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I found a method for burping (get the air out of the circuit) hydraulic disc brakes in YouTube (see here). The method is:

1) Rotate/move the hand lever assembly until the reservoir cap is facing up and at level.

2) Take off the reservoir cap.

3) Slowly squeeze the lever repeatedly, until no more air bubbles come off.

4) Refill the reservoir with brake fluid.

5) Put the cap back on and return the lever assembly to his normal position.

To me it looks far more simpler than the standard procedure, and can be used in an emergency on the road (Obviously, it doesn't apply for replacing old fluid).

What problems can you see with this method?

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  • Not all bubbles will rise to the top but it certainly works for those that do.
    – paparazzo
    Dec 5 '14 at 17:46
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  • You aren't assured of getting all the air out of the system. If your bubbles are further down and this doesn't remove them, you may actually introduce more air than you remove when you replace the cap.
  • You won't effect a fluid change this way.
  • You won't replace the crush bolts and other pieces swapped at the true bleed that are potential sources of failure.
  • If something happens and you bump/spill some fluid, you are SOL for replacing it.
  • If you have a leak that has introduced air, this may not help any.

Not to say this isn't a decent method to try for a home mechanic as an initial troubleshooting step if you are into it. It may be done faster, with little to no cost, and may help some issues. However, you are correct, it does have several shortcomings.

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  • One more problem with this so-called "burping" is that it overfills the system, which can cause damage to the reservoir bladder, and i will become a bit pain when the brake pads need to be renewed. Jan 18 '17 at 4:30
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I have some entrance level Shimano hydraulic brakes (bl-m445; br-m445) and while trying to bleed them, I accidentally overtightened the bleed nipple thus resulting in the threads being busted. I put some teflon tape on it and reinstalled it in the caliper, then resorted to burping the system. Although it took a while (max 15 mins) I managed to get from something where the lever could easily touch the handlebar to a firm, airless system that feels like a brand new, quality bled brake.

I'd say that by removing the brakes from the bike, putting in a bleed spacer and attaching the lever to something so that the reservoir oil is leveled (with the caliper hanging down), using a bit of tapping on the line, caliper and lever can give just as good a result as a bleed.

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I fixed my brake using burping, and didn't even add additional oil.

I accidentally got a lot of air into the caliper and my brake didn't work at all. Without opening anything, I leveled the system so that air bubbles will travel only upwards towards the handle, and started pumping the handle. Press the handle gently so bubbles won't move down, then release it quickly so they'll be pushed up. Keep doing it a few minutes. The reservoir at the handle is designed to have some air trapped inside, it's OK for the bubbles to collect there. Of course it's better to add some oil if you have any.

I had to disconnect the caliper from the frame to keep it below the pipe, so after some pumping my pistons were extended all the way. I used a screwdriver to push them back, they are held in extended position by friction.

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This is a quick fix, having brakes is safer than not having brakes, but I would not use this as an alternative to properly bleeding brakes, you're not guaranteed to get all the air out.

This kid has much bigger problems than air in his brakes, did you notice his hose fitting? His "burping" hack isn't going to last long because he's sucking air straight into the master cylinder by riding with a broken hose. It's seriously just dangling off the caliper with the sheath almost completely cut, one hard stop and that line is going to blow right off the fitting.

Dot oil is dirt cheap, you use very little to bleed Juicy brakes, and you can get a cheap bleed kit from your local pharmacy for $2 (ask for a disposable oral syringe with a luer lock tip). I know of one pharmacy that even stocks extra syringes because it's across the street from a couple bike shops. Bleeding your brakes is way faster and more effective than burping your brakes.

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  • Yes, I notice that. Shimano mineral oil is not cheap: the 50ml bottle cost $15. For that money I get a Ballantine Finest (750ml), that "refills" me many more times. Oh, the funnel cost another $10. One time expense, but not easy to find in this country.
    – user5369
    Dec 5 '14 at 23:42
  • Hopefully oral luer lock oral syringes no longer exist. Luer Lock is the threaded system meant for IV/IM/etc administration. Luer Lock syringes should be sterile and come in sterile packaging. Oral syringes have moved to a slip on version with sizing differences so that a needle cannot be attacked since they are a non sterile product. This change happened many years ago after various mishaps across the world with oral solutions being administered via IV routes. Dec 9 '14 at 0:05

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