other than shop service on them they are completely fine, one’s leaking. could this amount to much less braking power that it should be?
by Financial_Option_757
other than shop service on them they are completely fine, one’s leaking. could this amount to much less braking power that it should be?
by Financial_Option_757
3 Comments
Probably someone pushed the pistons in without opening up the bleedport. The diaphragm ruptured. If you lean the bike on that site it will leak faster. The Shimano site doesn’t show a replacement part for the diaphragm but you could try and fit one for an MT200. Fair chance that will work [https://si.shimano.com/en/ev/BL-MT200-4346](https://si.shimano.com/en/ev/BL-MT200-4346) its part 5 on the exploded view that ruptured/now has a little hole.
If the seal on the master cylinder is leaking and its not just leftover fluid from a sloppy bleed then you’ll have to replace. You’ll invariably get air in the lines and wind up with effectively no brake.
Most bicycle hydraulic brakes aren’t rebuildable unfortunately. On the plus side, you can buy an entire replacement front MT420 system for ~€30.
If you can afford it, upgrade to deore xt levers. It’s a pretty simple swap with a bleed kit. Then down the road when it comes time to replace pads and rotors, complete the swap for the full xt system. I just did my levers on my San Quentin and they’re so much nicer paired with the BR-MT420s than the BL-M4100s were