speedometer jumpy, bouncy

[use2teech]

Not sure if someone can offer any info other than what I've read in older posts. Have a 65 coronet 500 and the speedo needle bounces all over when driving, sometimes 10 mph jumps, sometimes 20 or 30. Does it all the time. I had an Imperial Services cable, bought it new when I built the car and it did it. I took the cluster out, cleaned everything and it still did it. Bought a used cluster from a member and it did the exact same thing, no change whatsoever. I ended up melting my cable this summer and bought a really nice cable from Kramer. Installed it and it's exactly the same. I've lubed both the old and the new cables, tried a light amount of a synthetic trans lube then a heavier amount of general purpose grease. Seems like I must be missing something as no matter what I've tried, nothing seems to make any change at all. It seems exactly the same each time.

 

[1967coronet]

lots of things can cause the jumping needle, to long of a cable, to heavy weight of grease, no grease, kink or dented cable housing, routing of the cable & housing, you said you had changed out the cluster, did you pull the speedo gear from the trans and check it over? they are plastic and do wear out . could be a bind down there in the trans were the gear fits through the bullet.
when you relube use a light coat of white lithium grease on a clean cable , make sure the inside of the cable housing is clean also.

 

[A383Wing]

sounds like the speedo head itself is bad, time for a rebuild or find one that works

 

[clazar]

Mine did that also. A new cable was all it needed.

Chuck

 

[bm02tj]

To tight of a bend can cause it
Check your routing and try to have longest bends possible

 

[MOPOWER871]

you would shake to if you were 50+ years to lol

 

[A383Wing]

Mine did that also. A new cable was all it needed.

Chuck

did you read his post? He has a new cable already

 

[use2teech]

Thanks for the responses. Like A383wing wrote, I am on my second new cable and second speedo head. It's done it every time pretty much the exact same as far as I can tell. Maybe the routing or the speedo gear as I haven't considered them. Thanks again.

Keith

 

[747mopar]

To much lash in the tranny gear could cause it but I'd definitely look at the routing.

 

[Tempest 455]

Same problem on my '65. Any issue just leaving it disconnected under the dash until I get a chance to fix it? I can ballpark my speed by RPM.

 

[miller]

Normal lube for a speedo cable is dry graphite powder.

 

[djais1801]

idk...the last 2 mopars I had did it...

 

[Darter6]

Where the cable slides into the back of the cluster you will find a brass bushing.Check to see if it clean/dry. Pack the bushing with Vaseline petrolatum jelly with your finger. I had a speedo company tell me that,,Bull sh!t I thought,, Dang it worked.Just a thought.

 

[mopar73dge]

well I used a mopar speedometer cable lube, not lithium, I purchased brand new mopar cable it was dry I had to add almost a whole tube of Mopar speedo lube, the first time I installed the cable the needle was jumping, this right after the speedo was rebuilt! you never know what to expect. good thing I checked the cable. works like new now. The orginal speedometer cable on my car was made by Stewart Warner it was imprinted on the casing!