Anyone swapped a brake hose without needing to bleed?

Splasher

Need to fit a longer hose to a Hope Mono Mini Mk I. Anyone tried pre-filling the new hose with fluid or any other tricks to avoid the need to bleed?

Ta

nicklouse

you will need to bleed it.

Anonymous

Not necessarily, not fully sure about Hope Mono Mini Mk I's but the deore and deore lx hyrdraulics sometimes don't need bleeding. Make sure you turn the lever so no fluid can fall out and that the cable stays pointing upwards when removed. If you can bleed it ,do though, as dot 3 and 4 both absorb water and are made usless if they're in contact with the water in air for too long.
Hope that helps!

nicklouse

mcflask07 wrote:

Not necessarily, not fully sure about Hope Mono Mini Mk I's but the deore and deore lx hyrdraulics sometimes don't need bleeding. Make sure you turn the lever so no fluid can fall out and that the cable stays pointing upwards when removed. If you can bleed it ,do though, as dot 3 and 4 both absorb water and are made usless if they're in contact with the water in air for too long.
Hope that helps!

so how do you put the fluid in a new hose?

he is not shortening a hose he wants to fit a new longer hose and what is the easist way to get fluid into the hose? fit it and bleed it.

Splasher

How about this for a scheme:

Take old hose off and swap fittings to new hose.
Fit to caliper but not lever, and fill hose by forcing fluid into caliper bleed nipple using syringe and hose.
Fit hose to lever assy.

Might work?

Want to avoid the whole "fill resevoir, 2 pumps with lever, fill resevoir, 2 pumps with lever" never ending bleed cycle if I can.

Bugly

as Nick says you WILL NEED TO BLEED it You will not be able to get the air out of the new house without bleeding.

Bleeding brakes is not rocket science guys, simple mechanics. Its simpler then the procedure you propose Splasher and is certain to work. However if you do try your bleedless method please post the results.

Splasher

New hose is on order, should be able to try Wed or Thur - will post results.

I've shortened them in the past without needing to bleed so I reckon as long as I can get the hose full (by filling from the bottom until it overflows).

Bugly, what's the easier method to bleed Hope Minis?

dave_hill

It really is easy to do it using the "bottom up" bleed method with a big measuring syringe. I've been doing this for years on motorbikes and MTBs with no problems.

I honestly can't understand how it is possible to remove a hose without loosing fluid??? I'd be interested to know though!

Splasher

Dave, as an amateur motorbike and bicycle mechanic of 25 years experience I would have agreed with you that it seems unlikely that you can break a hydraulic line without getting some air into the system requiring bleed.

The only reason I'm going to try is that to bleed the hope system bottom-up requires a hope kit with alternative resevoir cap fitted with a nipple to take the overflow fluid. Without this, the only way I know is to bleed it down to the caliper nipple using the master cylinder lever, topping up as you go.

What makes me believe it is possible was my experience shortening the hose for a previous build when I cut the hose, reassembled and assumed I would need to bleed finding that in fact the lever was still rock solid.

As I say, it may not work but I've got nothing to lose.

dave_hill

Well, you learn something every day if you aren't careful! I'll certainly be interested to know how you get on.

Just as a matter of interest (not being totally familiar with Hope brakes) is it not possible to remove the reservoir cap. drain the system right down so that it's empty, then force new fluid in from the bottom?

That way (in theory) you shouldn't need the special reservoir cap as there would not be any fluid in the system to displace.

Splasher

dave_hill wrote:

Just as a matter of interest (not being totally familiar with Hope brakes) is it not possible to remove the reservoir cap. drain the system right down so that it's empty, then force new fluid in from the bottom?.

Possibly an equally cunning plan! If plan A doesn't work, I'll give it a try and let you know.