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Currently I have a cyclocross bike with Tektro Lyra mechanical cable actuated disc brakes with 160mm wave rotors.

I have had issues with the brakes for some time now, mainly my fault, I accidently put some oil on the rear brakes so they almost stopped working (it was a while ago now). After properly cleaning them they seem to just slip so I ordered new brake pads.

The current problem is not the pads or oil; it's the actual cable and braking mechanism (in my opinion): when I try to brake, the cable and lever are not tight enough, but when I tighten them it becomes really hard to pull the lever. Then I checked the brakes, and compared to the front brakes, they do not 'restore' to same place - when I brake, the lever is hard to press, but then afterwards the cable does not go back to its initial place for some time. The front brakes are super easy to pull, brake fast and restore to initial position almost instantly.

What could this be? I know it's hard to explain, but it seems like the cable is moving back really slowly, and the mechanism in the rear brakes that is supposed to snap back is not as effective.

Should I just take the bike to be repaired?

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My guess would be the cable is old. The inner cable begins to seize or bind with the outer cable. This could be caused by corrosion caused by water ingress over time or dirt ingress over time.

The binding basically causes more friction along the line of the cable - eventually preventing a smooth return to the "Off" position on the brake lever.

You can do a "bodge" and that would be to squirt something like WD40 down the cable line to free it up. But this is only a temporary fix. The proper fix is to install some quality pre-lubed cables which are also weather sealed.

Incidentally, pads contaminated with oil can be cleaned by removing the pads and heating the pads over a flame to burn off the oil.

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    If a bike is not stored outdoors, and the cable routing is not sucky (like some kiddie bikes with the spin-around front wheel) then the cable should not bind due to corrosion for 10 years or more. And if lube is required then something closer to Tri-Flow would be a better choice. – Daniel R Hicks Nov 29 '16 at 12:21
  • That might be it. Bike is 1 year old and is usually stored indoors, however I bike during the rain quite often. – nerijusgood Nov 30 '16 at 13:15
  • WD40 down the cable to help disperse any moisture and then follow it with decent lube. Maybe something like a wax based lube to avoid attracting grit and dirt. But as said above - long term - use weather sealed pre-lubed cable. – OraNob Nov 30 '16 at 14:09

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