Speedometer jumping around after hitting the brakes

[Michael_]

My speedometer functions normally most of the time.
But when i hit the brakes the needle is going up and down for a while until going back to normal.

I already found this thread with lots of good suggestions

1970 Roadrunner Speedometer Jumping Around

If my speedometer needle is jumping around when I drive is that the cable or the speedometer? It is a new replacement cable on it right now.

www.forbbodiesonly.com

But i was wondering if you guys already know exactly what this is given the behavior described above?

 

[kiwigtx]

My speedometer functions normally most of the time.
But when i hit the brakes the needle is going up and down for a while until going back to normal.

I already found this thread with lots of good suggestions

http://[URL]https://www.forbbodieso...roadrunner-speedometer-jumping-around.178759/

[/URL]

But i was wondering if you guys already know exactly what this is given the behavior described above?

Make sure that your brake pedal 'arm' is not interfering with the speedometer cable under the dash - the pedal may be pushing the cable housing around when you apply the brakes.

This is assuming you have a cable driven speedometer.

If you have an electronic speedometer with a Hall effect drive - then you need to run a screened cable from the speedometer sender unit to the actual speedometer gauge.

 

[kiwigtx]

 

[Michael_]

Make sure that your brake pedal 'arm' is not interfering with the speedometer cable under the dash - the pedal may be pushing the cable housing around when you apply the brakes.

That is a great idea.
Yes it's the original cable driven speedometer.

 

[Michael_]

Make sure that your brake pedal 'arm' is not interfering with the speedometer cable under the dash - the pedal may be pushing the cable housing around when you apply the brakes.

I checked and this isn't the case.
The cable also seems to be correctly seated in the speedometer.

I will check the transmission side next but it almost looks like it's the speedometer itself unfortunately.