Topic: CB 650 Brake Calipers

[Wayfarer]

There are two bolts that hold the front brake calipers of a 1981 CB650C together.  I don't mean the two that mount them to the forks, these hold the 3 pieces of the calipers together.  One of them has a rubber grommet type thing on it, in a recessed area of the bolt so that it's OD is flush with the OD of the bolt.  Both calipers I removed from this bike have this grommet thingy on just one of the two bolts, so I'm assuming its by design.

What is the purpose of it (optional) and, more importantly, in which of the two caliper bolt holes does it belong?

TIA,
Tim

[Robert]

The manual sayz: "The upper caliper bolt has a rubber seal and is identified by the word "upper" on the bolt head".
I guess it's a rain/dust/whatever seal.

[Wayfarer]

The manual sayz: "The upper caliper bolt has a rubber seal and is identified by the word "upper" on the bolt head".
I guess it's a rain/dust/whatever seal.

Thanks!  Serves me right for buying an aftermarket manual.

Tim

[Terry in Australia]

Because they're single piston calipers, they have to slide sideways when the brakes are applied, the two bolts have a good smearing of grease to stop them seizing in the caliper body (electrolysis) and the seals on each bolt are to stop the ingress of water and dust, and the egress of grease all over your discs. The rubber sleeve on one bolt is to stop the suckers rattling. Cheers, Terry.