Any tricks on threading an internal brake cable?

[sadiqgill]

I have an early 90's Colorado and can't seem to get the rear brake cable though the top tube....HELP Please!!

[Louis]

Too late for this one to help you, but the trick is to run a long housing liner / sleeve over the old cable before you remove it, then tape that liner in place, so when it comes time to insert the new cable you just slide it into the existing liner, fish it out the end, then remove the liner...

[oliver1850]

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[scrub]

I have never tried this but remember talk of putting a piece of string in the tube and vacuuming it out the side and then using the string as a guide.

[vqdriver]

Try a very small magnet on a stick. A wheel magnet shaved down works well for this. Or you may find one in your kids science kit.

Then tie a small piece of metal to the end if a string. Put the metal in one end and the magnet in the other. Pull it out and use the fishing line to guide in housing or tubing or whatever. The actual cable comes last.

[oliver1850]

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[sadiqgill]

I had a suggestion from an aerospace engineer who suggested light gauge safety wire; using it to thread through and then a guide. I ended up using the wire and then when I had it through, I butted the brake cable end up to the wire and then wrapped both the cable and wire in a thin layer of packing tape which I trimmed to the bare width of the wire/cable. I gently pulled-pushed the assembly through the two cable openings--success.

I tried the vacuum-string trick and had no success. I also messed with magnets since the wire was steel, but they seemed more intent upon sticking to the top tube and potentially scratching it, so that was a short lived experiment.

As I just purchased the frame, I had no opportunity to leave in the prior cable. In the future, when replacing the cable, I will leave in a "guide piece" and employ the butted packing tape method.

Thanks for all the comments and suggestions.

[mpetry]

+1 on the fishing line / vacuum cleaner trick! that'll work.

Mark Petry
Bainbridge Island, WA

[Bob Loblaw]

Run the cable through first. Tease the end out with a spoke or needle nose pliers if necessary. Then thread the housing onto the cable back to front and push it through. Bob is now your uncle.

BL

[bmeryman]

Great tips here! I'll have to save this thread for when I have inevitable problems with this again. Last time (when I didn't try a few of these tips) I just used the cable which was very frustrating.

On another note, would it be safe to assume that Bob Loblaw has a Law Blog?

[Sam in VA]

My early 90's Colorado II has, as others have mentioned, housing stops on either end and an internal tube for the cable only. Another bike (euro Lemond) has a full length tube for the housing. One of my wife's bikes just has a hole at either end of the top tube. For this, I use brake cable that has a slight bend at one end that I keep oriented upwards. The upward helps to locate the hole on the other end, but it still takes a while. Once through, I slide the housing over the cable and use it as a guide to pull the housing through.

[uno-speedo]

Good job on threading it through.

On an aluminum Klein mtn bike frame, I put a slight bend in the end of the cable and thread through the frame and tease it out with a magnet.