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I have a speedometer needle bounce that occurs only above 40 mph. (bounces back and forth between 40 to 60 and increases with speed 40 to 80)I have removed and cleaned/lubricated the cable and have little change in bounce. The cable does not appear to be kinked or bent.
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Speedometer bounce.
- Thread starter DEVOREBN2
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It could be the cable or the speedo. The cheaper test is a new cable. Even though you have lubed the current cable, it could be snagging on something near the speedo end of the cable. The newer cables available from places like Moss are a little thin and are prone to the bouncing needle problem after a while. I had one made by the local British speedo guys which is thicker and can take the bend around the trans and tunnel wiothout bouncing while the trip odometer is ticking over.
With that said, make sure your speedo is not making any unusual sounds. You don't want it destroying itself. It too could be binding up internally and causing the problem. If after replacing the cable you still have the problem, then it's time to send the speedo into the shop for an overhaul and calibration.
Mark
With that said, make sure your speedo is not making any unusual sounds. You don't want it destroying itself. It too could be binding up internally and causing the problem. If after replacing the cable you still have the problem, then it's time to send the speedo into the shop for an overhaul and calibration.
Mark
Online
I had a small amout of bounce in my needle at 60 and above. After I put the 5 speed tranny in the bounce has gone away completely. I would also think the elbow drive off the tranny is a possible problem.
healeynut
Jedi Knight
Offline
Usually when a cable wears, it gets worn by getting longer in length. when the Speedo cable gets a bit long from wear, it puts pressure on the speedo's magnet wheel, which then interferes with the needle pickup, causing bounce.
Try putting a little washer that will push the speedo cable housing out a bit, in effect lengthening the housing so that the cable isn't too long. Also, there is a little copper washer in the angle drive that is often missing - if you put on in it may help the symptoms.
Finally, if you don't want to do any of this, just have a new cable made at a speedo shop that's about 1/8" shorter - that should do the trick.
Good Luck!
Try putting a little washer that will push the speedo cable housing out a bit, in effect lengthening the housing so that the cable isn't too long. Also, there is a little copper washer in the angle drive that is often missing - if you put on in it may help the symptoms.
Finally, if you don't want to do any of this, just have a new cable made at a speedo shop that's about 1/8" shorter - that should do the trick.
Good Luck!
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The speedo cable consists of two parts, the "housing" and the "cable". Most of the time the bounce is due to the cable actually getting oval shaped. The cable is cheaper than buying the whole unit and you should be able to get one "cut to size" at a shop that does speedo work. Do not overlook truck repair places, because a lot of trucks still on the road use the old system.DEVOREBN2 said:
Patrick
If the needle is bouncing above and below the actual speed, then the cable is wrapping up. This is usually caused by the cable snagging at the end closer to the speedo, or inside of the speedo. If the speedo is not making unusual noises, then it is probably your cable.
Mark
Mark
DanNagy
Jedi Trainee
Offline
I had this exact problem in my TR6, and after having 4 different cables installed and the connections checked at either end, I gave up. However, I now have a new mechanic who told me that a gear inside of the speedometer was bad. He sent it out to be rebuilt and I hope that this solves the problem. If you decide you would like to rebuild your speedometer, I could find out where he sent it and let you know. -d
This thread is already a bit old, but want to add my comments:
I have the same problem - even after a complete rebuild of the speedometer. When you look into the details of the odomoter every few turns the magnetic wheel shifts the gear of the odomoter forward. This takes a bit of the momentum. When there is play in the whole thing you will see the bouncing speed. Don't know whether you really get it completely smooth when everything is like new. The way on how it works should give you always a bit of bounce. Good luck
Alex
I have the same problem - even after a complete rebuild of the speedometer. When you look into the details of the odomoter every few turns the magnetic wheel shifts the gear of the odomoter forward. This takes a bit of the momentum. When there is play in the whole thing you will see the bouncing speed. Don't know whether you really get it completely smooth when everything is like new. The way on how it works should give you always a bit of bounce. Good luck
Alex
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If the bounce is caused by cable windup, you should only see a bounce about every 1/10 mile, not continuously.
A possible & common cause is an inner cable at the speedometer end that is slightly too long. The cable end should only project about 1/4" from the housing face. Any longer can cause internal binding of the speedometer head. It's easy to trim a bit from the end of this inner cable. Even new replacement cables can have this problem.
Take care that the cable where it enters the head is perfectly in line with the head. The main speedometer housing is quite thin & flexible. Very easy for a mis-aligned cable to warp the housing & the alignment of internal parts.
D
A possible & common cause is an inner cable at the speedometer end that is slightly too long. The cable end should only project about 1/4" from the housing face. Any longer can cause internal binding of the speedometer head. It's easy to trim a bit from the end of this inner cable. Even new replacement cables can have this problem.
Take care that the cable where it enters the head is perfectly in line with the head. The main speedometer housing is quite thin & flexible. Very easy for a mis-aligned cable to warp the housing & the alignment of internal parts.
D