Bleed block spacer for Shimano brake caliper with lazy piston

If you encounter uneven pressure from your bike brake caliper, it's probably because of a "lazy piston". The most common cause is a dirt buildup around the seal/piston and most of the time you can easily solve this matter by carefully cleaning it with break cleaner or alcohol 95/99%.

The design is inspired by the Shimano Shimano Bleed Spacer reference Y8N219000 for the DURA ACE/ULTEGRA/105/GRX brake caliper.

Instructions

Insert the brake bleed block spacer, and press the brake lever until the piston reach it's final course. Carefully clean around the piston with a small non scratching brush and some brake cleaner or alcohol. Push back the piston (Careful, always keep the oil screw open on your brake handle to not damage the inside seal).

Turn the block around and repeat the operation on the other side. Once they're both clean, test your brake to see if the pressure is equal on both side. Repeat operation if needed.

Printing

Print flat or standing up or even at 45° angle, as you please. Support recommended. Infill 30% should be enough in strength to handle the pressure from the caliper but you can go higher if you want. 0.2mm layer height is perfectly fine. PLA is more than enough for this.

2 models available, one similar to the manufacturer that can be inserted from the bottom and a longer version without the wings that can be inserted either from the top or bottom

Compatibility

It should be compatible with the following model of Shimano DURA ACE/ULTEGRA/105/GRX Brake Caliper flat mount : 

• BR-R9170

• BR-R8070

• BR-R7070

• BR-4770

• BR-RX810

• BR-RX400

• BR-U5000

• BR-RS805

• BR-RS505

• BR-RS405

• BR-M9100

• BR-M9110-R

• BR-M8110-R

• BR-M7110-R