65 speedometer fluctuates

[Bob611]

The speedometer in my car bounces erratically after 45/50 mph. The bounce only gets wider the faster I go. Cable or is this a problem with the speedometer itself?

 

[OhioTbird]

I recall my dad having to occasionally grease the cable. Think he used a graphite grease.
Wasn't a TBird but definitely a Ford. The only cars he ever bought.

 

[Frosty]

One of my 65's did the same. Cured it by taking the speedo out and apart then cleaning the revolving drun and all other parts which had dust on them. Put it back together and it worked fine.

 

[57tbird57]

The speedometer in my car bounces erratically after 45/50 mph. The bounce only gets wider the faster I go. Cable or is this a problem with the speedometer itself?

sounds like a cable problem. most likely dried out grease. could be a wore out plastic gear where cable goes into the tranny.

 

[Tbird Rich]

My 65 does similar. After I hit 55 MPH the speedo zomes up to 90..I have not tried to fix and hoping it wont get worse..

 

[Bob611]

Thanks for the answers. I think I'll start simple and check cable. Hate to tear into dash.

 

[jj_sharp]

My wife's does what
Tbird Rich
does (hits a certain speed then it wants to go full scale in a hurry).
.j

 

[64ZCODE]

Yes bouncing speedo first to check is lubing the cable with graphite lubricant. No comment on wife's tendency to go from naught to full on

 

[doug7740]

I know that you have a 1965 Thunderbird, but attached is an article I wrote on speedometer lubrication for a 1955 to 1957 Thunderbird that might help.

doug7740
1955 Thunderbird Blue