Intermittent speedo operation.

[modelbuilder]

I posted a question quite some time ago regarding my speedo which works normally for about 3 miles then slows down and stops working altogether.

 

I thought it might be worth repeating in case anyone else has had a similar problem. to date I have replaced the speedometer with a Revington recon unit, replaced the speedo cable although the original was only 12 months old, fitted another recon angle drive but the same problem persisted.

 

Talking to Overdrive Services who had reconditioned the J type overdrive, he thought that it might be the speedo drive pinion because some of the early replacement ones were problematic. I bought a replacement at Malvern, fitted it today and bugger me, it's just the same.

 

Now logic says that it obviously is one of the aforementioned parts but I'm really at a loss to know where to go from here. I think my next move is to run the car with the speedo disconnected and get a passanger to see if the cable inner stops. It's just that the symptoms are exactly the same as before I embarked on this saga which is weird. The only plus is that he keeps the mileage low!

 

Rodders.

[Richard Crawley]

Can't remember your original post so I may have said this already. When my spedo did the same thing I found 2 problems;

 

The nylon angle drive worm was not securely fixed to the short length of cable that drives the inner cable socket. It was a new unit so I used my old innards in the new outer casing.

 

Unfortunately this did not permanently solve it; on disconnecting the cable connection from the spedo head & running the car in gear I found that unless the cable was forced hard down into outer cable, it stopped turning; even the slightest movement & it stopped. On investigation I found that the inner cable was slightly undersized when compared to my original & the square on the ends were very poorly formed; again, this was a new cable. I put my original still good inner cable into the new outer cable & problem solved with no trouble since.

 

You don’t need to run the car on the road to do the spedo head test; providing you have a standard & not a limited slip differential fitted just jack one rear wheel off the ground using a decent trolley jack, start the engine & run it in gear. Be sure to chock the other wheel firmly with 2 blocks of wood to stop any movement & only run the engine as fast as you need to see what’s happening; 2nd gear should be enough.

[modelbuilder]

Can't remember your original post so I may have said this already. When my spedo did the same thing I found 2 problems;

 

The nylon angle drive worm was not securely fixed to the short length of cable that drives the inner cable socket. It was a new unit so I used my old innards in the new outer casing.

 

Unfortunately this did not permanently solve it; on disconnecting the cable connection from the spedo head & running the car in gear I found that unless the cable was forced hard down into outer cable, it stopped turning; even the slightest movement & it stopped. On investigation I found that the inner cable was slightly undersized when compared to my original & the square on the ends were very poorly formed; again, this was a new cable. I put my original still good inner cable into the new outer cable & problem solved with no trouble since.

 

You don’t need to run the car on the road to do the spedo head test; providing you have a standard & not a limited slip differential fitted just jack one rear wheel off the ground using a decent trolley jack, start the engine & run it in gear. Be sure to chock the other wheel firmly with 2 blocks of wood to stop any movement & only run the engine as fast as you need to see what’s happening; 2nd gear should be enough.

Thanks Richard, it has to be something stupid and simple like you suggest. I bought the car from a member who had done a wonderful job of rebuilding the car and as it was a LHD/RHD conversion the speedo cable would have been replaced. Quite possibly both that cable and the one I subsequently purchased were both of the same manufacturer. It does appear by the postings on this forum that many of the parts supplied today are less than satisfactory. My reasoning tells me that it has to be either the cable or angle drive but there is no point in replacing these parts endlessly from the same source so HAS ANYBODY GOT A SPARE GOOD O.E. SPEEDO CABLE TO SELL ?

 

Cheers.

[jonlar]

Hi Rodney, I've posted another reply in the Buy, Sell bit.