Speedometer not working

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bizz
Posts: 198
Joined: Thu Aug 04, 2011 7:56 am
Location: Australia

Speedometer not working

Post by bizz »

Hi all,

It has been a while but the old girl is still ticking along. I recently diagnosed a snapped speedo cable (it was indeed snapped) and ordered a brand new one from BMW.

I have disconnected the short section between the cluster and main cable, driving with the dash vent removed i can see that the exposed cable is not spinning, leading me to assume something at the gearbox end is amiss.

Has anybody had a similar experience? Is it possible that there is something wrong at where the cable meets the gearbox? the cable is seated correctly as far as I can tell.

Thanks!
1976 528
T.Hanson
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Joined: Wed Jul 26, 2006 7:39 am

Post by T.Hanson »

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John in Simi Valley
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Location: Formally Simi Valley, Ca.

Post by John in Simi Valley »

Pretty easy to verify if the instrument itself is working. Disconnect the first joint behind the brake peddle and give the shaft a spin. If the speedo responds you know the instrument is OK.
Now it's a matter of where's the disconnect. There are 3 cables and 1 device (up to the tranny) that could be bad. Check each from nearest first.
(You mentioned getting a cable from the BMW dealer, did you get all 3?)
Follow the cable back to the milage counter box. Disconnect the near side. If that works, then reconnect and check the opposite end of the counter box. Then check the cable end out of the transmission.
If all that works, have the car up on the rack and have a mechanic run the engine at idle, in gear with the speedo shaft installed. They can do a visual in the tranny to verify the square drive is turning.
Most likely, you'll find the problem long before this.
Good luck.
John Savage
1980 528i 5-Speed
FirstFives COTM Editor
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