Speedometer diagnosis

[Archrms]

Went out for a ride the other day and noticed the speedometer was not working. Seemed to be working fine last time I drove it. No warning, noises, jumping needle - just stopped working. How do I tell if the problem is in the speedometer, the cable, or something else?

[mpanten]

If its a smiths, check on the back of the speedo, mine just screws in there and has come loose, also check on the transmission to see if its still connected. Other than that im not sure what the issue could be unless it just broke.

[Kramer]

I have gone through this a few times....before I even pull the speedo out, I would disconnect the cable from the tranny and speedo and see if you can spin by hand or with a drill. If you can't it is most likely a broken cable (fairly common I afraid).

[Sailfish]

I assume you have a Smith's speedometer---------if not, disregard this note. I've experienced the same issue and found it to be the reverser on the back of the speedometer. A piece of the reverser worked itself loose by backing out of its normal position. I ordered a replacement reverser and it appears to be a more robust design (it is "staked" in place preventing movement). I installed the new reverser and everything works great. I ordered the replacement from Nisongers and it cost around $90.

[RAO-3]

If you do have a reverser, be sure to check that it functions properly. The parts are press-fit and mine loosened up so had to replace it. Then make sure the new one spins freely before installing.

[Archrms]

I think I found the culprit. I pulled the reverser off the back of the speedo. The reverser has a plastic insert that transmits the rotation from the reverser to the speedo - and it appears to have twisted and snapped off, with part of it still in the speedo. I need to find something small enough to fit into the rear of the speedo and try to extract the plastic insert that broke off. Then I can determine if the speedo rotates or is locked up (which would explain why the plastic insert twisted and broke).

[Archrms]

I spoke with Nisonger regarding repair of the Speedo. They quoted $175 to rebuild the unit, and $350 for a new one. They also said that the it was not worth rebuilding the reverser (if necessary), and recommended just buying a new one. Has anyone had experience with Nisonger regarding repair of their gauges?

[mpanten]

I will be sending one back shortly, they have a 2 year replacement gaurantee, how long have you had it?

[Archrms]

The unit is four years old. I just spoke with Nisonger yesterday, who have a three week turn around time at the moment. They confirmed that the reverser in non-rebuildable and must be replaced. They also said that it is rare for these units to fail, and that I am in a very small minority. Guess I should go buy some lottery tickets now

[mickmate]

Nisonger is the place for Smiths gauges they have rebuilt, recalibrated and repaired them for me. I have had mileage set correct for the car on new speedometers also. The 90 can be used as a reverser or just as a 90. Check which way yours is set up. They can also be found here
Search Results for speedometer 90 - SummitRacing.com

[Archrms]

Good thing you mentioned the mileage adjustment, as I would like to have them add some miles to it to compensate for the mileage I've put on the car since it stopped working.

[Blas]

I know I have a full set of gauges in a box somewhere. Want me to check if I have a spare Speedo?

[Archrms]

I appreciate the offer Blas, but I can wait until they fix mine.