Speedometer needle bounce, 1968 GT350

[Corey Bowcutt]

My speedometer needle bounces when I am traveling below about 35MPH. It has about a 10 MPH bounce. Once over 35-40 MPH it smoothes right out. Is there a fix for that?
Corey

[silverton_ford]

Have you tried greasing the speedometer cable?    Use white lithium grease.

[Corey Bowcutt]

I have tried nothing so far.  So to grease the cable do you actually remove the inner cable from the outer sleeve and apply grease?

[Bob Gaines]

Have you tried greasing the speedometer cable?    Use white lithium grease.

Lithium grease can dry out. I have always been told by the old speedo restorers years ago to use a graphite lubricant. Not to say that you can't use Lithium grease but it is not the best thing you can use. 

[silverton_ford]

Have you tried greasing the speedometer cable?    Use white lithium grease.

Lithium grease can dry out. I have always been told by the old speedo restorers years ago to use a graphite lubricant. Not to say that you can't use Lithium grease but it is not the best thing you can use. 

Good recommendation on the graphite lubricant.   I have used white lithium grease in the past and haven't had troubles, but I have seen it dry out in other areas of use, so naturally it makes sense that it would dry out on the speedometer cable too.

I have tried nothing so far.  So to grease the cable do you actually remove the inner cable from the outer sleeve and apply grease?

Pull the speedometer cable off the back of the speedometer and then pull the cable out of the plastic sleeve and grease the entire cable.  Also add a little bit of grease on each end of the cable.   I don't think you need to pull the entire sleeve.   

I have done this on 70's Ford pickups and 60's Galaxies.  I would imagine a 68 Mustang would be the same process.

[Steve McDonald Formally known as Mcdonas]

Also make sure the cable is routed correctly and not bent or kinked.  I think the easy way to access it is to take the heater control loose and let it hang, stick your left hand into the opening and take the cable loose, pull it over to the heater control opening and use a pair of needle nose plyers to pull the cable out, grease it up and work it back into the sheath. Reassemble and try it

[papa scoops]

might need a speedo shock absorber. pookie got em. phred

[CharlesTurner]

An old-time mechanic I knew always used 3 in 1 oil.

[67350#1242]

Pretty sure transmission oil migrates in from the lower end but not enough to lubricate the whole cable.  I just remove inner and dip in motor oil.

[Don Johnston]

Lithium grease is not stable and will dry out to hard powder over time, accelerated by heat.  Graphite is the best for long term use that is why the cables have come with them originally for many decades.

[67350#1242]

The speedometer head itself can also be source of needle bounce and have seen damaged nylon gears in the odometer cause it - kind of a "once around" increase in friction leading to speed up, slow down in the movement.
Kurt.

[Corey Bowcutt]

All great advice thank you guys very much.

One more question, when I pull the cable out from the sleeve from the speedometer side do I have to remove the gear from the transmission first and disconnect the gear from the transmission side of the cable?

[67350#1242]

You can pull it out leaving trans. end intact.  When reinstalling just rotate a little till the square end slides into the driven gear on the other end.

[Corey Bowcutt]

Excellent!  Thank you.

[corbins]

Have you tried greasing the speedometer cable?    Use white lithium grease.

Lithium grease can dry out. I have always been told by the old speedo restorers years ago to use a graphite lubricant. Not to say that you can't use Lithium grease but it is not the best thing you can use.

+1