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Speedo problem BT7 - cable rotates but speedo does not

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fishyboy

Jedi Hopeful
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Hi all,
My garage has just replaced the angle drive and cable on my BT7 after the last one tore itself apart (old angle drive didn't have the spacing washer!). However, when connect up the speedo does not turn. The garage said the speedo must be broken and need replacing.

However, when I got home I cut off the end of the old cable and put it in a drill and used this to turn the speedo without a problem, so the speedo is not broken.

The problem must be how the cable if fitting into the back of the speedo. Is there any particular way e.g. should it be screwed in as tight as possible or left slack?

Any help appreciated.

Thanks

Phil
 
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Re: Sppedo problem BT7 - cable rotates but speedo does not

The cable should be screwed into the speedometer just finger tight; i.e. as tight as you can get it with your fingers without excessive force (that's why the 'nut' is a knurled knob, not a 6-sided nut suitable for wrenching).

First, make sure the cable is turning (could be a defective adapter). Disconnect the cable at the back of the speedo and watch it as you take a drive around the block. There were some cables sold a few years ago that were too long, but since yours was working before the adapter self-destructed it's probably OK.
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

Safer option rather than trying to watch it as you drive would be to put the rear up in the air on stands, start the engine and put it in gear. That way as well you can poke at it a bit to see if the cable isn't seated or such without having to watch where you're going.
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

so the speedo is not broken.?

Then take it back to the garage and ask them to find out what they did wrong!!
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

Hi
The cable rotates fine when disconnected from the speedo. It looks to me that the cable needs to extend a little bit longer beyond the collar. Don't quite know how to achieve this.
Phil
Phil
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

Phil
That is a bugger HUH
However,In some of the cars two speedo cables are available. I always use the longest one because it assure me that the routing contains the most generous bends, which circumvents binding and pull back of the core in the tube.
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

I had a similar problem with my rev counter cable, it turned out to be that the end of the cable was only just making into the back of the revcounter and the end had worn and was rotating but not gripping the rev counter female connection. I tested this by squaring up the end of a nail and fitting it into an electric drill to drive the rev counter. A new cable should do it.

:cheers:

Bob
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

I have also found some of the new cable drive ends are not as big as the originals and they spin in the speedo w/o turning it.

Marv
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

A new cable should do it.:iagree:
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

It is/was a new cable!
I unclamped the short sleve and pushed it back a few fractions and then connected back to the speedo. Still no movement. On rechecking the cable the core had also stopped turning. I removed the transmission tunnel and removed the new angle drive only to find the the short square cable from the gearbox side had torn itself up. ****, brand new angle drive down the pan.

I have ordered a new angle drive and will try a refit next week.
Phil
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

Was there a spacing washer installed with the new angle drive????
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

Put "Two washers" in there when you get the new angle drive.?
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

Thanks Keoke.
I now have several washers so Ill give it a try.
Does anyone now if it is possible to buy the short lengths of cable inside the angle drive instead of having to buy a whole new unit?
Phil
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

Does anyone now if it is possible to buy the short lengths of cable inside the angle drive instead of having to buy a whole new unit?

Phil

I have rebuilt them. I do not recall how i removed that short drive bit from the angle drive.
However, i made the replacement using an old speedo cable where i cut the squared end off to the proper length and just inserted it back in the overdrive.
 
Early in my ownership the cable in my BN7 failed at the transmission. Though a friend with a similar Toyota 5-speed setup uses that company's angle drive, which he recommended, I was able to fabricate a new cable from a slightly longer Healey speedo cable, taking care to make a long bend where it attached to the gear box. Perhaps that will work with the standard transmission. The problems I encountered included freeing the cable where it was "trapped" by the tranny cover (basically removing the seats, etc), fitting the Toyota drive piece from the failed cable to the dissimilar Healey cable, and then making doubly sure that I successfully engaged the cable to the speedo to check for length before fitting the drive piece. Yes, I had to do the "fitting" twice, but it is still working well.
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

Many years ago I replaced the broken short cable on the angle drive using the end of an old speedo cable. IIRC, I removed the plug in the end of the unit by drilling a 1/8" hole in the plug and then used a small punch to pry out the plug. Once you remove the screw on top of the unit, you should be able to remove gear holding the broken cable by extracting it though the hole where the plug was removed. I then used a small punch to drive out the remnants of the old broken cable. I then installed the replacement piece of cable into the center of the gear using JB Weld to make sure it didn't rotate. Then use some more JB Weld to replace the plug and fill the small hole.

The repair held for many years and only failed when the speedo gears gummed up and froze.

So yes it's possible to repair, but expect to spend several hours doing the job.
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

I fitted and new angle drive (with two washers) and new cable. With the back wheels jacked and in gear the cables turns fine. When the speedo is attached the needle does not move. I tried just the cable and speedo connected to a drill and the needle works fine. Took the body off the speedo and reconnected everything. I can see the main mechanism inside turns fine and the odometer moves but the needle does not budge.
At a complete loss. I guess I'll have to try a new speedo, but don't uderstand why the needle work fine when connected to a drill.
Any ideas.
Phil
 
Re: Sppedo problem BT7 - cable rotates but speedo does not

fishyboy said:
I fitted and new angle drive (with two washers) and new cable. With the back wheels jacked and in gear the cables turns fine. When the speedo is attached the needle does not move. I tried just the cable and speedo connected to a drill and the needle works fine. Took the body off the speedo and reconnected everything. I can see the main mechanism inside turns fine and the odometer moves but the needle does not budge.
At a complete loss. I guess I'll have to try a new speedo, but don't uderstand why the needle work fine when connected to a drill.
Any ideas.
Phil
Click to expand...
Does the odometer read/move when you're turning the cable or is it just that the speedo needle not reading/working?
 
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