73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 1979C20 on December 11, 2010, 04:37:38 pm

Title: speedo cable
Post by: 1979C20 on December 11, 2010, 04:37:38 pm

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.

Title: Re: speedo cable
Post by: topp on December 11, 2010, 05:59:19 pm

Lube the cable....

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

Title: Re: speedo cable
Post by: 1979C20 on December 11, 2010, 06:14:37 pm

How do you lube the cable, kind sir?

Title: Re: speedo cable
Post by: topp on December 11, 2010, 06:40:15 pm

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....

Title: Re: speedo cable
Post by: 1979C20 on December 11, 2010, 07:07:37 pm

So, I have to pull my dash apart?

Title: Re: speedo cable
Post by: topp on December 11, 2010, 07:12:18 pm

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

Title: Re: speedo cable
Post by: captain carnage on December 11, 2010, 08:20:06 pm

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

Title: Re: speedo cable
Post by: 1979C20 on December 12, 2010, 12:01:03 am

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

Title: Re: speedo cable
Post by: 1979C20 on December 12, 2010, 01:03:52 am

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

Title: Re: speedo cable
Post by: Captkaos on December 12, 2010, 11:43:27 pm

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

Title: Re: speedo cable
Post by: 1979C20 on December 13, 2010, 01:03:33 am

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

Title: Re: speedo cable
Post by: Blue 82 on December 13, 2010, 03:40:44 pm

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.