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Check your Shimano GRX brakes

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Check your Shimano GRX brakes

Old 11-07-20, 02:17 PM
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gus6464
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Check your Shimano GRX brakes

My GRX 800 calipers have had a super slow oil leak since I installed them and got tired of it and took it to my shop and they said the leak is from the pistons. Apparently this has been an issue with the first batch of GRX800 calipers out of Shimano. No biggie though as Shimano is just replacing them no questions asked. So as a PSA check your calipers if you have them for any sign of oil.
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Old 11-09-20, 09:28 AM
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Chi_Z
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this applies to every Shimano caliper, I have had 2 DA and 1 ultegra caliper replaced for piston leaks, the easiest way to check is see if you have an oil ring behind the brake pads
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Old 11-09-20, 01:43 PM
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I don't see any signs of oil, but strangely my front brake bottoms out from time to time. I can pump it back up to get pressure again, but something is wrong. I had a shop bleed the brakes, but didn't fix it at all.
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Old 11-09-20, 02:39 PM
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gus6464
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Originally Posted by chas58 View Post
I don't see any signs of oil, but strangely my front brake bottoms out from time to time. I can pump it back up to get pressure again, but something is wrong. I had a shop bleed the brakes, but didn't fix it at all.
Yes so my shop just called me back and my left shifter is also being replaced by shimano because of that same exact issue. The shifter after a while would lose pressure and it's because the seals in the master cylinder are shot.

They said Shimano is not arguing anything and is sending them everything as they currently have grx parts in stock in the US warehouse. I would go back to the shop and have them check it and call Shimano.
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Old 11-10-20, 08:42 PM
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Originally Posted by gus6464 View Post
Yes so my shop just called me back and my left shifter is also being replaced by shimano because of that same exact issue. The shifter after a while would lose pressure and it's because the seals in the master cylinder are shot.

They said Shimano is not arguing anything and is sending them everything as they currently have grx parts in stock in the US warehouse. I would go back to the shop and have them check it and call Shimano.
That's the surprising part of this thread.
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