I’d got the horrible howl on the brakes of my singlespeed. Replaced the pads, bedded them in – all quiet for one ride and then it came back. Tried sanding the pads, cleaning them etc etc. No joy. As a result I’d given up riding it, which is a shame as it’s my only mtb and I do like it. Anyway I got inspired to have another crack at it. Bought a can of brake cleaner spray from Screwfix (£3 odd) cleaned the calipers up with a good old soaking and wipe down. Dug out a couple of pairs of already rejected pad and held them over the gas ring until thoroughly heated, then gave them a good sand down with rough sandpaper. Gave them a try up and down the street and … they were fine! I couldn’t quite believe it so I went out for a ten mile spin last night and they were still fine. Wahey!
It might not seem like a big deal I suppose but it is for me. I get to ride a bike that gives me pleasure after a long lay off. A small victory in life.

FNM

Ee, I’ve missed this. Had a lovely dry, dusty (!) ride on the SS. A deer vaulted a fence in front of me and two curlew flew overhead. Mindfulness and cadence. #SummerOfSinglespeed pic.twitter.com/1K4cRTWB7Q

— Mr Sparkle (@darwendashers) June 13, 2022

Maybe on the next ride the squeal will return 🤔😂.
The oil leak won’t have gone away but the pads have been decontaminated for now.

Yeah, maybe. But at least I can tackle it if it does.

The oil leak won’t have gone away but the pads have been decontaminated for now.

This has possibly been solved.

Shimano brakes are known for some having micro leaks, and it was assumed they were coming from around the pistons. But what has been found is it is coming from the oil transfer port that allows the fluid to move from one caliper 1/2 to the other, and by replacing the ‘o’ ring that should seal that port, the problem may be solved.

Are these o-rings easily obtainable?
Do you have a link to a supplier?

I’ve bought some from simply bearings  – replaced the stock nitrile 70 ones with nitrile 90 so they don’t leak. 1.5cross section x 3mm internal dia. Caveat – I’ve not fitted them yet 🙂

https://simplybearings.co.uk/shop/Seals-O-Ring-Seals-NITRILE-O-Rings/c19_4501_4705/index.html?selection=Nitrile+Rubber+O-Rings

Thanks.
That thread title put a great big smile on my face.
Back to the nuts and bolts of mtb and a million miles away from all the worries of the world.

Shimano brakes are known for some having micro leaks, and it was assumed they were coming from around the pistons. But what has been found is it is coming from the oil transfer port that allows the fluid to move from one caliper 1/2 to the other, and by replacing the ‘o’ ring that should seal that port, the problem may be solved.

Very interesting!

Tried sanding the pads

I did this for the first time the other day after firing latex all over the discs having assumed (wrongly) that my new wheels were taped for tubeless. Turns out they weren’t and with using a compressor to inflate the tyres to 60 psi, I had latex firing out of every spoke hole before I realised my mistake.

So I ended up having to sand it all off!

[url=https://flic.kr/p/2nrA2Yw]Sanding brake pads[/url] by Ben Freeman, on Flickr

wouldn’t it have been easier to take the pads out of the caliper? 🤣

Very interesting!

Indeed, but this is 3rd maybe 4rth hand info. And for the life of me I cant remember where the thread is I saw it only that it linked to a different forum and i pretty much scanned the info.

As with Barney’s post  -“1.5cross section x 3mm internal dia.” thats the info that was on the thread as to the size, but there was also a pic showing a shimano o ring, which was flattened on top(rather than a full round profile), and the user had replaced that with a standard o ring. They got it in one of those 100 piece kits of all sizes, as seen on ebay/aldi etc

Although I cannot vouch for this being a fix, it does hit home that such an assumption as to how and why could well be correct. The person posting the info seemed to have made a study of it at least.

I’ve also got a duff caliper(Shimano 510) and as im intending on swoping them for V4’s when i do that I’ll strip the shimano caliper and see if i can sort it using the info on that thread(Im still looking for it. Pretty sure it was one of the Ebike forums im on)