Speedometer evaluation?

[Mattax]

What else can I check on my own?
Or is this enough to determine course of action?

67 Barracuda 120 mph Speedometer with trip odo.

Here's are the symptoms and what I've checked so far:

This speedometer occassionally was bouncing hard (jittery). Sometimes its completely fine. I have removed, cleaned and relubed the cable a few times. Coming back from central Pa this fall,going approx 50 mph it was making a little growl every 15 or 20 seconds. Last week had it out - nothing audible at all. ( I did try @pishta idea of using a siringeto place little drop of oil in the brass cup. I'm still not sure if there is a pinhole at the bottom to actually let any oil through.) I might have just straightened/tightened the cable housing enough to resolve the noise.

Since the instrument panel had to come out anyway, it was time to look at this thing.

First test was this.

in a leaned back position, resting on the input shaft. Wear in the instrument causes the magnets to draw the needle away from '0'. If the needle lifts to more than 5 mph, continue shopping for better.
When new, bias force on the input shaft wouldn't move the needle at all.

There is a tiny amount of for aft movement (about 1/64 or even less).
No movement of the needle

Visually, other than dust and dirt, I don't see any obvious wear in the gearing.
Evaluating the photos it does look like the shell may be getting kissed. Yes?

 

[Mike69cuda]

The cable housing can still be bad. Mine was jumping even after I lubed it. I replaced the cable and it got a lot better. Still jumped some.

When I had it out of the car I hooked a dremel tool cable up to it and put a drill on the other end. It ran the speedo nicely and I picked the best of the two speedos I tested.

 

[Mattax]

The cable housing can still be bad. Mine was jumping even after I lubed it. I replaced the cable and it got a lot better. Still jumped some.

When I had it out of the car I hooked a dremel tool cable up to it and put a drill on the other end. It ran the speedo nicely and I picked the best of the two speedos I tested.

I'm afraid that may be true. I'll have to see if anyone can make '67 cable housing or if its a best of used type of deal. I definately want to keep the trip odo.

 

[Mike69cuda]

I have a lightly used one you can have if you want it. I had had a lot of trouble finding one & made this one with some universal parts. It worked good until I put in a cruise control in and couldn’t use it then. It has the plastic speedo connector and the one inch nut for the trans.

 

[Mattax]

I have a lightly used one you can have if you want it. I had had a lot of trouble finding one & made this one with some universal parts. It worked good until I put in a cruise control in and couldn’t use it then. It has the plastic speedo connector and the one inch nut for the trans.

Thanks for offer. I think it must have the threaded connector if I'm to keep theis speedometer. Maybe its not that hard to get made. I noticed I had a lcable housing from my 727 equiped Jeep that has both ends threaded.

 

[Mike69cuda]

Oops, should have noticed that from your pics. I think you can buy that one at Oreilly’s. It has been awhile, but I looked through thier speedo vendor catalog & it seem that was one you could get.

 

[RedFish]

What I know....
Speedometer cables can work fine in warm weather and raise hell in the cold.
99% of speedometer pictures show the head on a table and leaning on its input shaft. When they were new this didn't distort the magnetic field, needle wouldn't move at all. Some are so worn that the needle has climbed to 7 mph in the picture. In that case,, If one part isn't already touching the other, its going to soon enough.
The odometer is direct driven. In the basic odometer, the little planetary gears between the digit wheels are brass, but in the added trip clock, they are plastic. The tenths wheel carries all of them and they put it over on the trip clock. Engineering failed right there? No. it was designed to last 10 years or more. The better question is how many times has the trip clock been hand wound back to zero during 50 years.
I don't see the needle lift in your picture. you might check for it. If a new cable doesn't cure it, disengage the odometer and see if the intermittent problem goes away.
I have 2 67 model rally speedometers here just like yours with tenths wheel worn completely out. Both need only that 1 part that I don't have a source for.
I went ahead and bought a good used 68 speedometer without the trip clock. It will go in my 67 with a new cable when needed. Good luck with yours

 

[toolmanmike]

The cable housing can still be bad. Mine was jumping even after I lubed it. I replaced the cable and it got a lot better. Still jumped some.

When I had it out of the car I hooked a dremel tool cable up to it and put a drill on the other end. It ran the speedo nicely and I picked the best of the two speedos I tested.

Same with my 66. I had lubed and cleaned the speedo and cable a couple times. I went to NAPA and got a new cable assm. and it took care of the problems. (jumping, jittery needle, noise)

 

[Mattax]

I don't see the needle lift in your picture. you might check for it. If a new cable doesn't cure it, disengage the odometer and see if the intermittent problem goes away.

Redfish,
No lifting of the needle at all. Just slight in-out play of the input - maybe 1/64 more like 1/100th.

My concern is this wear mark. Is the support shared between the cable and internal bushings so cable alignment alone could cause this?

 

[pishta]

...
I have 2 67 model rally speedometers here just like yours with tenths wheel worn completely out. Both need only that 1 part that I don't have a source for. ...

