Speedo Cable issues GT6 O/D MKIII

[Timos]

Hi everyone,

 

So i have recently changed out the speedo cable and angle drive running off my overdrive as the previous one was incorrect and snapped inside the pin, thankfully i was able to remove the snapped pice and install a new angle drive (from rimmer bros) i installed it exactly as instructed to do so with the washer, i got to about 80miles and the it is broken again, i haven't check but I'm assuming its in the same place, the cable is snapping inside the pin coming from the overdrive, has anyone else experienced this? i figure it could be one of 3 issues

 

1. Speedo cable has a kink in it (it does not)

2. There is an issue with the pin in the overdrive unit.

3. The speedo is jamming stopping the cable and making it snap in the right angle drive

 

any help would be much appreciated, as this is driving me nuts haha.

 

thanks

[Ben Caswell]

Another possible cause is that the little short cable inside the angle drive is too long and has no free play.

 

You may need to use two washers between the outlet and the angle drive.

[Pete Lewis]

There have been reports of angle drives being a bit inferior but this is looking like the speedo head

spindle is in trouble

 

you should be able to finger twiddle the exposed end of the cable , os there any resistance?

 

 

or pull the head , remove the glass rim and remover the guts then you can oil the main spindle

and its housing. They do sieze with aged dried grease

 

hardest job is getting the rim sticky o ring rubber to release

 

 

available in mtr lengths from bill rarebits4classics and make your own very cheaply

 

pete

[Timos]

Thank you both very much for the advice,

 

I will be taking off the angle drive and the speedo today to have a proper look,

I'm curious about the 'may require 2 washers' the part i purchased stated that it was for a GT6 MKIII O/D and that i had to use one washer, i did think one of the parts looked rather long but then i haven't seen one for this model of car before. just before it broke i saw the speedo go a bit crazy. th is could get a bit expensive if i have to change it every 79.9 miles haha

 

Best Regards

 

Tim

[Clive]

I heard the latest repro angle drives are OK, but no personal experience, still using genuine old ones.

You can repair the agle drive with a bit of effort. Get the flat plate off(old ones had 3pressed bits that need sorting to get off) then the internal bits come out. Knock out the remains of the broken drive, then get an old speedo cable and cut the ends off. Pop into where the old broken bit wasand fix. I have used in weld and proper MIG. Reassemble, and good to go.

I replace a speedo cable if the angle drive breaks, as easy to do and often/usually the cause of the break.

One more thing, don't be fooled around into thinking suppliers keep a variety of (in this case angle drives) for each model,they are often generi. Even things like spitfire front springs many sellone sizefits all,which explains the ride height issues seen on many.

[Pete Lewis]

echo Clives thoughts, these are all one of the same .

 

the speedo is looking a good cuprit the main spindle often starts to seize,  as i said the hardest is once you relieve the rim clasps  the  rubber ring will have goo'd the glass and inner rim 

 

two screws in the back release the mechanism and you can see the housing for the drive spindle , this can be undone and removed but care needed and never ever remove the needle from its spindle and the alloy disc drive plate, or the hair spring unwinds and you have no clue where to re tension it  .

 

the main drive spindle often has a spiral groove to return any oil that has migrated up the cable , this fills with old solid grease and becomes stiff  

 

dont twiddle the oddometer rolls,   and the simple pawl lever for the  ratchet that prompts the rolls to index may need a small dab of lube .

 

if speedo cables are  found to be too long  tooshort the outer case is a spiral wound case which if you grip one end and wind the opposite end the outer will grow or shrink  depends which way you turn it .  you can certainly gain upto 10mm .. but .not 20mm  in  the outer sheath .

 

Pete

[Timos]

Thanks Clive and Pete

 

I have the speedo off now and in bits on my work bench where i cleaned it and greased it up, i must admit i was a little scared thinking it would all just go BOING with springs and cogs everywhere haha but glad to say this didn't happen, i will test it tomorrow with an old speedo cable and a drill.

 

 As for the right angle drive, the new one i bought recently seemed to work fine with my fingers, but it does not come apart, i did however keep the one i took off which does, i will take a look at it tomorrow and chop up the old cable and see if i can repair it, fingers crossed on that mission ( i actually love stuff like this)

any idea on how long it should be? 

 

Best regards

 

Tim

[Pete Lewis]

apart from not too long or not too short  ..... sorry  No

[Ben Caswell]

Hopefully you can read this.

[Timos]

Thanks Ben,

 

I have purchased that same angle drive and it came with those documents which i followed but still had an issue.

 

Peter, i managed to get the blasted thing apart, i also tested it with a old speedo cable and a drill, it ended up doing the same thing (twisting off the end of the speedo cable) so by process of elimination i think you were spot on, I'm just unsure on how to clean the thing, scared of the springs departing the unit haha 

 

best regards 

 

Tim

[Pete Lewis]

Memory is a bit senior on this but the back end should remove and leave the discs and hair springs that are 'needle' side can be left as a sub assy and undisturbed

 

the drive spindle can be removed and greased lightly

 

its not rocket science just dont take the needle off its shaft or let it fly over the needle stop

 

we had a smiths demag and remag calibration machine which rarley got used but I reset my austin maxi

speedo it took a morning of power up , the electro magnets stopped al the clocks and pace makers in the factory

but purseverence prevailed ..

 

so just stick to stripping down the input mechanicals and you will be fine

 

pete