I like to perform my own bicycle mechanical maintenance, both to save money and because I really enjoy it. I have been doing my own mechanics on both my road and MTB for a decade so I have some experience - most of it very good..........
However, back in early Oct '18 I commenced a Yeti SB6c frame build. I purchased a pair of new XTR 9000 series brakes. I also purchased a pair of Shimano Ice Tech rotors for the build.
My problem with the rear brake is now truly epic. I've put together 3 other hydraulic brakes MTB's before this build - no problems with anything before, a bit of brake squeal to begin with but after some braking runs all runs as it should. Occasionally I've had to sand back a pair of pads but nothing like the current issues I'm having.
I've put in so much work and ridden up my local steep hill so many times now that I'm just jacked off with the entire thing.
The initial build was with Ice Tech rotors - front brake no problem - rear brake shocking squeal - mega decibels like none I've heard before - really loud stuff.
So I have done the following over the past 3 months :-
Emptied the rear brake line and replaced with brand new mineral oil - bled it out for 45 min then left it over night to bleed out the last bubbles.
Cleaned the entire caliper and rotor with brake cleaner
Replaced the OEM resin pads with brand new Shimano resin pads
Performed multiple bedding in runs on the new resin pads - no difference
Replaced the resin pads with Shimano metal pads
Performed even more bedding runs - no difference
Replaced the caliper mounting bolts
Bled the entire line out overnight again
Ditched the Ice Tech rotors and replaced with standard solid steel Shimano rotors
Re performed endless bedding in runs with both resin and metal pads - still nothing
Re-bled the line out again overnight
Cleaned the piston to pad interface with brake cleaner
Re- tensioned the rotor mount bolts
More bedding in runs - endless bedding in runs maybe 100+ brake actuations over 2 weeks down a steep hill ........... then ride back up to the top for another seemingly idiotic attempt
Gave up altogether and took it to my local bike shop - he had it for 2 weeks - I picked it up last Friday - no fix, no ideas and luckily no charge.
The rear brake actually works quite well, has stopping power and good lever feeling but the noise is absolutely horrendous to the point where I've received multiple complaints from local residents about my bedding in runs down the local hill. I just can't keep on going bedding in runs there has got to be something more to it than simply pad/rotor interface issues.
Am I right to be seriously considering ditching the rear caliper in favour of a new one? I'm thinking I must have a dud caliper as I can't think of anything else to eliminate.
I HATE being beaten by this sort of thing. I've invested dozens of hours into this one issue and have made a pariah of myself to some of the local residents. The Yeti is something I've always wanted but it's just so disappointing to have it virtually unrideable still after all this time...........
Bookmarks