Speedometer needs rebuild or it's the cable?

[rzorrilla2348]

Recently, my speedometer gauge begins to spin out of control after 20-25 MPH. It comes and goes though. I just checked the gear at my transfer case and it looks ok (plus it's relatively new as I replaced it six mos ago.) But I just ordered a new cable ...however any opinions, could it be the original gauge instead? Here's a vid

76' 351W 3" lift with 35" tires

 

[Speedrdr]

My guess is the cable end at the speedometer head is worn and allowing the needle bounce. At least, that was the way my speedometer cable acted in a 76 celica gt just before the cable broke.
Randy

 

[jckkys]

I've seen this on several speedometers and fixed it by lubing the cable with graphite cable lube, available at any chain type parts store. Some times the bearing in the speedometer head needs lube too. I used CLP for that.

 

[MikeCon]

My cable on my 73 broke.replaced it and it jumped all over the dial. PULLED internal cable out at firewall and lubed with graphite lube..still jumped a little until lubed worked in and is working fine..I would recommend replacing cable since they are cheap.

 

[rzorrilla2348]

update: replaced the cable and kept the same gearing. At first it didn't appear to fix things, but after some driving, it began to settle a bit. However, I used a little graphite lube by the speedometer... now, it's really steady...better than before. thanks again.

 

[dkmorganjr]

Sorry to ask a dumb newbie question, but I am having a similar issue with my '77. I have changed out some of the lights on my cluster but did it all while it was in the dash.

Do you have to take the whole dash apart to work on the speedometer or replace the cable, or is this something you can do without taking the whole dash apart? I am afraid if I take it apart, I won't ever get it back together.

Even though I bought new lights for the cluster and a new instrument voltage regulator, I am thinking about just buying a new instrument cluster; however, again I am worried I will pull everything off and not hook it back up correctly.

Any guidance or suggestions are greatly appreciated. You guys are awesome.

 

[rzorrilla2348]

@dkmorganjr ... I did not remove my speedometer cluster in my repair... I simply reached under the dash and near the center of the cluster, you'll find the connection to where you screw the cable onto... hard to miss. The nut of my prior cable was even removed by hand. Pretty straight-forward fix but avoid severe benting or kinking the cable as the rod inside needs to spin freely.