View Full Version : Odometer failure

09-29-2006, 12:21 PM
My odometer is not working. The speedometer works, however the odometer does not turn. A friend that is a mechanic has told me to replace the entire guage. He states that everything is hooked up correctly or the speedometer would not work. Is this true? Anyone have any oppinions to the contrary? Is it possible to repair this in any way? If I do have to replace the entire guage, does anyone have an extra working one to sell? Thanks!

09-29-2006, 01:14 PM
Hi Brent,

The odometer on my TR4 died many years ago. The speedo continued to work fine. Your mechanic is right, it's most likely hooked up fine, or the speedo wouldn't be working. However, you can most likely have the gauge repaired and it might be worth rebuilding the whole thing at one time rather than just fixing the odo.

If you have a lot of speedometer error due to a change in the gearing in the differential or tire sizes different than the originals, it would be possible to correct that, too, while it's apart, if you wished.

I haven't really looked into getting mine fixed yet, so can't recommend anyone in particular, and I don't know the prices you might expect. But, there are a couple places that repair TR speedos (check the archives here or Google on the Internet, or perhaps some other BCF members can make a suggestion). Also, I've heard, but can't confirm, that repairing the speedo or modifying it for diffeent gear ratios/tire sizes isn't all that difficult a do-it-yourself job, if you feel up to it. There have been a couple previous posts about this and ISTR seeing a resource on the Internet with a lot of detail.

Hope this helps!


09-29-2006, 01:17 PM
It could be repaired by a gauge repair shop such as Nisonger. Chances are, something snapped or cracked in the gearing between the speedo and odometer set.

Technically your mechanic is correct. If it were the cable, neither would work.

If you do buy a used gauge, you will have to set the odometer to match yours. The replacement may be either lower or higher. This will require disassembling the gauge and knowing how to do it without making it looked hacked for roll back purposes. Maybe you can see if you have a speedometer repair facility in your local area?

09-29-2006, 01:32 PM
Hi Brent,

You might want to go to this website and read his writeup of Speedometer and odemeter repair


09-29-2006, 03:00 PM
There have been a couple previous posts about this and ISTR seeing a resource on the Internet with a lot of detail.

[/ QUOTE ]

Ok, I am with you all so far. Can someone tell me what "ISTR" is?I also really appreciate the link for the rebuild. If I can find the parts, I will give it a go. Thanks!

09-29-2006, 03:06 PM
I had that happen to mine and was able to ix it myself with no problem. The guy who told you that you have to throw it out is wrong. The odometer is a mechanincal item that uses a series of gears. If I recall correctly mine had a worm and wheel and one of those had stripped. I think this is a common problem as the grease gets old and makes it harder for the number wheels to turn. Once the gear is stripped nothing turns in the odometer any more but the speedo works fine. Just open the thing up, find the broken gear, clean all the old grease, replace the broken gear, re-grease the works and put it back together and you are good to go. I did this back in 1985 and it has worked fine since.

Geo Hahn
09-29-2006, 03:13 PM
ISTR that means "I seem to recall".

I keep a couple of extra gauges (TR3/4 type) and freely exchange parts among them for the best operation. Failure of just the odo may mean that the pawl that operates it has slipped loose... if the parts that actually drive the odo were binding your speedo cable would promptly break (personal experience).

An eBay 'bottom-feeder' (like me) can usually pick up decent gauges dirt cheap. The key number for calibration purposes is the 4 digit number on the face which ISTR indicates the number of times the cable turns in recording one mile.

Tony website (noted above) has enabled me to disassemble, repair, reassemble & calibrate several of these instruments. They're really pretty basic with only one fragile/fussy part (the hairspring).

09-29-2006, 04:16 PM
Thanks for all the info guys. I think once it gets a little colder, I will have to give it a whirl. I just called Nisonger, they want $140 to totally work it over. I will try to fix it first and send it to them if I can't figure it out.

09-29-2006, 04:43 PM
Aloha Brent,

In my experience, odometer failure has been caused by the fiber gear that drives the odometer was stripped. it has always been the main odometer that has failed. The trip odometer on my MG and Triumph are driven by a different gear. Good luck.

09-29-2006, 05:03 PM
My TR3 odometer(s) quit, and when I opened it up, both pinions for the total mileage and trip mileage were stripped. Yes, they are those fiber type gears. They are attached to a shaft that rides in the aluminium housing, and the shafts seized up in the housing. It looked as if the grease had dried out so much that it became more glue then lubrication.

I took a chance, and bought a crappy looking speedo on e-bay for $30, hoping the odo gears were in good shape. Well, they were, and I was able to get the odos working again.

09-30-2006, 10:14 AM
Can anyone tell me if all of the internals of the speedometer from the different model TR's and years are interchangable? This would assist in finding another speedometer to try to find any needed parts. Thanks

Geo Hahn
09-30-2006, 12:35 PM
They will differ. The 4-digit number on the face of the unit indicates it's calibration... the difference from one calibration to another will mainly be a different number of teeth on the odo gears -- likely the part you will need to replace.

There are plenty of used ones around (they don't really wear out) so your best bet will be a unit that matches yours.

10-02-2006, 09:02 PM
Ok, I have finally had time to look at the speedo and post. I am looking at 2 numbers on the face. 1 being the serial number: 6409/08A just below the trip odometer on the left. And 2 a second number on the right side just below the trip odometer. "1120" Is the 1120 number the number I use to find a guage with the same size gears? Thanks for the help. And does anyone have one?