Why do you have to thread it through everything? Tach cables come in two
parts: cable and housing. If you disconnect both engine and tach ends,
you can pull the cable out and thread a new one back in, using the old
housing. Be sure to use plenty of moly grease, to keep the cable
well-lubed. BTW, any speedometer shop can make up a new cable, with the
proper ends.

Question... is a tach cable made up at the local speedo shop an approved
aircraft part?
Does it need to be?
Or does a DAR have to approve it as a suitable replacement part?
Or can an IA do that?

BT