My speedometer quit working on my '83 F100, 300 6 cyl., 3 speed. It doesn't move at all.

I removed the cable from the transmission thinking the teeth on the nylon gear might be wore bad. Nope, not that.

And when I try to spin the cable with my fingers, it is hard to turn or spin. Like it's in a bind and springs backwards a bit after twisting it. I hooked my drill (Only one direction) to it and it would spin around (Clockwise) okay but the speedometer wouldn't move any.

I could get my hand on the cable connection behind the dashboard speedometer itself...and can slide the end cap connection back and forward a good bit but couldn't twist it. Wonder if the cable attaches to the speedo by a twisting screw on/off action or something else?

And shouldn't I be able to spin the cable gear end at the transmission rather easily? If I had gotten it disconnected from the dash I would have seen if it then spun any easier. Does the "Binding" of it indicate my actual speedometer is frozen or locked up and might be at fault instead of the cable?

 

It's most likely the cable is broke inside the cable housing, or the gear at the transmission is stripped, or the white plastic drive "thing" at the end of the spedometer cable at the head is sheared off or stripped.

With the instrument cluster ready to be removed...

On the back of the speedometer cable housing at the back of the speedometer head. There is a white plastic catch. Press down on the flat portion with your thumb as you pull back the housing from the speedometer head.


On the gear driven end, there is a little clip that holds the speedometer gear on the cable. Remove the speedometer gear.

Inside the cab you will see a white plastic "thing" inside the cable housing. It has four sides to it and acts like a gear. Is it stripped, or is the white plastic "thing" end of the cable snapped off inside the speedometer head?

Pull the cable out of the housing through the cab end. With it completely out check for signs of damage etc. Replace if nessecery.

Use plenty of Ford's Speedometer cable lubricant or white lithium grease will work, to grease up the cable. The cable should turn pretty free inside the housing. Should be able to turn it with your fingers etc..

Remember, the cable can and must, turn both ways. Foward and reverse. If you had your drill turning the wrong way, it may have been like the truck going and driving in reverse, like when you back up etc... The speedometer does not work in reverse by design. etc...
Hope this helps,

 

Yeah, it helps, thanks!

My drill doesn't have a "Reverse" switch on it. I would have like to spun it counter-clockwise and seen if it moved...but couldn't.

What concerns me is the cable doesn't turn freely. Seems that even with it still attached on the dash end, it should...and did a month or so ago when I replaced a clutch release bearing, I think it did.

Maybe a cable can kink when it breaks and not turn easily. I hope this is it and not a broken speedometer in the cluster. But it looks like I'll have to pull the instrument panel to see any plastic catch to take it loose as mentioned. UGHHH!

 

It's not a hard job. Dont worry about it.

 

The Cable can fray. The cable is made up of smaller "wire strands" simular to what the big cables are on suspension bridges.

Simular to the throttle cable.

 

I got it fixed today, it was a broken cable that was frayed so bad it was hard to pull out of the casing. And it wasn't that hard of a job as mentioned. Just take some screws loose as you advance with removing the dash panel layers. Not much to it. Only thing is my speedometer is bouncy now...but I've only driven it 1 mile to test if it worked or not. I'm thinking it might work itself out and become steady after some miles. Such a simple job, I can't see how I may have put something together wrong.

And cost...not bad at all. At our local American Auto Supply store I got the "Universal" cable where you hammer the square end on using a little tool that comes with it for $5.30. Auto Zone wanted $9.97...so much for them being cheaper on parts.

Thanks for the info guys!

 

Did you lubricate the new cable? You can't have too much lube on the cable. Just don't get it into the speedo head itself.

Ford has special Speedometer cable lubricant.

You can also use white lithium grease, but the "speedo cable lube" is better IMO.



You might need a new "casing" if the old frayed cable wore a hole in it. Just a thought.

Hope this helps.

 

I hate to admit this, but I was almost back home when I realized I forgot the lube. I found some bulbs burnt out and missing in the dash when I took the panels off, and getting them kinda distracted me a bit. I forgot to get the lube. I shot the cable full of WD40, which may not have been a good idea. But If the needle doesn't stop bouncing soon, I'll just get the cable/casing/Lube and do it over. But do it right this time.

 

Yeah, WD40 isn't good enough. Infact I wouldn't use WD40 on anything except for water displacement, or rust prevention. It can attract dirt.


If you didn't lube it proper, then that's the bouncing problem.

If you don't get it corrected the new cable could break also.

I would try just lubing the cable really good first. The casing may be in good shape.


Hope this helps