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Old 08-21-14, 06:48 PM
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rm -rf
don't try this at home.
 
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Warnings for Internally routed brake cables

My Orbea has an internal rear brake cable. I just assumed I could pull the old cable and the new one would follow the channel. NOT!

There's a thin plastic tube just slightly larger than the metal cable. It's not secured to each frame hole at all. So when I pulled out the cable, the end toward the headset fell down away from the cable hole. I removed the fork and headset and could see it, but had no idea how to fix it.

The LBS mechanic did it a couple of minutes. I think he fished new thin plastic tubing from the back end toward the headset, and guided the housing back out the front hole with his fingers. (The fork was already removed, and his fingers could reach the front brake hole.) I got the frame back with a couple of feet of plastic tubing hanging out each end.

I simply fed the new brake cable into the tubing, all the way out the back end of the frame. Then I slid the front end of the housing down into the frame about an inch, and carefully trimmed off the excess at the back, without nicking the metal cable inside the housing. I cut part way through the housing, then twisted it to break it apart.

The video below implies that they just pull out the thin tubing after fishing the new wire through, and set it aside. Since there was resistance when I pulled on the original thin housing from the back, I think my frame has some internal foam or plastic rubbing against the cable. And it had the housing on the cable already, so I kept the new housing in there, too.

So now the thin housing just floats free within the frame. The normal heavy outside brake cable housing has housing end covers and fits into sockets in the frame, and those sockets have tiny holes just big enough for the thin internal housing.


Next time, To replace a cable the easy way:

Remove the heavy outside housing from the frame to the back brake. Now there's 8-10 inches of bare metal cable at the back of the bike frame.

Get a new piece of thin internal tubing, at least 12 inches longer than the internal frame distance, so it will hang out both ends.

---If you had a section of thin tubing around the cable inside the frame:
Slide the new tubing onto the end of the cable, to butt against the current internal tubing.

Now you can "carefully" push on the new tubing while you pull the metal cable from the front end. Keep feeding the new housing with a little pressure so it stays on the brake cable as you slowly pull the cable out from the front. Eventually, you'll see the front end of the new housing, still on the last 8 inches of the brake cable. Pull it through enough so it won't fall back in.

---If there's no thin internal tubing, just an internal brake wire:
You can simply slide the new tubing onto the old wire cable, all the way out the hole in the front of the frame. Pull out the old brake cable, holding onto the tubing. Push the new cable wire through the tubing and out the back frame hole, then pull the tubing out. Slide the rear section of housing onto the wire, and clamp onto the brake.

Easy, once you know the trick!

----Video example ----
See the 0:50 to 1:10 section of this video. It shows the thin tubing, but kind of skips over actually fishing it back through along with the old brake cable.

I didn't find the rest of the video very useful. A spoke hook tool wouldn't fit through the frame hole on my Orbea at all--the hole is no bigger than the width of the thin tubing!


The tubing looks like this:
Attached Images

Last edited by rm -rf; 10-13-18 at 08:01 AM.
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