How to bleed brake fluid

[Alberto]

Heya guys

Can someone instruct me on how to bleed and refill the brake fluid, what is the process and how to avoid air in the system after the process is done.

My bike has Brembo brakes 2011 TE250

THanks

 

[EricV]

You're gonna find folks who prefer the reverse bleed (from caliper nipple back to the reservoir) but, for me at least, I've found the old conventional way works just fine. As per most manuals:

- Fit a hose to the bleed nipple (ideally w/ the open end submerged into the fluid in a vessel)

- With the bleed nipple still snugged down- apply pressure to the brake lever/pedal.

- Hold lever/pedal down (feeling the pressure), open the nipple slightly and watch fluid escape. DO NOT let reservoir go empty- keep topping it up. You don't want to suck air in on the reservoir end, of course.

- Snug the nipple down and only then release pressure on the lever/pedal.

- Keep repeating these last four steps until you see no air coming out- just clean/new fluid.

It's quick and easy- in fact there's a rhythm you'll get into and it takes no time at all. Kind of fun, in fact. Again there's nothing wrong w/ speed bleeders, but in my exp they haven't really saved me any time (unless you're dealing w/ long lines, like with cars.)

 

[Spice Weasel]

If you didnt already know, wash any spillages off with soapy water when youre finished.
Brake fluid will damage your paint if left on it.

 

[ruwfo]

If you've replaced a brake line & or the master cylinder was completely empty, take the cap of the master & fill it close to the top.
Hopefully you have a bike stand cause it's easier if the bike level, leave the cap off & bleed the brake as EricV wrote.

You'll see bubbles in the master as your doing it, air weight less then the brake fluid so it will always come to the top. Either
when you get NO more bubbles or it gets hard (normal) you can put the cap back on.

My buddy at the bike shop showed me that way & it real easy.

Husky John

 

[Alberto]

excellent guys, thank you for the help on this! I am doing this as preventative maintenance as my bike still has the OEM brake fluid.. so, its time to change it. Almost 2 years with the factory fluid on the brake/clutch

Is it the same procedure for the hydraulic clutch fluid?

 

[Motosportz]

I often times use my vacuum bleeder to do my brakes when wanting to replace all the fluid.

 

[gazmcfaza]

this guy will give you the idea, it's easier to do with the bleeder kit above but it's not essential

View: https://www.youtube.com/watch?v=WcZdqCGBf2E

effectively all you're doing is getting the old fluid down from the master cylinder [on the handlebars] down out the other end, through the caliper, whilst not allowing any air to get in the brake line, take off the master cylinder cap, get a tight piece of hose that squeezes onto the caliper nipple [by the spanner screw bit] then undo it a teeny bit to allow the old fluid to come out into a bottle attached to the tube, squeeze it through whilst keeping an eye on the master cylinder lever [you dont need a buddy] just don't let that lever go so low you allow air to get squeezed in. When you start to see the new fluid [nice clear colour] come through the tube solidly, youre ok to stop, do up that spanner nut then squeeze the lever three more times ish until you feel pressure at the lever, that means the fluid is no longer going out the caliper down the tube but rather into the caliper, behind the seals and your hand is forcing the brake pads against the disc

 

[duggoey]

I often times use my vacuum bleeder to do my brakes when wanting to replace all the fluid.

I have the same unit. It works pretty well but I have found it is a little quicker with two people and minus the pump. I pump the lever and crack the bleed point while another person (wife) keeps the reservior full.

 

[Shovelhead85]

I almost cringe suggesting this super-simple, 2-step, 30 second procedure here, but what the hell...

Okay, here is a semi-cheezy brake fluid change hint that will take only 10% of the time, give you 90% of the beni's... and not introduce any air bubbles that a normal bleed job would: extract all the fluid out of the reservoir; and then put new fluid in. That's it- you're done. If you want to go the extra mile (recommended), after the initial fluid withdrawal, push your brake pistons in (or your brake pads, really) and extract that extra fluid, too... and then refill. The hygroscopic (I think that's the “water ad/absorbing” word) characteristic of brake fluid will disperse any water in the old fluid into the new fluid evenly, giving you the new, higher boiling point throughout your brake system. Hell, unless you're flushing your brake system a couple of times you're still going to have old fluid in the nooks and crannies anyhow- but this method won't be a real big help if you're already suffering from boiling brake fluid. And, oh, yeah- don't hit your brake lever/pedal until you put fluid in the reservoir first, or you will hafta bleed'em. Water is introduced from the reservoir-end of the system AFAIK- and is from atmospheric humidity... ….unless you've laid it down in a creek, of course. The diaphragm in either reservoir is acting like a bladder to reduce surface area exposure of the brake fluid to the atmosphere, while still allow level changes from brake wear or over heating.

some notes:
Do not touch your brake lever or pedal between steps 1 & 2. Use a syringe or a turkey baster or baby-snot-sucker thingy to extract the fluid. The most time is spent taking the reservoir cover off . Do this once a year and every time you put new brake pads in and you should never have any problems. Also this will not solve a spongy brake problem caused by air already in the system, but it will keep air out during the fluid change. Don't open any bleeders or banjos unless it's necessary. Clean the reservoir cap off beforehand, and keep everything clean-clean-clean.