Modern Vespa

Hi Everyone. I'm finally getting around to changing the brake fluid (manual says every 2 years). The front (right lever) brake system is pretty straight forward. The combined (left lever) is not so clear. Though there is a separate bleed on the front caliper and a bleed on the rear caliper, there is also a bleed in the pneumatic splitter (don't know correct name) (see picture).

The manual says nothing about bleeding through the splitter, but I saw a Scooter West Vespa video that mentioned it needed to be done.

Has anyone else done the brake fluid replacement? Did you bother bleeding the splitter separately? Maybe the bleed on the splitter is just to fill an empty system. It would make sense to me that as long as I'm exchanging the fluid and not letting any air into the system, I should be OK just bleeding the front and rear calipers.

Thanks in advance.

Well, just to follow up. When flushing the left brake system serving both the rear and front caliper, I flushed rear caliper, then front caliper, then the splitter (shown in my previous post). The splitter showed new fluid (it was clear) almost from the start, so I'm not sure if I would spend the time removing the front shield to get to it next time.

I took advantage of having the front shield removed to add a new horn

One other item to note. There are many videos that show flushing using a vacuum (syringe or vacuum pump) on the bleed valve. This works for the rear caliper and the front break (right lever) system, but will not work for the combined (left lever) front or the splitter bleed. Pressure is needed. The old pump break / bleed / repeat worked for these.

Hi Beeg61, as you correctly worked out, no need to touch the brake splitter pressure regulator bleed nipple. It's only really there for initial fill up bleeding to get the air out. Straight forward fluid exchange can be achieved by usual bleed method as laid down in the manual.

And did you notice you have two bleed screws on the front caliper? One is for bleeding the front master cyliner the other if for the back/combined master cyliner, make sure you flush both.

I'm having issues accessing my rear brake bleeder on my bv500 due to the tight space between aibox and brake caliper, any thoughts or tips?

Never bled the brakes on a BV500 but the procedure in the workshop is to always remove anything that is in the way. It may mean just undoing the airbox screws/bolts to push it to one side. The job has to be done and we don't mess about. What does your workshop manual say?

Funny enough I have the full shop manual and it skip right to the part where the brakes are being bled and nothing about body work. Same goes for the front and accessing the master cylinder there, which I had to remove the front cowl for and find the screws.