Ducati Hydraulic Work - Sep 2014

I live with two Ducatis. One is an ST2 and the other is an 848 Evo. Both use lots of hydraulics. Both brakes and the clutch on both bikes use hydraulics. Six master cylinders, six calipers, and two clutch slave cylinders.

Here they are. The front right brake caliper on the ST2 seemed to be generating lots more brake dust than the left. I discovered this on my Toursimo North Carolinio. So I decided to do some brake and caliper mainteance. While I was at it, I thought I'd do some hydraulic work on the 848 Evo. I had Duc Pond flush the fluid on the the brakes and the clutch when it was last there. But I didn't like the fact the bike didn't shift as well as the ST2, so I decided to put on a new clutch slave. And while I was in the bleeding business, I'd do the rear brake that Duc Pond didn't do.

On the ST2, the first thing I did was to replace the brake pads. Turns out the left had sintered metal and the right had organic pads. So I put organics in both. The right one continued to generate more dust. That meant I needed to go in deep and take the calipers apart and re-seal them.

First thing I did was to squeeze the pistons out while still connected to the brake line. Once I could get them, I loosened the bolts that hold the two halves of the caliper together. I did this while still connected to the forks (cause I'm a weak girly man and could not hold them tight enough in my hand). Then I disconnected the brake line and brought them over to the bench. I grabbed the pistons with my hands and pulled them straight out. I marked them so I could put them in the same holes.

Here are my new seals (on the left) along with the cleaned calipers. These Brembo 30/34 seals are very difficult to find. They have a beveled edge where the low side must be oriented towards the outside so that the seals push back the fluid on the inside but release the pistons easily into their bores. If they are in upside down, fluid doesn't move the piston and pads - instead it moves past the pistons, doing little to stop the motorcycle.

The seals are in and the pistons reinstalled. Note the tiny o-ring on the top right side of the lower half. That is the passage where fluid goes from one side to the other. That lets all four pistons work at the same time.

All back together and ready for pads and reinstallation. These calipers use pads with two positioning pins along the top. Once installed, I bled the caliper (as well as the other caliper). All in all, a fairly easy job.

This is the Duc 848 with its new Oberon clutch slave cylinder installed and bled. I had to wait to get the silver one, which was the same color as stock (cause I don't like radical color changes). Except maybe for the golden shock resevoir on the TTX36 Mk2 Ohlins shock.

Finally, I bled the rear brake on the Duc 848. Kind of a pain in the rear to add fluid, but by only punching little holes in the fluid bottle seal, I could control the flow.

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