Occasionally persistent squeel after braking (sram axs disc brake)

I get an occasional persistent squeel after braking as if my pistons don’t fully retract on my bike with sram axs disk brakes. Any way to fix this, can I lubricate the pistons?

It is worth checking and maintaining the pistons. Here is one video on the topic.

On top of that, there could be a heat and/or caliper alignment issue.

  • If the disc rotor is warping a bit under higher heat, it can make regular clearance turn into a rub. This is more common on the older Shimano Road Rotors, but can happen to others as well. If this is happening, it may take a minor but acceptable clearance between the pads in the caliper and push it to a rub.
  • So double-checking the caliper alignment to the rotor is worthwhile. And anytime I look into that, you also want to make sure you have a straight rotor to start. These can be bent unintentionally which will make alignment a tougher task. So make sure the rotor is straight first, then check caliper setup.
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The SRAM manuals repeatedly have this statement:

Do not apply DOT brake fluid or grease to caliper pistons when performing troubleshooting procedures. Use of DOT brake fluid or grease can diminish braking performance and cause rotor rubbing.

So it seems like they don’t want you to lube the pistons. But the phrasing of “when performing troubleshooting” throws me off a little. Can I use DOT fluid to lubricate them if I’m not troubleshooting and simply cleaning and bleeding? Or should that never be used?

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I did the clean as described in the park tool video last week and so far so good


Great to read. :smiley:

I may end up doing it soon for my gravel bike after a soggy race.

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