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road bike brakes

aderoz2004aderoz2004 Posts: 5
in Workshop
i bought a bike off the internet and the rear brake doesnt fully open and when i start to pull the lever it would just start to engage the brake a second or so after pulling because the first part just pulls in with no resistance not sure what to do antone know what is going on

Posts

  • david7mdavid7m Posts: 636
    Are the pads worn low? Do you have the quick release knob open or closed? It's open to remove wheel easier.
  • webboowebboo Posts: 5,012
    It sounds like the inner cable is dragging on the outer. You might need new cables.
  • aderoz2004aderoz2004 Posts: 5
    i just asked the guy i bought the bike off and he said he had the issue started after he squeezed the calipers together for a cleaning
    could the impact this
  • david7mdavid7m Posts: 636
    Picture? Could be the quick release.
  • aderoz2004aderoz2004 Posts: 5
    https://www.youtube.com/watch?v=2lo1t78FU8Y
    this video shows the problem
  • webboowebboo Posts: 5,012
    Loosen the cable at the caliper. Then see if the caliper springs back when you squeeze it.
    If so the it’s the inner cable dragging, you could try lubricating it. But you probably need to replace it.
    However it the caliper doesn’t spring back then you need ask someone else. :)
  • riceawayriceaway Posts: 8
    aderoz2004 said:

    i bought a bike off the internet and the rear brake doesnt fully open and when i start to pull the lever it would just start to engage the brake a second or so after pulling because the first part just pulls in with no resistance not sure what to do antone know what is going on

    This sounds to me like nothing more than a loose brake cable. Use a 6 (?) mm Allen wrench and loosen the lock screw, pinch the brakes together against the rim and pull the cable tight and then lock the screw down again and see how that is.
  • Charlie_CrokerCharlie_Croker Posts: 1,551
    aderoz2004 said:

    i just asked the guy i bought the bike off and he said he had the issue started after he squeezed the calipers together for a cleaning
    could the impact this

    Assuming your cables are freely moving, it sounds like the two parts of the brake calliper have seized slightly (happens a lot with the rear for some reason). If you pull the two brake pads apart while at the same time pulling the brake lever, does the lever now go back normally? Take them (callipers) apart, clean them, re-assemble them with a little lubricant. Be sure not to over tighten them or you’ll be back to square one – that should do the trick
  • koenkoen Posts: 13
    U should post it here: https://forum.bikeradar.com/categories/workshop that's where people can help u with this problem.
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  • lesfirthlesfirth Posts: 1,356
    This is not rocket science. If you can not sort out what is wrong it could be that you do not have the aptitude for the job. You do not want to find that you have done it wrong when descending at 40 mph.
  • pilot_petepilot_pete Posts: 2,120
    edited January 2020
    lesfirth said:

    This is not rocket science. If you can not sort out what is wrong it could be that you do not have the aptitude for the job. You do not want to find that you have done it wrong when descending at 40 mph.

    Very true. But a bit of logical fault finding should locate the problem:

    1. Undo the cable clamp bolt and free the cable from the caliper.
    2. Squeeze the caliper together with your hand. Does it move freely, or stick as you release it? Try a few times. If it is closing and opening freely then the problem is not the caliper. If the caliper is sticking remove it and check for damage. Strip it and note the order of each component. Thoroughly clean all parts and reassemble with a tiny bit of lubricant on the moving parts. Ensure the caliper now closes and opens by hand freely.
    3. Now, pull the cable through by hand to take up any slack. With the other hand operate the brake lever. Does it pull the cable smoothly? As you release the lever whilst pulling on the other end of the cable does the cable come back out at the caliper end freely? Again, do this a few times to check if their is resistance/ sticking. If there is, then it could be cable inner/ outer damage or a problem with the lever.
    4. If point 3 results in resistance, start by removing the inner cable and fitting a new one. Try again. If this doesn’t sort the problem it may be your outer or the lever.
    5. If the problem still isn’t sorted, check the outer, especially the location where it exits the shifter and any end caps that are fitted where it enters (if it enters) the frame and the caliper. Make sure the ends of the outer have been cut square, the hole that the inner threads through is not flattened or burred and any end caps fitted snugly. If any are found to be at fault and can’t be sorted, fit new outers.
    6. Once you have the cable and lever operating properly and freely and the caliper is doing the same, refit the cable in the clamp bolt, pull the cable through whilst holding the caliper partly closed with one hand (so that the pads are a few mm away from the rim on each side) and clamp the cable. Operate the lever and pull it on hard a few times to take up any slack in end caps etc and then adjust to get the gap/ lever pull and bite point right. Ensure the pads touch the rim symmetrically and if needs be adjust to achieve this. Ensure the cable is clamped to the correct torque and then test on the flat with a run off area before going down hill at 40mph... ;)

    PP
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