The choke cable on my MGB is of the later type "pull and twist to lock". The cable itself is stranded Bowden cable and this tends to get snagged if its removed and refitted to the carb trunnion too often. It helps if the cable end is tinned with solder (mine wasn't) and after two carb problems the end was frayed into a half dozen vicious wire strands. I'd cut this mess off before and the cable was now too short to repeat that solution. The MGB is thoughtfully designed such that the bonnet prop is positioned such as to obstruct access to the carburettors and so any fraying of the cable coupled with an obstructed view and a ridiculously small cable end trunnion (why can't it use a nipple like the the throttle) means that fitting a cable that is anything other than perfect at the end is nigh on impossible... replacement is the only solution.
Back in 1972, when I got my very first car, you could wander into Halfords and amongst any number of now sadly specialist items, there would usually be a whole card of bag-wrapped "universal choke cables". Sadly no more, these are now specialist items, often from China and just take too long to arrive. MGB specific replacements are expensive and can still take a week to get here. I ordered one, but my MOT was due in a few days. I don't think its an MOT item but the car is hard to start when cold without a choke. I'd thought I had plenty of time, but as the days ticked by the non-arrival of my cable lead me to try and fix the one I had. I had some spare Bowden cable from my motorcycle, although push-pull cable (solid wire) would be better. Its not strictly needed for this application but it is so much easier to slip into the carburettor trunnion.
Removing the cable is easy, the outer was fine in my case so I just pulled the whole inner cable out into the inside of the car.
Examining the handle showed that the turn to lock cable handle is made in two halves, each is actually a length of semicircular channel but one is smaller diameter than the other and fits inside the larger to form a central hollow into which the cable can slip. This also creates a curved and a flatter side as the section is asymmetric. The cable is inserted into the hollow between the channels and the end of the smaller one is then crimped flat for about 1cm to hold it.
The cable doesnt pull out so I cut the rod section just behind the crimp By cutting carefully and rotating the rod I could cut through both sides without damaging the cable inside. Once cut Around I could detach the crimped section and then pull the remaining cable out from inside the rod
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| Cut around the rod section, a gentle pull then detaches the crimped end (left) and pulls out any remaining cable. |
I fixed the rod section vertically in a vise and found that the central channel was actually now pretty shallow
I drilled carefully down inside the rod to deepen the central hole to 1cm and checked that the new Bowden cable would slip inside.
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| Drilling inside the rod to open a channel for the new cable. |
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| Check the new cable can slip inside. |
The cable handle slides and locks by virtue of its asymmetric section, the wider channel section forms a curved side, whilst the smaller radius sits in side it forming a flatter side. I thought that if I'm going to crimp the rod section it will be important not to flatten the larger curved side. I took a short length of steel tubing and sliced it in two to create a hollow concave support.
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| Splitting a short length of steel tube |
I filed the edges of this channel until the curved side of the rod could fit inside leaving the smaller channel section projecting above.
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| Half the tube... |
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| Into which the rod section can lie. |
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| When the larger channel (rounded side) of the rod is held against the inside of the tube the inner channel (flatter) section protrudes above it. |
Obviously this isnt a perfect fit but its pretty close. I could then fix this into the vise and insert the cable before crimping the inner section by tightening the vise.
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| Resting the handle rod in the curved support and crimping the cable into position. |
This produced a textured crimp on the inner surface but maintained the curve on the outside.
Having checked the cable was secure I cut the free end to match the old cable length using a pair of Draper cable snips
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| cut to length |
And tinned the free end with solder
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| Tinned end- its really hard to do this once the cable has become greasy in use as the solder wont stick, best to do it now. |
I sprayed the length of the cable with silicone lubricant and inserted it in to the existing outer from inside the car. The cable inner slipped relatively easily into the existing outer, had to jiggle and twist a few times to find the route but it was relatively straightforward. I had to file the crimped section of the rod smooth so that it would slip easily into the existing dashboard flush mount. Its action was pretty smooth (but not quite as smooth as the original) and the twist-to-lock function also worked.
The tinned end slipped easily into the car trunnion and so job done! This would have saved about £20, but as I said I have a cable on order anyway. However this is certainly a viable fix and I'm not going to rush to swap it.
