Make Your Own Throttle Cable
- Gerry Masterman

As of:  16 April  2006 


       A recent thread on "The MGB Experience" web site made me think about sharing this with every one of my MGB friends.  Instead of buying throttle cables from Moss or VB and having to deal with the questionable quality of some of the imported items, I decided one day, to try to make my own cables.  This is how I went about it.

First, a trip to WalMart yielded a pair of bicycle brake cables to be used as my raw materials.  The cables come with one end already attached and a 3/8" diameter barrel that slipped around this end to provide a larger end.  This end can be used as is, but I cut them off and start from scratch.  I make up some one piece barrels from brass round stock to replace the supplied ends.

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Notice that there is a funnel shaped hole in one side of the barrel and a smaller hole that goes all the way through, just large enough to slip the cable through.  After passing the cable through from the small side, I spread the wires that the cable is made of so that the cable cannot pull back through the small hole.  I pull the cable back as far as it will go so that the spread section is inside the cavity, and then fill the cavity with solder.  I have used both acid core and rosin core solder and find that either will work as long the cable is good and clean.  I use a medium sixed Weller soldering gun or a big soldering iron suitable for sheet metal use. Both work, but the bigger the better.  A small iron or pencil just does not have the heat needed.  I have even used a torch but found that it was overkill and likely to damage the cable.  After the barrel is soldered on one end, I cut the cable to length.  For SU HIF-4 carbs I use 36" inner cable and a 23" sheath.  I then use the soldering iron and solder to tin  the other end of the cable for an area 1 1/2" from the end.  To tin the cable, I simply heat the cable up with the soldering iron, add a bit of solder so that it penetrates the cable, remove the heat and then before it cools, I wipe it off with a wet rag.  This removes the excess solder and leaves just the solder that is inside the cable.

 

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This helps keep the grub screw in the cable clamp from distorting the cable and causing it to fray.  If you have ever tried to reinsert a frayed cable through the tiny holes in the sheath stop and then back through the cable stop you will remember how hard it is to get the hole cable back through the tiny hole without having a stray wire or two missing the hole completely.  With the end tinned, it becomes one single wire, and is solid enough so that you can clamp down on repeatedly without damaging it.  

 

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The third thing I do is to drill out the little tower that the cable goes through that mounts on the firewall to fit the ferrule on the end of the cable sheath.  I sometimes have to turn a new adapter to reduce the size of the hole so that the sheath will not pass through.  If you sheath passes through the tower, your throttle will not operate.

        BTW, even if you buy new cables for one of the MG parts dealers, I highly recommend that you tin the end of the new cable to prevent it from fraying.  This works on choke cables, as well.  Different car setups require different cable and sheath lengths so it would be wise to measure your old cable and sheath before discarding it.  Oh, and be sure that you clean up the areas where you used solder to get rid of all the flux from the solder.