LJR69
Well-Known Member
Doing my monthly check and maintenance of the bikes and I noticed my rear pads on my mtb were unevenly worn and actually almost worn out (in just 3 months). My bike has 4-pot Shimano XT (8120) . Upon removing the pads I was unable to push in two of the 4 pistons (the smaller pistons). I therefore removed the caliper and stripped it down. Upon removing the pistons from the caliper I was met with what you see in the images below - i.e. the back of the pistons had crumbled! I mean how the heck does that even happen, and to both pistons almost identically?!
As the unit is covered under warranty I've fired an email off to Tredz and asked for a replacement. For now though I've cleaned everything up, put the pistons back in, lubed them with mineral oil, put new pads in, refitted the caliper and done a full bleed. The brakes feel absolutely awesome. In my mind the fluid will take up the irregular shape of the rear of the pistons and apply the same pressure - not a long term solution but I feel comfortable enough for it to last me this week at least.
If I never post again I miscalculated. No flowers.
As the unit is covered under warranty I've fired an email off to Tredz and asked for a replacement. For now though I've cleaned everything up, put the pistons back in, lubed them with mineral oil, put new pads in, refitted the caliper and done a full bleed. The brakes feel absolutely awesome. In my mind the fluid will take up the irregular shape of the rear of the pistons and apply the same pressure - not a long term solution but I feel comfortable enough for it to last me this week at least.
If I never post again I miscalculated. No flowers.