O ring for fixing l...
 

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[Closed] O ring for fixing leaky shimano calipers

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Posts: 143
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Okay, the last thread I could find about this was 3 years ago and the link in it was dead...

So. In an attempt to remedy the micro-leaking that I think my daughter's brakes are suffering from, I'm after some o-rings for the fluid transfer port, as (somewhat nebulously) mentioned here:

http://blueliquidlabs.com/repairs/solving-that-brake-squeal/

Mr Blue Liquid Labs doesn't give a link, or an indication as to how easy they are to source (and in any case, he's in he US), and only provides a photo.

The only info I could get from that were that they were 3x1.5 with a Buna 90 (?) durometer. There is clearly a measurement missing, mind you. Probably an outside diameter.

Given this rather sparse intel, anyone know where I might be able to get some in the UK?


 
Posted : 18/05/2022 2:21 pm
Posts: 452
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There's nothing missing, o rings are designated by internal dia' x wall dia'. Try these https://simplybearings.co.uk/shop/p20584406/1.5mm-Section-3mm-Bore-NITRILE-90-Rubber-O-Rings/product_info.html


 
Posted : 18/05/2022 2:35 pm
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I’d be interested to know if it works. I seem to remember buying some o-rings ages ago but never fitted them - think I got new brakes and consigned the leaky ones to the spares bin. If it works for you I might just do it!


 
Posted : 18/05/2022 4:33 pm
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I have one of those o ring box from Lidl or Aldi and one of them fitted and fixed a Shimano 785 caliper .


 
Posted : 18/05/2022 4:40 pm
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Thanks for linking this, I will give it a shot.


 
Posted : 18/05/2022 4:49 pm
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I recently bought https://www.ebay.co.uk/itm/141455807147 3mm ID X 1.5mm C/S . Now, I can't remember where I got those measurements...probably a Youtube video, nor have I tried them yet, but worth a punt at £2.68.


 
Posted : 18/05/2022 4:59 pm
Posts: 143
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Fantastic, folks. Thanks very much. Ordered 🙂


 
Posted : 18/05/2022 6:02 pm
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@barney Can you report back once 'fixed' please?


 
Posted : 19/05/2022 8:28 am
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I've had the Shimano brake screech on more than one set of brakes. It wasn't a leak for the fluid port in my case that was causing the issue.

If you're going to the extent of splitting the caliper its easy to check. My leaks were caused by corrosion getting under the main piston seals in the base of the seal groove allowing the oil to find a path out past the seal. The alloy seems to be prone to corrosion. Whilst the outside of the caliper is painted, the paint stops short of the piston recess. If you remove the square edge piston seals it's easy to check. I polished this out with a dremel mop & metal polish.

Before putting the seals back in I put some XCP corrosion inhibitor in the ring grooves. I used the original transfer port O ring along with Loctite 574 flange sealant. Despite getting used on the beach I've had no recurring issues with these.

Good luck.


 
Posted : 19/05/2022 9:00 am
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To add, dirt can also disturb the piston o-rings in the same manner as corrosion can.


 
Posted : 19/05/2022 9:50 am
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I assume we are talking about calipers like these.
null


 
Posted : 19/05/2022 11:58 am

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