Moto-Guzzi Rebuild Update 7

Managed to spend some time in the garage today and ticked off a couple more items on the Guzzi list.

I started out by neatening up the wiring at the battery terminals. There were five or six ring connectors to attach to each terminal and I thought that was a little much. Plus there were some loose wires that just kind of got in the way.

The wires connecting to the battery were two from the bike itself, two additional wires for the sidecar (one for the 12v outlet in the sidecar, one to run the motor for the camber adjustment), an additional heavy gauge wire I ran from the voltage regulator directly to the battery to try and fix the charging issues (didn’t help), the wires from the powerlet port on the side of the bike, and some very tiny wires for the volt meter I added to the handle bars. It was a bit of a mess.

I straightened out the wires, taped a bunch together into a loom, and combined a bunch into single ring terminals. Now there are just three ring terminals to attach to each pole of the battery. Much simpler. No pictures of this work.

The next item on the list was new brake pads in the front. I had already replaced the rear pads when I put the rear wheel on. Replacing the pads is a pretty simple job. I pulled off the calipers one at a time and pried the old pads apart with a screwdriver to push the pistons back into their bores. Then I remounted the calipers with the old pads still installed, since you can install the new ones with the calipers mounted. You just pull the pin and the pads pull out the back.

After replacing both sides it was time to flush the brake fluid. I don’t think this had ever been done. It was black.

Old brake fluid.

I sucked as much fluid out of the rear master cylinder reservoir as I could, then wiped it clean. After refilling it with new DOT 4 fluid I went over to the rear brake. This was my first WTF Brembo moment.

Rear brake caliper.

I mean seriously. How are you supposed to get the air bubbles out if the bleeder is at the bottom? I actually wasn’t too worried about air bubbles but I figured I might get more old fluid out if the bleeder was at the top.

Since I was using a Mighty-Vac vacuum bleeder I didn’t have to pump the brakes to get the fluid to pull through so I could remove the caliper and suspend it with some string so the bleeder was at the top. I pulled fluid through until it was nice and clear and then bolted it back into place.

Then I moved to the front. That’s where I got my second WTF Brembo moment.

Front Calipers

The fluid inlet is right next to the bleeder. How are you supposed to flush the old fluid out of the pistons? Sheesh.

The brakes on this bike are hooked up a little differently. The rear brake pedal operates the rear caliper and the front left caliper (and the sidecar brake.) There is also a proportioning valve of some sort that is attached to the swing arm, so the front/rear balance is affected by the position of the swing arm. The front brake lever only operates the right front caliper.

Anyway, I attached the Mighty-Vac to the front left caliper, pulled some vacuum and cracked open the bleeder. No fluid came out. That’s odd. So I reached across the front of the motor and pressed down on the rear brake pedal (the rear brake pedal is near the front of the foot board instead of being near the center of the motorcycle by the foot pegs – which this bike does not have.) When I pressed on the pedal, all kinds of fluid came out. Also odd, but I can work with this. I ended up doing a combo system of pulling a vacuum and then pressing the pedal. It worked well enough that I was able to get clean fluid out.

Then I moved over to the right front caliper. I had to lower the bike to the floor so I could reach the tiny reservoir on the handle bars. I sucked the fluid out of it and then bled the caliper. This one bled like a normal brake.

So, that’s done, other than the sidecar brake. There is a quick-disconnect in the brake line to the sidecar, so that’s convenient. I’ll have to bleed that caliper after I get the sidecar attached again. Guess I should check the pads then too. Wonder what pads it uses?

I’ll probably want to bleed all the brakes again in the spring, since I’m sure there was old fluid left in all the calipers.

Seriously Brembo, what were you thinking?

1 Comment

  1. I like this trick of pulling the calipers, pry against the old pads to add gap, then reinstall . Much slicker than prying against the new pads.
    Thx for the trick!

    I pulled off the calipers one at a time and pried the old pads apart with a screwdriver to push the pistons back into their bores. Then I remounted the calipers with the old pads still installed, since you can install the new ones with the calipers mounted. You just pull the pin and the pads pull out the back.

Comments are closed.

%d bloggers like this: