Bleeding brake lines, is there a right or wrong way to do it? | Page 2 | GTAMotorcycle.com

Bleeding brake lines, is there a right or wrong way to do it?

kellen said:
That's how I do it too
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Same way I did it on all my cars, was pump 5 times..hold.. open bleeder, and the pedal would go down. close bleeder and repeat.
Just wasn't sure if the same procedure was for bikes too.
 
From experience, I would add that rear brakes are often the hardest to bleed. I have found that you do the open, pump and close described above until it stops making any difference. The extra advice is stop and let the whole mess sit for a few hours and then come back to it. For some reason the extra time makes all the difference on a rear master that doesn't want to bleed out all the air. parillaguy
 
One possible incorect way of bleeding brakes is to use full strokes of the brake handle when pumping. Some MCs, like older Brembos, will cause failure of the piston seal if you use full stokes. For these, it's better to use shorter strokes to pump fluid through the system.

Also, to expel the last air bubbles out of the front brakes, a trick is to tilt the front wheel to the left and tie the brake handle to the grip with an elastic cord. Leave this overnight. All the remaining bubbles will be forced out of the system and the handle should be solid. This works well for non-ABS systems; ABS systems are different.
 
+1 for hose on bleeder like spray posted. No messing around with opening and closing repeatedly. I flush my car brakes once a year like that since it's so convenient. Also it worked way better on my bicycle than ******* around with pushing fluid up with a syringe.
 
There's a way to gravity bleed. A certain technique will let the fluid run straight through like a girl on her period.
Buy me beer & I'll show you.
This comes in handy if you're doing your car & you don't have another guy.

If you got air in your front master cylinder it might be easier to suck the air from the nipple at the top.

With vacuum method, to remove stubborn bubbles you gotta pump really fast. If you're pumping you gotta pump pretty hard.



*I know that's what she said *
 
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Gravity bleeding is ineffective unless there's a straight up-down path for the fluid to drain, with no nooks and crannies for air to hide. Most brakes have high points in the system that can trap air or old fluid (like one of the brake pistons being above the brake line connection on the caliper).

The pumping action creates a jet of brake fluid in the system that causes something like a foaming action where there are pockets of air. That foam is then pushed through bleeder because it's drawn into the stream of brake fluid (I think of it like the air being sucked out of a car when a window is open on the highway).

That's why the pumping action before opening the bleeder can be more effective, it foams up whatever air is in there a little faster than the open-squeeze-close method. Though the open-squeeze-close method is much more effective at filling the brake system with fluid when it's completely empty.

The STG guys did it textbook AFAIC. Except for leaving some air space in the reservoir. I think that'll only cause the fluid to contaminate faster. There's a rubber 'pocket' in the cap that allows for expansion of the fluid even with no air in the reservoir.
 
"This works well for non-ABS systems; ABS systems are different."
How are ABS systems diffrent?????

Sent from my SGH-I727R using Tapatalk 2
 
fastar1 said:
Gravity bleeding is ineffective unless there's a straight up-down path for the fluid to drain, with no nooks and crannies for air to hide. Most brakes have high points in the system that can trap air or old fluid (.
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Yes gravity bleeding is only for systems without air. You're supposed to keep an eye on the reservoir in the first place.

When you get air in an abs system it's a nightmare
 
Xrayhonda said:
How are ABS systems different?????
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ABS have lines from the MC to the modulators, and again from the modulators to the calipers. The elastic trick might work for the MC-modulator branch, but will not expel air bubbles from the modulator-caliper branches. Pressure bleeding is probably the best method for ABS, based on what I've read. Both of my bikes are non-ABS so I don't have experience with ABS.
 
RockerGuy said:
Yes gravity bleeding is only for systems without air. You're supposed to keep an eye on the reservoir in the first place.

When you get air in an abs system it's a nightmare
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Where air pockets can 'hide', old fluid can hide. Old fluid has air in it. So either way, it's still air stuck in the system.
 
dricked said:
Yep. Why make **** so complicated? Because GTAM.
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I've had great results doing this and over night zip tie the lever closed, next morning crack the bleeder and few more come out


This used to be my signature, but Paulo didn't like it.
 
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