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Turns out Clake makes shorter Brembo rear master cylinder inserts than what the Redshift master cylinder uses. I happened to end up with one of them.
If a shorter insert is used in a LHRB kit, the brake fluid pressure would leak past the o-ring and push out the Brembo master cylinder sight glass.
The one on the left is a wrong one at 47mm overall length. The one in the middle is the correct one at 51.5mm overall length. The one on the right is not an insert!
When I started finger-tightening that insert, if bottomed out before I started feeling any resistance that I expected when the O-ring is compressed. This prompted me to stop and measure things.
The master cylinder depth is 43.5mm from the top to the edge on which the O-ring sits. But my insert was only 37mm long. The O-ring cannot possibly fill the 6.5mm gap!
I contacted Clake and they understood the issue, sincerely apologized, and sent me another insert (shown in the middle of the top picture). It is 4.5mm longer. It has a 51.5mm overall length and 41.5mm from the bottom of the cap to the edge on which the O-ring sits. This longer insert compresses the O-ring from its 2.75mm free height down to 2.0mm, good enough to seal off the pressurized brake fluid.
The measured distance shown below should be 41.5mm, not 37mm:
I asked Clake to explain how they happened to have two vastly different lengths for these inserts. Perhaps it is used in another bike, or maybe Brembo uses more than one depth for their rear brake master cylinders. They haven't replied yet, and with the holidays maybe they won't. We'll see, I will update ya'll if they do.
If a shorter insert is used in a LHRB kit, the brake fluid pressure would leak past the o-ring and push out the Brembo master cylinder sight glass.
The one on the left is a wrong one at 47mm overall length. The one in the middle is the correct one at 51.5mm overall length. The one on the right is not an insert!
When I started finger-tightening that insert, if bottomed out before I started feeling any resistance that I expected when the O-ring is compressed. This prompted me to stop and measure things.
The master cylinder depth is 43.5mm from the top to the edge on which the O-ring sits. But my insert was only 37mm long. The O-ring cannot possibly fill the 6.5mm gap!
I contacted Clake and they understood the issue, sincerely apologized, and sent me another insert (shown in the middle of the top picture). It is 4.5mm longer. It has a 51.5mm overall length and 41.5mm from the bottom of the cap to the edge on which the O-ring sits. This longer insert compresses the O-ring from its 2.75mm free height down to 2.0mm, good enough to seal off the pressurized brake fluid.
The measured distance shown below should be 41.5mm, not 37mm:
I asked Clake to explain how they happened to have two vastly different lengths for these inserts. Perhaps it is used in another bike, or maybe Brembo uses more than one depth for their rear brake master cylinders. They haven't replied yet, and with the holidays maybe they won't. We'll see, I will update ya'll if they do.
