Dammit’s adventures in mountain biking

Is it mineral oil or DOT fluid?

Mineral oil

I'm 50% convinced that something is leaking on the new lever, it kept producing bubbles far past the point that I thought it could actually contain that much air.

At least the boiling point is lower than DOT in that case.

I've done it before by putting them in the oven, but in hindsight that's probably not the smartest idea if you intend to eat food from the same oven

It's not out of the realms of possibility for @Dammit to get an oven specially for baking contaminated brake pads.

Watch this space.

Presumably a Miele one with some sort of app functionality to fine tune cooking time?

Fire is certainly one solution to this ongoing situation

Some say the brakes will end in fire,
Some say in ice.
From what I’ve tasted of this thread
I hold with those who favor fire.
But if they had to perish twice,
I think I know enough of Magura
To say that for destruction ice
Is also great
And would suffice

I'm 50% convinced that something is leaking on the new lever, it kept producing bubbles

If this is happening when you are pulling on the top lever to 'suck' air out it's probably because the seal on the syringe isn't good enough and it's just sucking air in from the outside, rather than from the inside out. Or something.

Nope- pushing lightly on the calliper syringe and then flick the brake lever and a cloud of bubbles is released- very tiny bubbles mainly, but every now and then a large one.

For around an hour before I started seriously losing the light and closed everything up

I think you need to ask Bezos if you can go in to the cold dark vacuum of space with Shatner - seem like the ideal conditions to get the air out of these bloody brakes.

Push Shatner out the door whilst you are up there

I'm wondering whether doing the hose clamping nut up to the specified torque (4Nm) is insufficient and I should give it a little bit more tight.

There are absolutely no bubbles being drawn into the calliper syringe as you pull a vacuum on it with the plunger, so I'm happy with that end.

It's the lever that is either a) storing a lot of bubbles inside it or b) there's some small gap admitting air, but only as you flick the brake lever.

Which might suggest that operating the lever is pumping air out of the master cylinder into the reservoir I suppose?

I believe I've once read about lab shakers being used to dislodge bubbles, it'd be a great addition to your tool kit.

I'm not sure how that would work with internal routing. Something that clips onto a hydraulic line that then vibrates, yes, but I can't remove the brake without cutting the hose, and it can't be re-installed without being split.

I'm wondering whether doing the hose clamping nut up to the specified torque (4Nm) is insufficient and I should give it a little bit more tight.

4Nm is practically nothing, 6-8Nm would be absolutely fine.
I admit I don’t bother using a torque wrench when tightening the hose nut on my brakes.

Bear in mind that the brake lever body is "carbotecture", which I think is a carbon-fibre strand reinforced resin.

I genuinely saw a mechanic with a vibrator in his toolbox for this exact purpose.

I was thinking there'd be enough hose between frame and lever to at least do the lever, vibrators are more readily available and easier to maneuver though.

Lfgss came for the cycling, stayed for the sex toy advice

The challenge there is that the lever needs to be held in a specific alignment to give the bubbles a path to the (for e.g.) syringe in the bleed port.

I suppose you could make a stand from an old handlebar that would sit on the jiggler.

Fuck me this really is like a soap opera when a character keeps returning to an abusive partner “but it’s going to be different this time”.

Plane Jane Shimano may not be as sexy or rare as Magura but you are likely to have a functioning bike more of the time.

For around an hour before I started seriously losing the light and closed everything up

Have you tried leaving the system open overnight before bleeding again the next morning? I just leave the syringes on overnight and then do a very quick bleed the next day, normally with zero bubbles. That is with Sram bleeding edge kit that screws in though, not sure what the magura set up is like.

I did - but that was with the brake lever that had a leaking master cylinder.

I closed everything up before test riding the bike yesterday - it's a shame that you can't check how your bleed has gone before putting the bike back to a normal operating condition.

6-8Nm wont crack the p̶l̶a̶s̶t̶i̶c̶ Carbo-dentures