Brembo Rear Brake Master Cylinder

[David S]

The Brembo Rear Brake Master Cylinder has two drillings in the base of the reservoir; one is 2.5mm dia (approx.) and passes straight through to the cylinder the other is about 5mm aft  and starts off at about 2.5mm but looks as if it reduces down to a pin hole size.

Should this also connect through to the cylinder?

If this is the case I'll need to unblock mine. If not, what is it?

DWS

[Miti]

Hi David;

The smaller hole is the fluid return hole.  It's often described as the 'spooge' hole (especially by our American friends).

If this hole blocks, the pressure created by the piston has no way to 'bleed away' and when the brake is applied, the pads clamp themselves to the disk...  It can also cause the bake to bind and 'lock on' in use (this happened to me on a VF750 Honda).

The diameter of the hole is tiny.  You'll probably find that a very fine strand of wire will just pass through. (see link I embedded above)

Hope that helps

BR

Jeff

[David S]

Jeff,

Many thanks; that all makes sense.

DWS