Today, I got a new disc for my front Clarks Hyrdaulic brake. Before the change, whenever I pressed my front brake, I could almost do a front flip but that's only if I pressed it fully. Now, when I press it fully, the lever goes all the way down but it feels like the tyre should stop but instead, it goes for slightly longer. It's almost as if there's grease on my brake pads but I know that's not the case.

So my question is, why did replacing the front disc cause my front brake to lose effectiveness? Do I need to wait it out cause it's a new disc or?


2 Answers 2


The disc could be a little smaller, so you need to press your lever further. Normally a hydraulic disc-brake will do a correction on this, but it's worth to re-adjust your brakes.

Most likely, cleaning them will solve the issue. Make sure to clean them correctly. If your pads are greasy, then you might need to replace them. See: What do I clean disk brakes with?

Also, if they are brand-new, you might need to break them in. See user manual for that as brands specify other methods. (Generally you need to do several hard stops).

  • 1
    Disc thickness cannot be the issue - since hydraulic brakes are self adjusting to wear / disc thickness. There is no adjustment that can be made for this - after the first lever pull the adjustment will have been made. If you have changed the disc - make sure the braking track of the disc is compatible with your pads ie. the brake track of your disc has a wide enough brake track - some discs can be a bit narrow, It is worth checking for contamination on the pads or even cleaning the pads as a precautionary measure. Heating on a flame can burn off any oil residue and only takes a minute.
    – OraNob
    Commented Jul 25, 2016 at 11:19

It is most likely that the new rotor and old pads are not bedded in to each other. See this answer for more info. The disc needs a layer of pad dust on it before it will work to it's full potential. It's somewhat similar to getting a new set of brakes.

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