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speedo cable

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duckspuddle

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My speedometer without warning abruptly quit on a trip this weekend. I disconected the (newish)cable from the back of the instrument, and observed that the inner cable does not turn as the car is in motion. It seems engaged in the angle drive (A-type OD). The cable looks healthy. I tried another inner cable which doesn't work either. I'm almost certain the problem lies either in the angle drive or speedo drive in the OD. Are these prone to failure? The angle drive is about 10,000 miles old. Can the bolt that secures the speedo drive in the OD be accessed from the panel in the transmission tunnel? I don't relish the thought of removing the tunnel.
Joe
 
The end of the cable may have snapped off, that happen to me last year, I still have yet to fix it!
 
I can't say if you have an access panel that will allow this, but if there is an access panel on that side I can't think what else it would be for so it's worth a try. I had to cut my own access panels so I made sure the angle drive was something I could service with the tunnel in situ.

Apart from finding what broke and fixing it you should also confirm that the innards of the speedo haven't locked up. Mine did that and when I replaced a broken cable I promptly broke the replacement cable. In my case the shaft of one of the odo gears had siezed due to a spot of corrosion. Easily disassembled, polished & lubed but I should have spotted that problem before sacrificing a 2nd cable. To check it insert something (such as a small screwdriver) in the rear of the speedo and see that the input spins freely.
 
Joe,
Try pulling the inner cable completely out and inspect the other end. In mine the speedo lubrication had gummed up from age and put too much strain on the cable. I took the guage apart and cleaned it up. I cut off the speedo end of the cable and can use it to check speedo/tachs as Geo Hahn describes.

Jeff
TR6 CF13816U
Honolulu, HI
 
I figured out what was wrong with my speedo. The gauge is fine, however the cable part of the angle drive is chewed up. If I put a cable in the transmission (omitting the angle drive) everything works fine. I guess I just got a bad angle drive. It only lasted about 5,000 miles. I hope TRF's lasts longer than Moss's. They're probably the same. Thanks for all the advice
Joe
 
I'll ask & maybe you'll get an answer... do you have to use an angle drive on a TR6 OD?

On a TR4 you can use an angle drive & the standard cable or no angle drive and a longer cable. Perhaps on the TR6 with a Type J OD there is some interference that precludes just using a longer cable though I thought I heard (read) of this alternative with the cable arcing out under the floormat then back to the tunnel and over the bellhousing.
 
To the best of my knowledge, you must use an angle drive on a TR6 with a "J" type OD. I know because mine broke as well and I had to replace it to keep the speedometer working.
 
I'm almost certain you have to use an angle drive with an A type OD. otherwise, the cable exits the OD perpendicular to the tranny cover. There just isn't room unless the cable bends 90 degrees
 
duckspuddle said:
I'm almost certain you have to use an angle drive with an A type OD. otherwise, the cable exits the OD perpendicular to the tranny cover. There just isn't room unless the cable bends 90 degrees
Click to expand...

No, it's not absolutely mandatory, although I think it's "original" to TR6. You don't have to use an angle drive with an A-type: There is a very long, special OD version of the cable available, that was used on TR4 (and perhaps some other models). If you look up TR4 speedo cables from any of the vendors, you will find two choices: One with OD, the other without.

By using an angle drive it's possible to use the shorter cable, which is the same as was used on gearboxes without OD.

Angle drives need to be greased every so often, to help keep them alive. If not serviced, they won't last very long. I've heard that the modern repros aren't as long-lasting as the originals, either.

I'm planning to install an electronic speedo in my TR4, so I've got an original angle drive that I'll be using as adapter to spin the speed sensor, not a cable. Hopefully it will put less stress on the drive and extend it's life.

Cheers!
 
Alan, as always, never satisfied. Like the idea keep us posted.
 
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