Author Topic: Brakes not releasing  (Read 393 times)

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Offline Vincent

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Brakes not releasing
« on: February 07, 2018, 01:07:13 PM »
Hi Guys

Every now and then, after I had to stop, the brakes won't release entirely....

Any idea why? Disc maybe need replacing as it's become too worn?

It's a Yamaha Nitro...
  • Yamaha XT 550 / Yamaha Nitro 100cc


Offline blujeenz

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Re: Brakes not releasing
« Reply #1 on: February 07, 2018, 02:16:15 PM »
Usually the pistons in the calipers need an overhaul as they are responsible for press and release on the pads.

Offline Mat1998

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Re: Brakes not releasing
« Reply #2 on: February 08, 2018, 05:19:27 PM »
Could be the calipers, but have you checked the brake fluid levels?


Offline Vincent

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Re: Brakes not releasing
« Reply #3 on: February 09, 2018, 09:33:32 AM »
Could be the calipers, but have you checked the brake fluid levels?
Will check it this weekend, but last time I checked, it was fine......
  • Yamaha XT 550 / Yamaha Nitro 100cc

Offline Stanthescooterman

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Re: Brakes not releasing
« Reply #4 on: February 09, 2018, 09:47:14 AM »
the brakes won't release entirely....

Front or rear?
Previous bikes & scooters:
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Gilera Runner 180,
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Honda CBX550FII,
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Offline Vincent

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Re: Brakes not releasing
« Reply #5 on: February 09, 2018, 12:55:35 PM »
  • Yamaha XT 550 / Yamaha Nitro 100cc

Offline Stanthescooterman

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Re: Brakes not releasing
« Reply #6 on: February 09, 2018, 01:03:14 PM »
Moisture gets into the brake caliper's dust seal grooves (and sometimes even the fluid seal), over years, causing oxidation of the aluminium, which forces the seal against the piston, causing the pads not to release.

You need to remove the caliper, pop the pads & the piston out, carefully remove the seals, scrape out and clean out the grooves nicely, reassemble and bleed the brake line.

This should solve your problem.

Budget about 1-2 hours' labour.
Previous bikes & scooters:
BMW C600 Sport
Kymco Grand Dink 250 (300),
BMW F650GS Dakar,
Gilera Runner 180,
Kymco Agility 125,
Kymco TB100,
Kymco Heroism KH125,
Honda CBX550FII,
Suzuki RG50 Gamma

Offline Vincent

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Re: Brakes not releasing
« Reply #7 on: March 16, 2018, 08:42:18 AM »
Could be the calipers, but have you checked the brake fluid levels?
Will check it this weekend, but last time I checked, it was fine......
Hey Matt and Stan!

Well, finally took the caliper off, and took it apart. Then couldn't get the pistons out!

So reassembled, and replaced brake fluid, AND MADE SURE IT WAS NOT FULL.

The problem appears to be gone, so must have been too little brake fluid!   :rules:
  • Yamaha XT 550 / Yamaha Nitro 100cc