So I did a bubble bleed on my rear brake. I know it’s supposed to be a stopgap and you’ll need to do a full bleed soon, but can someone explain to me why it won’t stay “fixed” once it’s done?

Is it because you can’t release all the air in the system without doing a full bleed?

because there are inconsistency problems with a lot of Shimano brakes e.g. in my garage i have 2 SLX, 2 XT and 2 Zee brakes. Both SLX and one Zee suffer from a wondering lever, the other Zee and the XTs are spot on.

WTF is a bubble bleed?
There’s nothing easier to bleed than Shimano brakes. I can’t imagine there’s a faster way to do it than the proper way which is literally 5 minutes including removing and replacing the rear wheel!

PeterPoddy – Member

WTF is a bubble bleed?

http://www.pinkbike.com/news/tech-spotlight-5-minute-bubble-bleed-2014.html

That’s obviously a technique designed for Avids that are a pain in the ass to bleed and have seal tolerences you could drive a Volvo through!
Pointless with Shimano. I could do a full bleed possibly slightly faster than that.

Maybe, but it does work!

Maybe, but it does work!

Try telling the OP that! Doesn’t seem to be working for him

Maybe, but it does work!

Try telling the OP that! Doesn’t seem to be working for him[/quote]

… … ?

?

Apparently my keyboard on my phone has started only excepting punctuation in forum replies… Odd.

Anyway… as you were.

@nickjb I am the OP!

It works, but the “bleed” seems to last about one ride’s worth before it starts to pull back to the bar.

Then I think you’re looking at the well documented Shimano hydro brake master cylinder death.
There’s LOADS of threads on here about it.
Shame as I’d like to upgrade my M770s to some newer ones, but concerned I’ll have issues with the new ones.

Then I think you’re looking at the well documented Shimano hydro brake master cylinder death

Based on what evidence? A dodgly “bleeding” technique aimed at another brand (that incidentally has the worst reliability record in the business) come on, have a word with yourself.
Bleed it properly, from the calliper upwards.

My XT rear brake was acting like that, drove me nuts!

Solved it by giving it a damn good full bleed with the bike upright so that the hose was vertical using the EpicBleed kit. Emptied the system completely then slowly pushed a syringe full through from the caliper while tapping the caliper, hose and lever to eke out any stubborn bubbles. Did the loosen-squeeze-tighten-release method for all the fluid in the top syringe back down with more tapping. A surprising amount of small bubbles came out!! Has been fine now for over 6 months since doing all that.

It works, but the “bleed” seems to last about one ride’s worth before it starts to pull back to the bar.

Or in other words it doesn’t work. A bit like fixing a puncture by pumping your tyre up.:P Just bleed them. Its quick and easy with shimano.

@nickjb I am the OP!

https://youtu.be/xECUrlnXCqk

Alright, I’ll have a go and report back.