speedo cable

[mickl]

The speedo on my 75 berlina has stopped working after being very erratic for a while. I have pulled it out at both ends and there does not seem to be much wrong with it to the eye. The cable is not severed either.
The weird thing is that even though tyhe speedo is not registering, the odometer is moving maybe an extra 0.1km every 10km the car drives, however, the tripmeter is increasing at a faster rate (but still only about one tenth the distance travelled)
There are no clicking or whirring noises behind the dash and I have tried angling the cable a bit to see if it bites with the square hole ...but no luck.
Any ideas anyone?......or should I just order a new one?
Mickl

[Barry Edmunds]

Mickl

Have you checked both ends of the cable to see if they have rounded off, or perhaps the conenction to the speedo or water pump may have rounded off?

I'd suggest you remove the cable from the water pump and turn the inner by hand  (or using a drill at very slow speeds) to see if this registers or disconnect the cable from the speedo and then start the motor to see if the inner cable turns.

If you have already disconnected the cable from both speedo and water pump try turning one end (by hand) and check that the other end also turns at the same speed.

If the odometer is registering but not the speedo it could be the gears in the speedo.

I have got a spare cable if you would like to try it.

Barry
0405 383 431

[mickl]

Thanks for the tips Barry. I think the square ends of the cable are OK but I will take a much better look now. I will disconnect the cable from the speedo and take it for a run to see if it is turning at the speedo end of the cable. If it is then i guess the gearbox end (the tacho connects to the waterpump, doesn`t it??) and the cable itself will both be OK
Will post another reply later today on what I find.
Thanks
Mickl

[mickl]

Progress report after disconnection: The cable is good and its fitting at the gearbox end is fine as the cable is spinning well at the speedo end. The square end of the cable is good too and not rounded off at all. It appears to me that the outer sheath is too long for the cable itself as the end of the cable protrudes only 2 or 3 mm past the end of the sheath fitting. Pliers will pull it out so there is about 8mm showing but it easily creeps back in and I don`t think it is actually going in far enough into the back of the speedo.
I did another test by using a spare speedo cable from a 260z which is the same size but pokes out about 1 cm from its sheath. I plugged it into the Berlina speedo and screwed it up then attached a power drill to the other end of the cable and sure enough, when the drill is in reverse, the speedo indicator needle shoots around as it should.
So....how can i shorteb the speedo cable sheath to make the square end piece fit further into the back of the speedo?? It looks like it will not be possible, or is there some way?
Thanks
Mickl

[colcol]

Try using a small pipe cutter with a wheel disc on it that plumbers use for doing neat cuts on small pipes, most likely $10 at Bunnings or try carefully cutting with a fine hacksaw blade, carefully NOT cutting the inner cable or getting a shorter cable made up for the outside by a speedo cable maker, i had one made up years ago in Greensborough, but he shifted to, i think Eltham, took the bits there, told him what i wanted, and he made it on the spot, or maybe get a new longer inner cable made up, Colin.

[Barry Edmunds]

Mickl
From what you have written it sounds like your 'old' cable is not long enough. It might be cheaper to try and modify your old cable but for the cost of a new cable (inner and outer) about $40 as I recall, it would be better to get a new unit. Speedscreen in Ascot Vale can supply fairly quickly.
Barry

[mickl]

Thanks for the recommendation. For only $40, a new one is the way to go i think.
Mickl

[mickl]

It`s fixed! The secret was to detach the cable from the gearbox end and push as much inner wire into the outer sheath (and hence into the back of the speedo gauge) as possible, leaving only about 7 or 8 mm poking out at the gearbox end. The gearbox end only needs that amount poking out to seat nicely into its fitting, whereas the speedo end needs well over a cm to engage with its housing. Previously I had pushed well over a cm of the square cable into the gearbox housing which didn`t leave enough at the speedo end.
Feels good when you finally get things sorted out.
Mickl