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TR2/3/3A Speedometer question.....

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Hi Karl there is an inner main spring that is very sensitive. If you can get the needle to bounce when you gentle flick your wrist, is a good way to tell at a swap met if the gauge is functional.

Your needle could have fallen off the shaft because they are a push on fit.

Steve
 
sp53 said:
Hi Karl there is an inner main spring that is very sensitive. If you can get the needle to bounce when you gentle flick your wrist, is a good way to tell at a swap met if the gauge is functional.

Your needle could have fallen off the shaft because they are a push on fit.

Steve
Click to expand...
 
Steve The needle is still on the shaft because it still operates the full range when accelerating it just wont drop all the way back to its starting point I think i need to detach the cable from the gauge and lubricate the inner wire of the cable with some sort of lubricant?? Karl
 
Some years back Geo and I were working on my speedo. He showed me where there is a small white dot right before 0 mph on the gauge face. This dot is where to put the needle when replacing the needle because the needle needs a little spring loading and calibration.

So with needle in hand, you set the needle on the dot push the needle down and then gently lift the needle from the white dot and move the needle to zero on speedo with the back of the needle resting on the perpendicular post and that is the basic calibration and preload.

Sounds like you need to calibrate the needle. They pull up and off.

Steve
 
With the outer shell of the speedo removed, you put a finger on the escapement wheel and move the
needle to zero it out. It should fall back easily but not slam down when moved. It is an analogue gage and will never
be used in a court of law!!
A gentle touch is required here
Mad dog
 
Think about it this way: as the pointer approaches zero, the spring unwinds and there is less and less force on the pointer. As a result, even the slightest additional friction will cause the pointer to hang up. Before taking off the pointer and resetting it, be sure it is moving completely freely.
 
One last, as mentioned it doesn't take much to hang up the needle at the lower part of the scale. Sometimes loosening or tightening the cable retaining nut on the speedo can help the alignment or pressure on the speedo and help the needle move more smoothly and freely. As also already mentioned, these are very analog cars, or fiddly as I like to call them.
 
karls59tr said:
Does anyone know why the speedometer needle would fail to return to zero and hang up at 8 mph?
Click to expand...
Likely muck accumulated over the years. Google a document written by TR owner Anthony Rhodes on Smiths Speedometer repair. He goes into detail on how to service and repair these speedometers and odometers. It is the best doc out there for this task. It is free, lots of clubs reference it.
 
If you have recently replaced your speedo cable, remanufactured inner cables are sometimes a bit too long and can cause excessive pressure on the mechaniusm. Try loosening the cable a few turns and see if the pointer drops to zero. If it does, then remove 1/16" from the end of the inner cable at the speedo end and try it again. You can also test it by fitting it in the Rev Counter position and seeing if it returns to zero when the engine is switched off. The cables for the Speedo and the Rev Counter rotate at similar speeds, so you will not do any damage.
 
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