Jumpy Speedo - The 1947 - Present Chevrolet & GMC Truck Message Board Network

squeekyM · 10-24-2005, 01:19 AM

Hi Everyone,

I was wondering if anyone has dealt with a jumpy speedo before? Between the speeds of 40- 70 mph, the speedo jumps back and forth, and sometimes seems to skip (like when traveling at atleast 65-70mph it will read someone around 40-55). Any ideas of why this could be caused?? Thanks.

- Jerry

sdkid · 10-24-2005, 01:34 AM

Unhook the cable from the back of the cluster. Pull the cable from inside the casing. clean it and coat it with some white lithium grease, and reassemble. See if that helps. You don't want any of the grease in the back of the speedo head. If this does not help, it may be internal to the speedo head itself.

Americanrider · 10-24-2005, 03:00 AM

Lube it or lose it as they say....
The jumping needle is caused by the cable binding up inside the cable casing, once it frees itself from the bind it will spin faster to unwind the twist put in, then bind up again. Graphite lube works better than lithium and will not congeal with age or cold weather. You can even use Graphite lube in your door key locks to keep them loose during winter since it will never freeze up.

Brad · 10-24-2005, 03:18 AM

Also look for any kinks as this will cause the same problem as Americanrider described it.

cdowns · 10-24-2005, 09:54 AM

i prefer a graphite based speedometer cable lube made expressly for this purpose it actually polishes the inside of the cable housing preventing future problems like the dried up caked grease will cause// available at most autoparts stores for a couple of dollars

squeekyM · 10-24-2005, 11:24 AM

Great advice everyone. I will give it a shot, thanks.

Austin C10 · 12-19-2005, 11:03 AM

Quote:

Originally Posted by cdowns

i prefer a graphite based speedometer cable lube made expressly for this purpose it actually polishes the inside of the cable housing preventing future problems like the dried up caked grease will cause// available at most autoparts stores for a couple of dollars

My cable was noisy and the needle was also jumping. I cleaned it with WD-40 and then sprayed graphite in both ends of the housing. I replaced the cable, and its still jumping. Any other suggestions? Should I spray more graphite in the housing?

cdowns · 12-19-2005, 11:32 AM

Quote:

Originally Posted by Austin C10

My cable was noisy and the needle was also jumping. I cleaned it with WD-40 and then sprayed graphite in both ends of the housing. I replaced the cable, and its still jumping. Any other suggestions? Should I spray more graphite in the housing?

it wouln't hurt also with the cable iboth of wout check it with your fingers to see if there's a bump in it from a broken wire strand or go down the housing assy and see if there's a kink or a crushed flat spot in it both of which are difficult but not impossible to straighten out

jimfulco · 12-20-2005, 03:50 AM

A binding cable will make it wave back and forth in a regular fashion, with the actual speed being about in the center of the range of motion.

Sounds like you're having the same problem I have with my '79, with the speedo reading steady (or fairly steady), but 10 or 20MPH above or below the actual speed. I'm still looking for a cure, if there is one.

10-24-2005, 01:19 AM	#1
squeekyM Registered User Join Date: Jun 2005 Location: California Posts: 51	Jumpy Speedo Hi Everyone, I was wondering if anyone has dealt with a jumpy speedo before? Between the speeds of 40- 70 mph, the speedo jumps back and forth, and sometimes seems to skip (like when traveling at atleast 65-70mph it will read someone around 40-55). Any ideas of why this could be caused?? Thanks. - Jerry

10-24-2005, 01:34 AM	#2
sdkid Registered User Join Date: Sep 2004 Location: Pierre SD Posts: 1,533	Re: Jumpy Speedo Unhook the cable from the back of the cluster. Pull the cable from inside the casing. clean it and coat it with some white lithium grease, and reassemble. See if that helps. You don't want any of the grease in the back of the speedo head. If this does not help, it may be internal to the speedo head itself. __________________ I think the world needs a drink... Help somebody...If you can....VanZant We're not wrong, we're not sorry, and its probably gonna happen again. That's the truth about men. Tracy Byrd Member# 13924 '70 c10, 350/350 '68 c10 250/4spd '68 c10 no eng/trans fac ps/pb/ac/at (future father/sons project) '48 Chevy Loadmaster

10-24-2005, 03:00 AM	#3
Americanrider Registered User Join Date: Dec 2004 Location: NW, WA. Posts: 1,421	Re: Jumpy Speedo Lube it or lose it as they say.... The jumping needle is caused by the cable binding up inside the cable casing, once it frees itself from the bind it will spin faster to unwind the twist put in, then bind up again. Graphite lube works better than lithium and will not congeal with age or cold weather. You can even use Graphite lube in your door key locks to keep them loose during winter since it will never freeze up. Last edited by Americanrider; 12-20-2005 at 04:45 AM.

10-24-2005, 03:18 AM	#4
Brad Out of the carpool lane. Join Date: Jan 2000 Location: Clark Co, WA Posts: 5,673	Re: Jumpy Speedo Also look for any kinks as this will cause the same problem as Americanrider described it. __________________ 1968 C-10 SWB, 5.7 Vortec/700R4/3.73 posi, Torch Red 1968 Camaro, 250/Powerglide, all original (No, I'm not gonna drop a 350 in it!...Jeez!) 2000 Honda VFR in the faster yellow! 2008 Husqvarna TE-610 1967 C-10 SWB 'Six Appeal'-Gone but not forgotten...

10-24-2005, 09:54 AM	#5
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Jumpy Speedo i prefer a graphite based speedometer cable lube made expressly for this purpose it actually polishes the inside of the cable housing preventing future problems like the dried up caked grease will cause// available at most autoparts stores for a couple of dollars __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

10-24-2005, 11:24 AM	#6
squeekyM Registered User Join Date: Jun 2005 Location: California Posts: 51	Re: Jumpy Speedo Great advice everyone. I will give it a shot, thanks.

12-20-2005, 03:50 AM	#9
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	Re: Jumpy Speedo A binding cable will make it wave back and forth in a regular fashion, with the actual speed being about in the center of the range of motion. Sounds like you're having the same problem I have with my '79, with the speedo reading steady (or fairly steady), but 10 or 20MPH above or below the actual speed. I'm still looking for a cure, if there is one.



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