OP
UTC

Member
Vespa, Yamaha
Joined: UTC
Posts: 23
Location: Gainesville, GA
 
Member
Vespa, Yamaha
Joined: UTC
Posts: 23
Location: Gainesville, GA
UTC quote
Doing some maintenance on the new ( to me ) mp3. Some nasty brown brake fluid came out as I flushed the fluid through the rear brakes. Is it normal for the pressure to come back very slowly when bleeding the rear brake? I've got it back to almost normal(after like 200 pumps!), but not as firm as I'd like to feel it. Am I missing something?
Thanks,
Hip
@jimc avatar
UTC

Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 44954
Location: Pleasant Hill, CA
 
Moderaptor
@jimc avatar
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 44954
Location: Pleasant Hill, CA
UTC quote
Just like the front brakes, the rear brakes are most easily bled in reverse, pushing fluid into the nipple and syringing it out of the reservoir. This reduces the chance of 'air-locks' in the brake line as it weaves up and down, and prevents air being sucked in through the nipple threads.

However, persevering with conventional bleeding can eventually get it done, but you have to be quick enough in each operation to prevent any air bubble half way along just gliding back to where it was between pumps.
OP
UTC

Member
Vespa, Yamaha
Joined: UTC
Posts: 23
Location: Gainesville, GA
 
Member
Vespa, Yamaha
Joined: UTC
Posts: 23
Location: Gainesville, GA
UTC quote
Wow! How do I reverse bleed?
UTC

Ossessionato
Scarabeo 500GT(hers), `07 250 MP3, `09 400 MP3
Joined: UTC
Posts: 2592
Location: Kingman, Az.
 
Ossessionato
Scarabeo 500GT(hers), `07 250 MP3, `09 400 MP3
Joined: UTC
Posts: 2592
Location: Kingman, Az.
UTC quote
The few times I flush out old brake fluid, I just put in fresh fluid until all the fluid @ the other end that comes out is clean too and the brake levers operate proper.
@norcal_rider avatar
UTC

Member
MP3 500
Joined: UTC
Posts: 36
Location: Sonoma County, CA
 
Member
@norcal_rider avatar
MP3 500
Joined: UTC
Posts: 36
Location: Sonoma County, CA
UTC quote
My best results with bleeding brakes on any motorcycle have come with using a Mityvac vacuum pump. It's relitively inexpensive and will draw all the old fluid through the system leaving only the good clean stuff behind.
OP
UTC

Member
Vespa, Yamaha
Joined: UTC
Posts: 23
Location: Gainesville, GA
 
Member
Vespa, Yamaha
Joined: UTC
Posts: 23
Location: Gainesville, GA
UTC quote
I used a mityvac and pulled the nasty stuff out. But still had a hard time getting the pressure back up.

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