I've always been happy with how quiet my SLX 675 brakes are, I use resin pads.
Lately the front has started howling like a banshee, I swapped pads & all good for a bit, but then it returns.
I'd used disc cleaner during the howl process, so will have cleared any obvious residue from a leak.
I've heard about Shimano calipers leaking, mine are probably around 3 years old, is this typical symptoms? Do you get to see oil in the caliper / on the pads, or is it a more subtle leak that contaminates leaving little obvious signs?
I can't keep fitting new pads!
Cheers.
Howling brakes that squawk and judder as you roll to a stop are contaminated with oil or brake fluid.
Try putting the contaminated pads in the dishwasher, which is extremely hot and caustic for efficient degreasing.
My money's on leaky caliper. Both my road ones did this and both times it was the caliper. New caliper under warranty and pads sorted it.
Yea, there's the judder too.
I'm not aware of contaminating them
If it is the caliper leaking, should I expect to see oil seepage? or can it creep more unnoticed round onto the pad?
Brake fluid is very, er, fluid and a little goes a long way.
When mine leaked there were very little obvious signs of a leak. Well apart from the noise and lack of stopping power. Only thing I noticed was the metal back of the pad felt slightly oily.
It can be obvious or not so obvious. One of mine that leaked you can see the fluid bubble around the piston. The others there was no glaringly obvious leak other than the symptoms you describe.
Found it... looks like the bleed nipple has been leaking. I bled them a while back using the Syndicate down only method, maybe something went wrong there. Caliper covered in oily grime. Nipple appears tight. Guessing it's the nipple O ring that's probably not available as a service item.?!
Another differential is that surplus oil that was residing inside the bleed nipple hollow has migrated out and around the caliper & onto the pads. I cleared it out with a 1.5mm Allen key and cleaned with alcohol. I might try another set of pads and see how it goes.....
Probably is a service item but a good hardware store or bearing stockist ought to have the full range of O rings in stock. Or even your LBS, who knows?