Has anyone else noticed some peoples strange obsession with continually bleeding brakes?

I've never bled a mountain bike brake due to poor performance, only when changing hoses, etc. Why do people do it? What are they hoping to achieve? Are their brakes / some modern brakes actually that bad? If they really have got air in them after a fortnight since they were last bled, there's obviously a problem that goes beyond what bleeding will fix

I've noticed that, and I've only ever bled due to poor performance and changing hoses. However with Shimano I've not had to bleed when shortening hoses which has been great.

My lad started complainig about needing his front brake bleeding.
I had a look and addressed this after another couple of rides.
There was no fluid in it.

I bled mine the other day as I noticed a lot less lever throw on a particularly cold (sub zero) ride, which suggested that there was moisture in the fluid which was freezing and expanding. Anyhow, fluid was proper black when it came out. Fine now, but even with fresh fluid, I've decided not to run hydraulic brakes in Finland and will be fitting my BB7's.

Some brakes are known for allowing air in slowly leading to spongyness and finally no breaking performance. I have two acid juicy 5 that do that. Shimano seen bomb proof even at the cheap end.

There might be a correlation between folk who are bleeding brakes weekly and those permanently slamming on the stopping. My bouncy bikes need much more attention than those built and used for trails and tarmac.

Brake bleeding = removing air.

Brake fluid flush = complete change of fluid and includes removing air.

AFAIK the black and crap in the fluid is because of general degradation of the brake seals etc. Also over time the fluid collects moisture, to what extent depends on your brake fluid and how well the system is actually sealed. With car systems, you get your dot 3, 4 etc. the higher the DOT number, the higher the boiling point so the higher DOT fluids generally used for more motorsport oriented applications, but conversely the higher DOT number fluids also absorb moisture at a higher rate and therefore requires flushing through more often. This information must relate in some way to what we're talking about...!

Personally on the bike I only ever bother bleeding/fluid changing if I feel it needs it, normally quite rare tbh, not even when changing hoses. But yes it can be required periodically.

I make sure I bleed the brakes on my car once a year though, but that's only the make sure I get fresh fluid round the pistons coz they do have a bit of a history/reputation on my car for getting sticky and needing rebuilds - I'm hoping a bit of periodic bleeding helps reduce that necessity

s8tannorm wrote:Has anyone else noticed some peoples strange obsession with continually bleeding brakes?

Not noticed that though I must admit.

st8tannorm wrote: If they really have got air in them after a fortnight since they were last bled, there's obviously a problem that goes beyond what bleeding will fix

One of those reasons might be ineffective bleeding...I found avids a bit of a pain to bleed, so I had to repeat the process in less than a week, but more coz I didn't do it right first time and it took a week for the effects to re-appear and to notice...

I had giant mph which were rubbish. Needed bleeding every few weeks, even with light use. Replaced the seals often as well. They gunged up as well and didnt release very well at times.
Now have shimano's, which need no fettling.

Run cable brakes on the fat binge, just replaced the cables after 10 months

Hydraulic brakes on the singlespeed are still going well after 18 months use. Could do with a slight bleed if I wanted perfection but doesn't bother me

I had giant mph which were rubbish

Were they the odd semi-open ones that you had to adjust on the fly as they heated it?

OO Fatty's used to come with hateful spiteful awful Avid Elixir 1's. They needed bleeding after every 3-4 hours of riding. I lived with it for a few months and then junked then for some el cheapo Deores from Merlin Cycles. Didnt need to cut them down and the factory bleed has been fine for nearly two years now.

Ive got some Formula RX brakes on my Meta that are giving me trouble though. They bleed the same as Avids so Im well practiced at it (see above) but the issue seems to be that the pistons retract a bit too far, so the first pull of the lever comes back a bit too far and they then firm up. Anyone got any suggestions on this? Ive tried pulling out the wheel and advancing the pistons, but it has made no difference. Bloody annoying as they're much nice brakes to use than Shimanos. Not as powerful I think but way more modulation.

s8tannorm wrote:

I had giant mph which were rubbish

Were they the odd semi-open ones that you had to adjust on the fly as they heated it?

Yeah. I actually liked that feature. Everything else about them was cack.