Zero front Brake Pressure | Page 4 | GTAMotorcycle.com

Zero front Brake Pressure

Priller

Well-known member
I guess I can do the reverse method again. But i may need another bottle of fluid to get going again.

Even at $25 for the good stuff, it's worth it. Considering the struggles you've had so far, I'd be worried about the stuff you had starting to pick up some moisture from the air anyway. Not sure if that's a real risk, but I know DOT4 can be quite hygroscopic, so if the bottle has been open and the fluid pumped back and forth over a few weeks, it may not be ideal for a sportbike.
 

Wyled

Well-known member
Even at $25 for the good stuff, it's worth it. Considering the struggles you've had so far, I'd be worried about the stuff you had starting to pick up some moisture from the air anyway. Not sure if that's a real risk, but I know DOT4 can be quite hygroscopic, so if the bottle has been open and the fluid pumped back and forth over a few weeks, it may not be ideal for a sportbike.
Yeah my thoughts exactly.
 

Trials

Well-known member
Bad brake fluid doesn't care what kind of motorcycle you ride, if there is sufficient water content in the fluid and your brakes heat that fluid to boiling point 100+C
:geek: you are making steam and air bubbles are a component of that process.
 

PrivatePilot

Ironus Butticus
Site Supporter
don't you have that backwards, I can't work on a car or truck brake and operate the brake pedal at the same time, but I sure can do that on a motorcycle brake, especially if the entire brake system is off the bike and in my hand.
and holy your brake master cylinder only squirts a tiny bit of fluid with each pump, how many times did you pump it for the reservoir to go dry.

If you can pump a vacuum bleeder by hand, also pump the brake lever by hand, while also pouring in more brake fluid while it potentially rapidly depletes at the master cylinder depending on how much vacuum you're pulling at the same time, all while cracking the bleeder open and closed during the process, well, let me know as I'd like to watch - that's some serious Ganesh level **** going on.
 

Trials

Well-known member
repeat, I do not use a vacuum bleeder. there is plenty of gravity where I live plus I have a hydraulic cylinder in the form of a master cylinder at the top and a syringe that makes a dandy hydraulic cylinder full of fluid at the bottom, neither of which I would ever want to operate at the same time :unsure: have you bled motorcycle brakes before?

... put a bleed nipple at the high point in that system and you'd have somewhere to use your vacuum pump to suck the air bubbles out of it.
 

PrivatePilot

Ironus Butticus
Site Supporter
repeat, I do not use a vacuum bleeder. there is plenty of gravity where I live plus I have a hydraulic cylinder in the form of a master cylinder at the top and a syringe that makes a dandy hydraulic cylinder full of fluid at the bottom

Glad you've had universally great experiences bleeding brakes.

If it was always so easy we wouldn't all be discussing this nightmare scenario the OP finds himself in though, would we? I've also been there having fought with the front brakes on my old VTX when I had to replace the master cylinder as well.

Hey, have you ever seen and experienced some of the new high tech bikes with multiple callipers, ABS modules, anti dive systems, proportion valves, etc? Not everyone rides a trials bike with a Go-Cart level braking system.
 

Trials

Well-known member
*** no I learned the hard way decades ago!
but now it takes minutes with no mess.
and no I don't have ABS motorcycles and neither is his.
don't want one either.

and PP, trials bikes come fitted with the most advanced brake components in the industry.
 

Priller

Well-known member
Bad brake fluid doesn't care what kind of motorcycle you ride, if there is sufficient water content in the fluid and your brakes heat that fluid to boiling point 100+C
:geek: you are making steam and air bubbles are a component of that process.
This is definitely true, but my understanding is that if you have a small amount of water, you're much more likely to experience brake fade when using them hard somewhere like a track vs coasting to a stop at lights...
 

Trials

Well-known member
This is definitely true, but my understanding is that if you have a small amount of water, you're much more likely to experience brake fade when using them hard somewhere like a track vs coasting to a stop at lights...
Bloody right, it can cause your rear brake to drag and you not notice it for a while if you are on a powerful street bike too.
... until it is glowing red hot.

Symptom is: you ride, brakes are good, bike develops mushy brake and drags, you bleed it and it is fine until the next time it gets hot,
and you need to bleed it again. ( I call it the worlds smallest steam engine effect )
 

J_F

Well-known member
Site Supporter
^ so the steam forces the pads out and they drag?
even when you're off the brakes?
interesting
 

Trials

Well-known member
^ so the steam forces the pads out and they drag?
even when you're off the brakes?
interesting
When water boils it makes bubbles.
:geek: I can prove it too.
 
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Mad Mike

Well-known member
this might be a dumb question but oes you master have a bleed circuit? If so it gets bled first.

My 09 GSXR had a bleed circuit at the master.
 

Trials

Well-known member
H20 is comprised of hydrogen and oxygen.
Stare at this for a few hours @J_F :LOL: you'll figure it out.

 
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Trials

Well-known member
what a strange little man you are :|
 

Wyled

Well-known member
If you can pump a vacuum bleeder by hand, also pump the brake lever by hand, while also pouring in more brake fluid while it potentially rapidly depletes at the master cylinder depending on how much vacuum you're pulling at the same time, all while cracking the bleeder open and closed during the process, well, let me know as I'd like to watch - that's some serious Ganesh level **** going on.
Yeah what I've been doing is pump to 25 mercury to get a nice vac, drop it fast, crack the bleed, pumpng the handle with my left, grab the vacuum go at it, as soon as it depletes, drop the vacuum, close it and fill.
 

Wyled

Well-known member
Bad brake fluid doesn't care what kind of motorcycle you ride, if there is sufficient water content in the fluid and your brakes heat that fluid to boiling point 100+C
:geek: you are making steam and air bubbles are a component of that process.
Does it matter what my boiling point is listed at as wet? I have a wet one of 410farenheit
 

Wyled

Well-known member
this might be a dumb question but oes you master have a bleed circuit? If so it gets bled first.

My 09 GSXR had a bleed circuit at the master.
Thanks Mad Mike yeah it does. I tried doing so like that, but to no avail
 

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