Early Speedo Just Stopped

While driving my 78 lp400s last fall, the speedo just stopped working. I think this is my next "to do" on my list. I see that the cable goes into the left front hub. Is the problem either a)inside the hub or b)right behind the speedo gauge, or c)?????

Peter - there is a very high probability that it is the pin that goes from the bottom of the cable to the spedo drive unit in the front left hub. In the QV it took me about 1 hour to replace (lambo part costs about $10). Should be the same.

Mine smapped when I hit a pot hole. Good luck. Alex

If you go to the trouble of taking the speedo cable out to check it, I would STRONGLY SUGGEST you go ahead and remove the right angle drive. Take the drive apart to check the wear on the gears and reassemble using a white lube. DO NOT reassemble using the wheel bearing grease that is in these things. The white lube is just right for the job and not heavy as the wheel bearing grease is. THE RIGHT ANGLE DRIVE IS NO LONGER MADE. AND HAS NOT BEEN FOR YEARS. Anything you can do the prolong its life will help.

Chadbourn Bolles

803 798 ****

If you go to the trouble of taking the speedo cable out to check it, I would STRONGLY SUGGEST you go ahead and remove  the right angle drive.  Take the drive apart to check the wear on the gears and reassemble using a white lube. DO NOT reassemble using the wheel bearing grease that is in these things. The white lube is just right for the job and not heavy as the wheel bearing grease is. THE RIGHT ANGLE DRIVE IS NO LONGER MADE. AND HAS NOT BEEN FOR YEARS. Anything you can do the prolong its life will help.

Chadbourn Bolles

803 798 ****

 

So, if parts are no longer made.....if a gear is worn....what next ??

At this time you are out of luck. I have been hunting for them for years. One day I am sure I will find what they fit besides the Lambo.

Chadbourn Bolles

803 798 ****

This is about to start being a big problem for everyone. The original castings were not very well designed, and the gears have no bushings for reverse loading, so they wear a lot in reverse (don't drive in revers down the highway I guess.....).

 

I have had to replace a couple now, and the supply is gone. Next option is for enough of them to fail that we can get some custom made for less than an arm and a leg (the casting probably isn't so terrible but having the gears made is very expensive I understand)..... volume would of course bring down the unit cost. From what I hear, I think we'd have to have a 100 or so before it came even close to reasonable.

 

Another eventual option is that I know you can build a fully electronic replacement with magnetic pick-ups off an output shaft or something, but you'd have to put the original speedo head on a shelf and it would be expensive (wlthough might finally be accurate).

I happen to have a new drive, but the gears are for another car. I also have a good correct drive. If someone wanted to copy what I have, that would work.

The housing is made of pot metal, and should be reproduced in real aluminum. A friend of mine said he could make the housing out of billet, don't know what the cost would be. And the housing is one of the parts that fails.

It is funny that Jaguar and other British cars have used something like this for years and you don't see failures there.

Chadbourn Bolles

803 798 ****

On my LP5000S the cable had somehow got kinked so much so that the outer helix sheath failed. Rosso Corsa are currently having a replacement cable made for my car and tell me that while they are at it they are getting another two made - so if it turns out that yours is a more serious cable failure you could call Michael at Rosso Corsa (+44 208 9612332).