Brake Issues - Shimano XT M775

U

ultraben

Squid
Hi all,

Riding home from work this afternoon,half way through the ride, my rear brake started squealing really loudly.
By the time I got home,this had stopped - but I had lost at least half of my braking power.
I can now press the lever on the rear brake down towards the grip with no real resistance.

New to attempting to fix my own bike issues - so after any ideas for things I can look at.

Otherwise,I guess I am off to the LBS:eek:hwell:

Cheers,

Ben
 
Knuckles

Knuckles

Lives under a bridge
Or check to see if you forgot the pad retaining bolt and they've jumped out. Sounds incredibly stupid I know, but.........
 
bootsandall

bootsandall

Likes Dirt
Upgrade time maybe! Sounds similar to a mates issue with his master cyclinder which is at the lever end.

You could try getting a new lever assembly from CRC, http://www.chainreactioncycles.com/au/en/shimano-slx-m675-disc-brake-lever/rp-prod83176

I have found/read on forum post these will bolt straight onto the end barb at the handle bar end, have successfully married old calipers to the newer levers on one of my bikes.

Or whole new brake is only $90 which is most likely what its going to cost for your LBS to look and maybe repair your current brake
 
S

Shadow Puppet

Likes Dirt
I had similar issues. The culprit was the truck/car wash solution I was using. It was contaminating the Shimano pads. I've been using this same solution for years and it has never effected the Formula sintered pads I had but the Shimano pads just don't like it. I put the pads on the BBQ for a bit to burn off the residue and they come back to life good as new. Worth a try before buying a whole new brake set.
 
dunndog

dunndog

Eats Squid
Possibly a bit obvious, but have you checked for a leak at the caliper end? Might explain the squealing as the pads became contaminated, and the loss of power due to either loss of fluid or air entering the system.
 
Ivan

Ivan

Eats Squid
dunndog said:
Possibly a bit obvious, but have you checked for a leak at the caliper end? Might explain the squealing as the pads became contaminated, and the loss of power due to either loss of fluid or air entering the system.
Click to expand...

I believe some XT's had leaking caliper issues, so you could be onto it.
 
U

ultraben

Squid
It poured down pretty heavy for a bit of my ride - so was wondering if something had just splashed up and contaminated the brakes - then I find the lever can now be pressed down without resistance and no real bite on braking.

As advised,tomorrow morning I will check brake pads/whether there is any leak at caliper.

Your collective advice is much appreciated.

Cheers.

Ben
 
U

ultraben

Squid
Hi all,

Checked brake pads and no real noticeable wear - and unable to see any leak from caliper.
The thing that stood out for me is when pressing brake lever - the pistons don't seem to squeeze the brake pads against rotor with any force.
Anyway - that is my non-technical observation.......dunno what it means.

I'm thinking it might be easier and cheaper to visit the LBS!

Cheers.

Ben
 
Johnacles

Johnacles

Likes Bikes
Contamination of either the pad or rotor. First try cleaning pads and rotor (with brake cleaner), if that doesn't work clean the rotor again and sand back and clean the pads once more. If this solution doesn't work, try swapping pads. Again, if that doesn't work and there is no visible leaking from the caliper, it's probably time for a bleed, although it sounds just like contamination. Same thing happened to my TRP Hy/Rd's the other week, new pads fixed it a treat!
 
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