I had Sammy (@ MuuMuu101) make me a tiny gear on his 3D printer, maybe he could make you a 10ths gear? would have to send him a CAD file of it, but there are plenty of gears over at tinkercad.com. just look at other projects, find one that has the same tooth count and scale it to what yours would have been.

 

[toolmanmike]

Redfish,
No lifting of the needle at all. Just slight in-out play of the input - maybe 1/64 more like 1/100th.

My concern is this wear mark. Is the support shared between the cable and internal bushings so cable alignment alone could cause this?
View attachment 1715476694

Just curious, is the drum rubbing all the way around or just on one side?

 

[Mattax]

Just curious, is the drum rubbing all the way around or just on one side?

Just one section.

 

[toolmanmike]

Does the drum seem loose? It might need a new bushing. Dang, There was an old guy in a town nearby that repaired speedos and gauges. Ted's Auto Electric. The guy was a whizz at that stuff. He passed away years ago. RIP.

 

[RedFish]

The brass collar and a steel trust washer was pushed on to flush. A little bit of lengthwise movement is normal. Grease/crud builds up in that square port and maybe it could push the spindle lengthwise. Thats doubtful. You should clean it well before inserting a new cable. If the spindle doesn't defect and move the needle, try to wiggle the drum. It looks cocked in the last pic. Its mounted between to tiny bronze bushings. I've seen those severely worn only once and shared pictures of them here years ago. That was a earlier model speedometer with 100K+ miles on it. The shaft broke right at the front bushing.
Lets hope the marking you see on the drum is only the factories balancing scar.

 

[RedFish]

I had Sammy (@ MuuMuu101) make me a tiny gear on his 3D printer, maybe he could make you a 10ths gear? would have to send him a CAD file of it, but there are plenty of gears over at tinkercad.com. just look at other projects, find one that has the same tooth count and scale it to what yours would have been.

I guess I wasn't clear. I have plenty of extra gears, etc... its the inside of that tenths wheel that finally fails and of course its different from all others.

 

[Mattax]

If the spindle doesn't defect and move the needle, try to wiggle the drum. It looks cocked in the last pic.

Not sure I fully follow. I can clean the port and take existing cable out of the housing and use that to see if it moves the spindle?
Do understand the part names correctly? (Thrust washer we can't see)

 

[Mattax]

and then these are the drum support bushings?

 

[RedFish]

Almost correct. The needle is on the same shaft as the drum/stator whatever its correctly called. the lower/rear bushing is in the middle of the magnet part. Your arrow points at a fastening center hub. The shaft passes through that.
Please know, I've been into only 10 or so examples. I haven't seen all the faults. I assume what I have seen is most typical. Foremost is the cast metal bore with steel input shaft running in it. Cable alignment is a huge wear factor here. The 68 and up plastic sleeve type cable attachment is the better design. Our collector nut does little to align the cable and sheathe.
Speaking of can't see... The trust washer(s) at bronze bushings are phenolic and very tiny.
Do you see a thrust washer here? Does all this look well centered?

 

[Mattax]

Thank you. I'll have to look tomorrow to see if its there and how well centered.

 

[Mike69cuda]

Cut an old cable down and run the speedo with a drill. That should give you a lot of info since it is out in the open where you can watch.

 

[RedFish]

If you're going to run it, color that scaring with a sharpie.

 

[Mattax]

Great idea. I have some 'prussian blue' but that might be too heavy and messy.
First I have to dig around for the leftover speedometer cables from the Wagoneer. I might have tossed them - can't remember.

 

[RedFish]

About oiling the shaft. I use a razor blade to get under edge of that plug, work around and pick it out. I use a needle to pick the wick from the hole. I can wash the wick and bore too with brake clean, allow to dry and relube with 3in1 oil. The natural table lay of the instrument allows excess oil to drain at rear. Is it necessary? I don't know. I know all this disappeared in later examples. bump in casting remains. the hole, wick, brass plug,,, gone.

 

[Mattax]

Please know, I've been into only 10 or so examples

That's 10 more than most us have taken apart! All of your insight is really appreciated!

Speaking of can't see... The trust washer(s) at bronze bushings are phenolic and very tiny.
Do you see a thrust washer here? Does all this look well centered?

With glasses a magnifying glass, the answer is yes. I tried a close up photo, lets see how it came out.
Meh

try to wiggle the drum.

All too easily.
The input spindle has just a little side play at the drum. Using a dial indicator its about 0.004"
But the drum has around 0.020"
Think this needs to go to watchmaker for repair...

 

[RedFish]

The bushings wear egg shaped. I suppose you rotated things to measure movement. Speedometer repair aint cheap. Those little bushings are made of a naval bronze. I couldn't afford to have them made in small quantities and we had the raw material left over from a previous job.
My money would be spent on a 68 up without the trip clock and a new cable with the improved attach design but... these cars aren't daily drivers anymore. A lot of years to wear out any speedometer. Good luck with it.