when do you need to bleed hydraulic brakes?

Giraffoto

This is a slightly techie question, but I’m posting it here because it’s more for my curiosity than to solve anything I’m planning to do. So, when do people really need to bleed hydraulic brakes? On a car it gets done when the brake fluid gets replaced, is it needed more often than that on a bike? I’m curious about this because the number of threads on the subject suggests that there are people out there doing it every week for a bit of fun

1mancity2

once in 2 years on my brakes.

ricardo_smooth

if/when they feel like cack and under perform despite changine pads and cleaning etc

nicklouse

When the fluid has been contaminated or boiled. So that means rarely.

Anonymous

Indeed. Far less than people assume and don't blindly follow advice of "oh you need to bleed them mate".

VWsurfbum

hydroscopic fluid goes off at approx 2 years, so i would suggest then but even so thats only because its absorbed a lot of moisture and would boil easier, depends how hot you get your brakes?

Redhog14

What are hydraulic brakes?

The Rookie

VWsurfbum wrote:

hydroscopic fluid goes off at approx 2 years, so i would suggest then but even so thats only because its absorbed a lot of moisture and would boil easier, depends how hot you get your brakes?

As most (all?) bike brakes are sealed systems, the fluid being hydroscopic is irrelevant as no moisture should be getting in in the first place.....unlike car/motorbike system that runs a ventilated master cylinder.

Simon

VWsurfbum

The Beginner wrote:

VWsurfbum wrote:

hydroscopic fluid goes off at approx 2 years, so i would suggest then but even so thats only because its absorbed a lot of moisture and would boil easier, depends how hot you get your brakes?

As most (all?) bike brakes are sealed systems, the fluid being hydroscopic is irrelevant as no moisture should be getting in in the first place.....unlike car/motorbike system that runs a ventilated master cylinder.

Simon

True to a point.
it still goes off with age. just like a tin of baked beans

The Rookie

No, it ages due to water/contaminants and oxidation, a sealed system will exhaust those in the first month or so, after that, no effect.

So not true to a point, just true!

Tins of baked beans from the 70's have been opened and found to have the contents in perfect condition......although I havn't tried the tin of Salmon I found that is priced in Shillings and pence......it hasn't 'blown' the tin though!

Simon

VWsurfbum

Sorry but i disagree.

Tinned fish is bad at the best of times, maybe take it to antiques roadshow

Anonymous

Tinned anchovies are best at any time, off or not. Though so much salt not sure they can go off. Anyway, great on Pizza

The Rookie

As someone allergic to any seafood, I have to disagree!

Simon