Everyday road bike seems to be plagued by glazed pads/squealing on the front. Swapped out the pads and disc and after one ride it's back again. Can only presume the caliper, Shimano BR-RS785 may have a slight leak.
Do I just bite the bullet and buy a new caliper, or anyone have any tips to fix?
What discs? In my experience the cheaper ones that say 'organic pads only' are very prone to squealing, I've barely had a peep out of my ice-tech ones. Still do get a squeal now and then when it's wet under a hard stop, but it's just once or twice a ride not every single stop.
An Rs785 caliper must be a good few years old now, so yes, I'd go with leakiness. Both mine went a couple of years back - replaced them with deores and its been fine since.
@molgrips wouldn't mind if they were cheap discs but they are RT-CL800's
Those particular early road calipers are notorious for leaking. Bin then. I switched to some cheap XT versions, which have been leak-free and are less prone to squealing (I believe the pads can retract a touch more)
I'm on 105 calipers from 2021.
You have removed two of the three variables (pads and rotors) so, unfortunately, it is probably the calliper leaking. When you remove the pads is there a ring of oil on the back of the pad?
@anguswells - yep confirmed - ring of oil. New caliper time
Thanks all.
Yeah just buy a new caliper - I’ve had a couple of Shimano road calipers do that - one of which is the same model as yours. Either replace with a new Shimano one or the Hope RX4 fits as an alternative replacement. I loved the first RX4 I had but when swapping it over to a new frame - getting another one for the other end I’ve had no end of issues with fiddly setup / bleed / leaking etc. so I’m currently less excited about them as an alternative 🤣
If mine start leaking I'll be trying some of these, works on my ebike so hopefully will on the gravel bike
I was wondering the other day if the 2 pot Magura calipers would work well on Shimano road stis…
Certainly looks to work
I've a pair of 785's that leaked and I replaced with Rx4+'s that....leak.
I've repaired the 785's with eBay O rings and piston seals and they're mint again. The Rx's aren't. I even resorted to the LBS incase of of user stupidity but £180 later, they still leak. To be fair, there's £100 of new discs in there but still. Mine have been back to Hope as well. Sadly, I wouldn't bother again despite my old M4's being the best brake on the planet...
Shimano BR-RS785s? I replaced one caliper, not because of leaking, but poor maintenance and A LOT of use meant the piston seized. Easily found on ebay for ~£50. They're fab brakes so I'd just replace same again if something went wrong. 8 years old now, been bled about twice maybe. They just keep going. And stopping ARF!
I replaced leaky GRX calipers with deore ones after they both started leaking. Been trouble free since, no compatibility issues and the calipers were cheap.
My wife's SLX's used to do it - clean everything, replace pads, and low and behold start squealing and no stopping. Turned out to be where the hose is tightened into the calliper - needed nipping up tight - must have had a fine leak on braking - no such issues since. Bike was second hand !
@fossy That's where the rx4's leak. No amount of nipping/new hoses/new olives etc would sort. In fact, any further nipping will probably result in an advanced state of ****ed up ness. The 785's leaked at the usual transfer port o ring but I changed the piston seals as well as a precaution.
Cheers @boblo - ordered the o-rings, but the piston seals are out of stock, at the moment.
Not in a hurry, though.
@belugabob There's loads of other suppliers, just make sure you get the right sizes 👍
the cheaper ones that say ‘organic pads only’ are very prone to squealing
Interesting, I have the cheap shimano centre lock resin only ones (RT10 I think) and my brakes (Juin Tech R1s), which I'm pretty sure aren't leaking, shriek like a banshee at the slightest hint of moisture - gets heads turning in the thick of the school run.
New rotor time.
Yes, I've found some, just now, thanks.
