Just got a new XT brake back under warranty, shortened the hose doing the whole pushed out pistons bit, it all went well.

Flipped the bike upsidedown(*several hardened STW’ers faint in disgust) to remove the wheels to get it into the car, later flipped it back up the way you are supposed to have it when riding it, and had zero resistance in the rear brake at all….not a jot.
It gradually returned after a bit of squeezage.

This was following a day and a half of the bike hung up with the levers zip-tied in to the bar following the hose-shortening.

What have I done wrong? Do I need to bleed it? Will I die?
Thanks 🙂

Yes bleed it there will be air in the system, normally in the reservoir, this will now be all over the place!!

Quick bleed and off you go.

(nothing wrong with turning bike over too)

there’s air in the system. all the zip tie thing does is force it into the reservoir, not remove it.

As you’vce found it just goes back down the hoses when the bike’s inverted.

best bet is to rebleed but you won’t die (probably) as long as you have pressure at the lever when you start the ride.

Damn!- about the bleeding.
Oh good – about the not going to die.. 🙂

I would bleed it.

When you turn it upside down there is the potential for any air in the system to move from the lever to the caliper, hence the sponginess.

Edit: too late.

And there’ll still be plenty reccomending not bleeding after shortening hoses 🙁

I’ve had one like that for a year now, you just need to pump the lever before you set off. it doesn’t have any effect on the performance, at some point I’ll get it sorted out.

And there’ll still be plenty reccomending not bleeding after shortening hoses

I thought that pushing the pads out, then back in after would get around this.

I’ll bleed it I think, although I’ve not seem to have had much luck with bleeding shimano yet. Spot on with my Hopes…

numpty question…

so this means that you might need to bleed your brakes after you have taken your bike on a plane?(cos its going into luggage hold…upside down etc)

Only if they needed bleeding anyway, presumably. It’s a closed system, n’est-ce pas?

so this means that you might need to bleed your brakes after you have taken your bike on a plane?(cos its going into luggage hold…upside down etc)

Only if they needed bleeding anyway, presumably. It’s a closed system, n’est-ce pas?

You’d think so, but my shimano’s did when I got to Spain, odly, my avid’s which have been an utter reliability disaster every other ride were competely fine after a flight! On that occasion the zip tie trick worked just fine. I’d take a bleed kit with me now just in case.

@thisisnotaspoon. thanks, will bear that in mind. 😛

so, if your brakes are working to a t. pre-flight and find that they require bleeding post-flight, surely that means a loss of brake fluid during the flight.

being a closed system, as ‘cougar’ mentions, then any air getting in must be due to a (small) leakage of brake fluid, all things being equal…?

just thought i’d ask cos it might mean storing brake pads seperately from bike etc, pre-flight.

has anyone found a puddle of brake fluid in their bike-case, post flight?

so, if your brakes are working to a t. pre-flight and find that they require bleeding post-flight, surely that means a loss of brake fluid during the flight

nope, the assumption is that the reservoir wasnt 100% full

Aye… Basically, you have a closed hydraulic system which pushes the brakes, with a reservoir of spare fluid on top. That reservoir should be completely full of fluid and have no air in it. As long as there’s no air, it doesn’t matter if you turn the bike upside down.

But if there’s a bubble in the reservoir (as there often is) then it’s not a problem in everyday use but when you flip the bike, it will rise- and so can get into the pressurised system.

So if you have a perfect bleed, it won’t happen but actually, a fairly-good bleed is usually fine and the first you know about it is when this happens.

And there’ll still be plenty reccomending not bleeding after shortening hoses

Yep. Because it’s very easily possible to shorten/swap hoses without bleeding. I did it with my Shimano M785s, which needed to be shortened adn have the levers swapped.

I used another trick, that I thought up as well as the one of moving the pistons out a touch.

Remove pads and move pistons out a bit.
Undo 8mm bolt to detach the hose from lever.
Cut hose to the required length put the olive on and hammer the barb in.
Use fluid from the cut bit of hose to make sure the fluid level is right up to the top of the freshly cut hose and put the excess into the open hose port in the lever.
Put hose back into lever and tighten up.
Open the bleed port on the lever and push the pistons back. This pushes the excess fluid out and any air along with it.

The bit in bold is my little trick.

As said above, the air that was in the reservoir moved into the hose and caused the spongy lever. A bleed will sort it.