speedometer jumping

[74roadrunner440]

i just put in 150 speedo in my 73 rr and repaced with white faces but now the spedo jumps up n down when i drive i only whent from shop to garage but i know when i put spedo cable in it was a pain to get in all the way what do u guys think could be the prob i did paint the needle and when i had it out it seemd ok is the peedo shot or did somthing hapen to cable jw what would cause this b4 i rip the guages back out again thanks again pat

 

[egrand1508]

Usually that's a sign the cable is going bad or needs lubed. The inner spring is binding somewhere along the cable.

 

[74roadrunner440]

it worked fine b4 i took the guages out and replaced speedo with 150mph speedo and put white faces on

 

[YY1]

Probly got a kink in the cable, or made it rub someplace that wasn't lubed good.

I'd lube it.

I use white lithium grease and pull the cable all the way out of the sheathing after disconnecting both ends.

Then I take the white lithium and put several dollops along the cable- rubbing it in with my "other" hand.

If your good at manual dexterity, you can do it while you feed it back into the sheath.

 

[74roadrunner440]

ya im verry mechanicaly inclined i thought it was the cable but wasnt sure since i put in a difrent spedo just want somone elses opinion and thanks alot guys

 

[YY1]

Could be the speedo. I've seen that too. At least you still have the old one, right?

 

[74roadrunner440]

old 1 is junk

 

[Bruzilla]

I have the exact same problem with my car. Don't bother replacing the speedo cable. If it worked fine with the old speedo it's working fine now. The problem is with the speedo you put in. I had a 120 unit in my original cluster and it worked fine, then I replaced the cluster with a 150 unit and the needle's dancing around like mad. I replaced the speedo cable, and that's how I found out that's a waste of time and money.

From what I've been told, the problem is the speedo needs to be lubricated. I've thought about pulling the cable and shooting some WD40 into the back of the speedo, but I haven't tried it yet.

 

[74roadrunner440]

i replaced cable got a little better bot not like b4 either i need a new speedo or try n figure out y its dancing mabe ill try lube girls say lube is good rofl thanks for your help

 

[themechanic]

Mine jumps but is fairly accurate. So, I emailed Gary the Tachman who said, "the frame and magnet in the speedo needs replaced". He wants $195. Sounds a little steep. What think the rest of you?

 

[UKPlymouth]

Mines a jumper too. I ruled out the cable by detaching it and then cable tying to the bottom of the heater control unit. As you drive along you can see the cable turning evenly.
Does anyone make new speedo units?
Autometer do have a. 5" mechanical unit out there for about $140 that takes a cable drive.

 

[fla 66 cuda]

Mine jumps in my cuda i replaced the cable and cable houseing it still bounced i'm also told the magnetic parts have lost their magnetic powers.

 

[Doubleclutch]

I had one in a 57 Chevy that jumped. One day while cruisin a about 30--it hung. I heard a scratching and the needle went to zero. It scratched and clawed for a couple of seconds and then cut loose --I registered over a 100 before the kink unwound. Then back to 30 and all was well. Cable finally quit some time later.

 

[BeastlyBirdie]

If the Speedo sat for awhile, it could be gummy. Ive used electronics cleaner as it doesn't leave much residue. Just blast it in the hole. Lube the cable while you are at it. Graphite mixed with alcohol has worked for me.