I bought these to build up a bike cheaply. Can’t comment on how they work yet, they certainjly look neat but I am curious about how to bleed them. I am used to bleeding Hopes and some old Shimano Saints, which all have bleed nipples built in.

I had to shorten the hose, so I did this with the spare hose end bits that came with the brake. This resulted in a need to bleed them as I let a fair bit of fluid out.

The bleed port in the caliper is closed with just a bevel-ended screw. There is a fine rubber grommet that seals around the head of it, but there is no apparent bleeding capacity built in. As I had a spare old Hope caliper around, I used the bleed nipple off that to bleed the brakes (it is an M6 thread also). Undo nipple, squeeze lever, close nipple, release lever, repeat until no bubbles emerge whilst keeping the reservoir topped up in the traditional way. That seems to have worked OK, and I have left it on (so that is one brake sorted).

So here’s my Q. How is it supposed to work? I have seen those bleed kits advertised which have brass screw-in bleed nipples which, presumably, you have to remove and replace with the plug once you have done the bleeding. If I was doing it that way, how would I stop at least a sparrow’s fart of air getting in to the system via the caliper when I undid the bleed nipple? Am I missing something here?

Trying to remember how I do these at work…vaguely remember using bits of an avid kit and reverse bleeding it.
When you take the nipple out you’ll lose a bit of fluid but I’ve not had any trouble with air getting in.

You need a bleed kit like the universal one from Epic LINK Then screw in at both ends and push fluid up from the bottom. Lock off the lever syringe and disconnect the caliper one then replace the screw. Then disconnect the lever syringe and replace the screw. Basically it’s the same as the Avid system, but much easier to do. 😀

They really are great brakes, especially for the money.

Thanks @lazy and @boris – I will get a bleed kit and give it a go. Though, one could buy a couple of bleed nipples for that price. I am still wondering how no air gets trapped in when you replace the plug, but obviously it doesn’t otherwise you would have noticed.

I just looked up a bleeding Avid brakes video – blimey I see what you mean @boris, put me off buying a set of them.

I’ve just taken delivery of a set of M2s and the rear hose looks like it is a bit on the long side, I’ve already got a shimano bleed kit and mineral oil but what are the actual port thread sizes? (I can’t be arsed opening it up now) and will my old shimano bleed nipples fit?

I don’t know the bleed nipple sizes…I just remember faffing around with an avid kit and bits of whatever other kits were left in the box 🙂 I don’t remember them being particularly difficult to get a decent lever though.

I’ll nick a shimano bleed nipple off an old caliper just to see if they fit and/or the lever port nipple from the shimano kit.

I did manage to find this but it’s not quite clear if it fits the caliper, lever or both….

@cookeaa – the one in the caliper is 6mm the one on top of the lever is 5mm, both standard metric thread I think.

Cheers, I will have a poke in the spares box tonight, I reckon I might have the bits to do it already.

you can shorten the hose without needing a bleed, same procedure as shimano recommend…
squeeze lever to bring pads together slightly
cut hose at lever end
reterminate with new olive / insert
push pads back out to force any air at lever end up into lever

bobs your uncle.