speedo cable

[1979C20]

Since I got my truck running, the speedo has been starting to bounce more and more. And, its 5 mph slow. 50 on my speedo is actually 45. How can I calibrate it and how can I make it stop bouncing? 79 c20 350 sm456 4spd mantrans, 4.10 or 4.11 gears stock.

[topp]

Lube the cable....

If that doesn't work, replace the cable....

[1979C20]

How do you lube the cable, kind sir?

[topp]

Remove cable from back of speedo...
Spray lubricant (I use any kind of spray oil) down inside sheath of cable.
Reconnect....

Drive around the block, repeat...

Do it 3-4 times and then give it a decent run....

[1979C20]

So, I have to pull my dash apart?

[topp]

Remove Bezel....
Unbolt cluster.
Pull cluster forward while reaching behind speedo and unclip cable...

[captain carnage]

If your flexible you can reach in behind and do it with out taking anything apart.

[1979C20]

captain, I don't know about that. I'm a fat kid. Hahaha.

[1979C20]

Would 3in1 oil work? Or triflow? Or WD-40?

[Captkaos]

I use white lithium grease, WD-40 and 3-in-1 aint going to work.

[1979C20]

Alright. Ill grab a can of white lithium. Thanks.

[Blue 82]

I took an old speedo drive, the part that goes into the tranny,
and threaded a Zerk fitting into the end,
I remove the speedo cable from the tranny,
screw it into the moded speedo drive,
and hit it with a pump or two from the grease gun every other year. (light waterproof outboard motor grease)

If it's your first time you might need three or for pumps to keep it from jumping.