Gearbox linkage cables

Hey guys, so.... fortunate for now my cables are fine and hopefully stay that way for sometime. Humour my ignorance here, as many people fit different boxes In the A2 (6 speed etc) , in my mind, if the cables are long enough from say a 1.4tdi fabia or polo, why can't you get the gearstick tower and assembly, cables and shifter tower from the fabia and fit them in an A2? Surely all the fittings would then work. I'm assuming that a slightly longer cable could maybe have a slight curve to absorb the length and it would still work? Hopefully my thinking makes sense to you guys and I would appreciate it if this wouldn't work (other than maybe minor modifications) , if someone could explain why. Thanks guys. All the best for this coming year! ;)
 
Little Dog said:
Thank you @MARTYN for posting that picture. It is the first picture I have seen of a failed cable. I am of the opinion that that is fatigue caused by an idling diesel engine.
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Could that be exacerbated by excessive drivetrain movement because of (for instance) failing/failed dogbone over a length of time?

Out of interest, what are the criteria underpinning your diagnosis/opinion?
 
Robin_Cox said:
Could that be exacerbated by excessive drivetrain movement because of (for instance) failing/failed dogbone over a length of time?

Out of interest, what are the criteria underpinning your diagnosis/opinion?
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I’ve been riding cycles for 50 years. Outer cables between two fixed points cause no problems. Yes @PlasticMac it’s an outer cable failure. That outer cable on an A2 TDi would be equally reliable; except one of the fixed points is on the gearbox which rocks with the engine.
Leave the engine idling or drive with a soft dog bone and that joint is subject to forces that it could do without. This is because the engine and gearbox rock back and forth.
Just a hypothesis at this stage but one I favour.
The other I like is the sticky tower. But if the tower were to seize solid there should be no stress on the outer cable unless the dog bone is soggy. I think? I’d have to draw up the forces.
Edit, possible issue with my thinking, I assumed gear change cables pull only. I’ll have to take a look at my cables and tower.
Edit2 if the cable bends and it pushes then a sticky tower or gearbox would strain that point.
Looks like I’m no further forwards, except I know it is the outer cable that fails 🤷‍♂️
 
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Finally got to my lockup and checked out the tower on my gearbox. The cables do push and pull. One more so than the other. If the tower seized or was just stiff then the extra force to shift gears would pull at the outer cable.
I now need to look at the cables in the car but the weather needs to improve fitst.
 
Little Dog said:
Finally got to my lockup and checked out the tower on my gearbox. The cables do push and pull. One more so than the other. If the tower seized or was just stiff then the extra force to shift gears would pull at the outer cable.
I now need to look at the cables in the car but the weather needs to improve first.
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I think the push force will be, (should be), much less than the pull force.
I'd theorise, that if the linkage/cables is set up, (adjusted), correctly, there's, (probably), almost zero force on the push cable, as the push from the gearbox end should equal the pull from the tower end.
So, as you say, if the balance between the two is not setup very precisely, the push force will act on the sheath.
Mac.
 
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If the tower bearing is too worn, that causes difficulty in the mechanical indexing of the gear selector rod. It’s trying to select 1st and3rd at the same time or 2nd and 4th at the same time. Makes the gearchange feel like it’s the cables. I have exactly the same issue at the moment on a friends tdi75.
 
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