Help w/ jamed cable

[Shanman]

I'm trying to fix a bike for someone. Their rear derailer is not working. I thought it was the shifter, but when I went to remove the cable it wouldn't go through the first cable cover. So there an easy way to fix a jammed cable or do I just need a new cable and cover?

Thanks for the help.

[KLydesdale]

If the cable jamming in the housing because things are worn, dirty and/or frayed, I'd replace both it and the housing. Worn and dirty cables and housings are a primary cause of shifting problems.

[Joe_C.]

He is right! Replace the whole housing and cable, could be kinked or just full of dirt and junk. Tell your friend to use a lube in the housing, like T-9 thats what we used in the shop, and it will help to clean and lubricate the new housing and cables.

[Shanman]

Just cut the housing open and noticed frayed threads and some rusting or dirt. I wasn't sure what an LBS would charge for a new cable and housing with installation, but I didn't want to open up his shifter and have springs going everywhere. Once was enough for that. I sent him to the LBS.

Thanks for the help

[Joe_C.]

Most shifters don't need to be opened to replace the cable.

[Shanman]

Joe,

It's some old-low-end-shimano-rapid-fire-push-push-style shifter. There is a phillips head screw on the top of the unit right in the middle. I just don't want to make it worse.