Gravity bleeding disc brakes, does it work?

[Swiss Roll]

like this (action starts at 5.20):

Seems a bit more foolproof than the conventional method.

 

[cozzy]

Yep. Done it for years. Check out the syndicate video where marshy does it on Greg's saints.

 

[Gary]

Except air rises. So a ONE MINUTE gravity bleed is not guaranteed to remove all air from a hydraulic brake system.

She's a youtuber. Like most youtubers she's just copying and rehashing someone else's content.
In this case ex Minnaar/Syndicate mechanic Jason Marsh's
Only she misses a couple of steps Jason does.
Blindly.
Because she's a youtuber and Jason is a mechanic.

also a bleed is not 100% fool proof as wandering brake point issues in a brake (especially Shimano) don't always come just from the bleed.

 

[Gary]

Now edited I mistakenly spelled the words "fool proof" as "full proof"
The meaning of fullproof is actually - impervious to filling
So in the case of Shimano's wandering lever bite point issue both meanings actually work quite well.
.
Infact it's actually a little foolish to expect a shimano brake's wandering bite point to be fixed by simply bleeding the system. Whether by gravity or standard syringe bleed.

 

[Swiss Roll]

Thanks for the replies, guys.
That video is quite helpful, thanks. As Gary said, Mr Marsh did quite a few things that she didn't do. I had the feeling that brake fluid going down might not automatically push all the air out of the bottom. Interesting tidbit about the brake oil boiling, that sounds not good.
A question though, if a one minute brake bleed isn't sufficient, what is? Pouring more oil into the top? Or letting it sit? Pump/tap everything, as per usual?
Typical oz overstatement though, calling the flimsy shimano cup a bucket.
To be fair to her, her schtick is learning how to fix bikes, and they do say in the video that they learned this technique from a race mechanic.
Shirley impervious to filling would be "fill proof"?

 

[Gary]

A question though, if a one minute brake bleed isn't sufficient, what is?

With a Shimano brake?
Worst case, often a complete replacement caliper as Shimano caliper pistons frequently have sealing issues.
But if that's not the case you need to rid the caliper of every last air bubble. And it's the caliper design and placement of the bleed nipple which causes this to be difficult. Plenty folk havd reported an improvement from using non-shimano mineral oil. (but that voids your warranty)

Shirley impervious to filling would be "fill proof"?

Tomato tomato

But yeah.

It simply occurrred to me my wrong spelling wasn't actually all that wrong. [/nerd]

 

[Kingerz]

Yes it works perfectly, is much easier, done in the automotive industry anyway and I have done it this way always. Sid's video is spot on.

 

[04fuxake]

Typical oz overstatement though, calling the flimsy shimano cup a bucket.

Jason Marsh is from NZ.

 

[Bndit]

Yep. Done it for years. Check out the syndicate video where marshy does it on Greg's saints.

This is how I bleed all my brakes, great video and works!