• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Jumping speedometer 72 Plymouth

Robert Schaad

Well-Known Member
Local time
12:49 PM
Joined
Dec 25, 2019
Messages
263
Reaction score
319
Location
89508
My speedometer started jumping. I know they do it after many years, since the bushing wears out. I pulled the speedometer cable out of the gauge and spread WD40 into the gauge, The place the speedometer cable pushes on the gauge. Then I put the cable back on. No more jumping. Just for every ones information.
 
The grease in the speedometer gear head also dries out over time. Have to pull the speedometer and work some lube in there but then should be good for another forty years.
 
Quite a common problem in 71-74 B bodys. I have never seen one that hasn't done it eventually.
 
just wondering, when jumping , did it make a clicking noise ?? mine does that, think i will give the wd-40 a try
 
The grease in the speedometer gear head also dries out over time. Have to pull the speedometer and work some lube in there but then should be good for another forty years.
Heck - only 40 years? I'll be around 105 then and don't want to be re-lubing the cable again at that age...
 
just wondering, when jumping , did it make a clicking noise ?? mine does that, think i will give the wd-40 a try
Yes, mine made a clicking noise as well just this last summer (for the very little I drove it). we got under there, removed the cable and sprayed it AND the speedometer where the cable goes. Clicking gone, but it still wobbles somewhat. As I mentioned, that is a 71-74 thing. My belief is it has something to do with the routing of the cable and the fact that it runs near the very hot exhaust. I've tried all sorts of different paths, it still has to cross the exhaust at some point.
 
Yes, mine made a clicking noise as well just this last summer (for the very little I drove it). we got under there, removed the cable and sprayed it AND the speedometer where the cable goes. Clicking gone, but it still wobbles somewhat. As I mentioned, that is a 71-74 thing. My belief is it has something to do with the routing of the cable and the fact that it runs near the very hot exhaust. I've tried all sorts of different paths, it still has to cross the exhaust at some point.
You could try to put a heat wrap on the cable where it is near the exhaust if you think this is causing the problem.
 
Thought of that and tried it, didn't help. However after saying that, it's possible the cable was already shot and it wouldn't have made a difference.
 
mine always " clicked " when the old cable was in, i installed a new cable now it jumps and clicks !
 
Probably need to lube the gears in the speedometer itself.
tea, gonna put my son under the dash( he is able to get in there better than me ) and have him spray inside the housing ( where the cable goes in ) with WD-40
 
tea, gonna put my son under the dash( he is able to get in there better than me ) and have him spray inside the housing ( where the cable goes in ) with WD-40
I was surprised that it worked, but it did.
 
The speedometer head has nylon gears and when the grease gets dried out and no longer lubes the gears then they start to bind which causes chatter and bouncing.
WD40 will probably fix it for a while but really needs something thicker to last.
 
The WD 40 will CLEAN IT, then you need to add some proper lubrication. Gears and cable included.
 
I pulled my cable out, spayed wd-40 into the speedo head, then sprayed some wd-40 silicone in, it is quieter now, but instead of jumping 15-20 mph, it wildly bounces for 0 to 130 until i get over 30 mph then it jumps 5-10 mph until around 50, then it smoothes out, thinking its in the speedo
 
I pulled my cable out, spayed wd-40 into the speedo head, then sprayed some wd-40 silicone in, it is quieter now, but instead of jumping 15-20 mph, it wildly bounces for 0 to 130 until i get over 30 mph then it jumps 5-10 mph until around 50, then it smoothes out, thinking its in the speedo
As you may know, when re-connecting the cable to the speedo gauge, gotta make for sure it is in all the way and not cocked - the collar threads back in straight and complete. Saying as this has been a hassle when reconnecting mine when unable to see the connection...just in case.
 
tea, gonna put my son under the dash( he is able to get in there better than me ) and have him spray inside the housing ( where the cable goes in ) with WD-40
Hi, I am 70 and did it myself. Spray around the place the speedometer cable goes on, not just in the hole the cable goes in. It has been working for months so far. Good luck.
 
Auto Transport Service
Back
Top