove cable and clean and when sliding it back in coat it liberally as you slide it back in sheath.
 
There's only so many things it can be

Bound up cable from improper routing

Damage to interior of cable housing

Damage to cable itself

Not enough or wrong lubricant

Problems in speedo head, IE worn out
 
WD-40 is a horrible lubricant... not helpful on a speedo cable. I like to use a light-weight grease (white lithium grease or something) Even powdered graphite can be used.....
 
It's probably not the cable at all but the speedometer has dried out. My dad has a spring loaded tool that screws onto the back of the speedometer that he has used for decades when he had his own garage. You fill the reservoir with 3-in-one oil, release the spring loaded plunger and it pushes the oil into the back of the speedometer. Been using it since the 60s to stop the kind of noise you describe and to stop the binding that causes the needle to bounce around. It works great! And, you can do it without taking the dash apart.

Careful, WD-40 will dissolve and dilute what lubricant is already in there.
 
Try using motorcycle chain lube on the cable, it took care of the noise in mine.

On a side note I also had a 71 d-100 one time that bounced like crazy and made noise, the problem was indeed a wore out speedometer, ended up changing it out.
 
There is a specific moly loaded speedo cable lube that you can get and it's made to not solidify in even very cold temps. A moly loaded lifter lube will work well too. Try to find that. Lithium grease is also used but will dry out with heat over a few years and need to be renewed. You need to pull the calbe core out to lube it from end to end.

The speedo cable end may not be fully seated in the back of the speedo housing, and the old lube is making things worse. I have had your exact same problem with a Dart speedo, with the jumping and misreading, and thought it was not the cable, but I finally got it relubed well and the cable end reseated correctly and that fixed it.

If the end is rounded off of the cable core, which is another possible issue, then you used to be able to get kits that can be cut to length with a crimp on new end. I've used those before and they worked fine.
 
I'll get under the dash and see what I have going on. I removed and replaced the cluster and the noise just showed up. I dont know how I would have caused a bind. I will check anyhow though.

The WD-40 is not a great cable lube, I realize, but even to that end, it should have at least made a dent in the noise. Changed it a little, stopped it for a few miles. something......

I have pulled it a few months back and it slides in & out easily. It is dry though. thats when I applied the WD in hopes of changing it. I will procure a better lube and it will get a righteous lube this week. The cable looks to be in great shape.

MoparPhil, your answer seems to make the most sense to me. I only say that because I had the cluster out for a couple days. When I reassembled everything, nothing bound, everything went right back in to place without a fight. If it had any lube in it whatsoever, I think it might have run out while it was sitting in the floorboard. Even if I have to pull it back apart, I will. I just need to figure out how to get lube into the speedometer assembly.

Thank you for all the answers guys. I will mess with it this week as weather allows and report back if/when I find something.
 
OK, so little to my surprise, lubing the cable had absolutely zero effect. I used a lithium grease as suggested by all the WD-40 nay sayers and it had the same exact effect. Same as last time, I pulled and cleaned the cable, lubed the housing and re installed. No apparent binding, the cable goes all the way in with little to no resistance.

As I said in my O.P., I am sure this is not a cable problem as the noise didnt start until after removing the cluster. The noise is localized in the cluster and I still feel that the clock is the problem, has anyone been inside these things? are they serviceable?

Any answers OTHER than the nominal "its the cable" would be appreciated. I ruled that out before posting the first time :)
 
From your OP.. "Now, its jumping so bad at low speeds its not even legible. It levels out at like 40mph, which is way lower than my actual speed.",

that sounds like the cable hasn't engaged the speedo gear or head properly,, and is slipping.. - take the cable off ,, and pull the inner cable out an inch or so,, feed that into the square hole in speedo head,, then slip the outer jacket up to connect..

You may still have a tight bend in the cable somewhere..

The cable goes in the back of the speedo,, and spins a magnetic disc,, the magnetism lifts the needle off the pin,, the faster the disc spins, the higher the needle goes.. For the needle to waver,, the disc has to speed up and slow down,, now if there was a drag on the disc inside the speedo,, it would likely just slow down,, but it's possible,.. If the needle was sticking it would stay high at times,, or not return to zero.. The most likely place to cause a speeding and slowing of the disc,, is a cable binding somewhere,, getting bound, then springing free, thus the needle movement,, anyway,.. but make sure its properly engaged first..


hope it helps.. cheers..
 
Ill check for proper engagement. That would be a big pile of suck to fix...... The only thing that comes to mind is a shim of some type to go in the housing and lift the cable up out of the housing a bit?
 
All good suggestions. I had several cases of "bouncing needle". Once it was an improperly engaged cable (84 M-B 300D) and the other times wear in the speedo head - 65 Newport worn bore of spinning magnet, 82 Aries cracked plastic cap on magnet attachment. I fixed all, but the Newport I had to mail to a speedo shop to add a bushing to the bore.
 
Do not forget that there is the "other" end of the cable which would relate to the plastic speedo gear and teeth. However my bet would still be the speedometer needs rebuilt, but would still check the trans gear first. cheaper.
 
The noise is coming from the speedometer head bushing. You can try a light oil, not wd40. Remove the cable and lube the back of the interment cluster where the cable fits in to. Might work better if the cluster is removed from the car and face down. Don't use too much oil it will just make a mess. If it helps, your in luck, if not, it is time to have the speedometer rebuilt.
 
I remember reading somewhere that there is a cup that can be removed with a sponge or foam under it that needs to be oiled. The cup can be found on the top of the speedometer housing. I could be wrong on this though as I looked at mine and I did not see anything but an indentation.
 
I had one on a previous Demon that did the same thing. New speedo later and a new cable and it still jumped. (I never drove the speed limit anyhow) It turned out my speed odometer gear in the trans tail shaft was indexed wrong. The gear was actually toasted. I changed it and the housing and the jumping went away. Just saying that's what was my delima. It does not sound logical but it was the answer for me.
Good luck,
Joe
 
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