Do I really need to change my fluid.

Originally Posted by sdusk

Got network cables on the brain today...

Originally Posted by rictus01

Indeed you should change it, brake fluid is hydroscopic...

Sorry to be a pedant but it's hygroscopic.

Can you change to dot 5.1 without flushing the system then? Cos if so, as far as I can gather there's no reason not to change to it, bar what - £3 or £4 extra cost?
Brake fade seems a pretty common problem amongst most bikes on track, so must be worth trying something with a higher boiling point?

whats the easiest way to bleed them then? Im gonna get a 2 line setup but want it to be hassle free

[northwind]

Big syringe, squirt in from the bottom... Definatley my favourite method. I'm not vey good at bleeding brakes But this makes it a quick and easy job. Didn't even need to bench bleed Matttheloony's m/cwhen we did it, literally squeezed fluid in from the calipers till the reservoir started to fill, then squeezed it back down with the lever. Repeat to (don't) fade

Hi All.

One important point has not been raised here, unless I missed it. As time goes on and the fluid has absorbed moisture, the boiling point of the fluid is reduced so you may notice brake fade start to creep in. Not good on a bike.

Tim.

On the subject of brake lines, I know you're supposed to use new brake fluid out of a new bottle for bleeding brakes each time. However, I was wondering for how long after it has been open is acceptable to use it?

Basically I've bled my brakes 2 days ago, couldn't get them right. Left it overnight in case they were airated. I've now come back and am ready to give it another go. I take it the new (opened 2 days ago) fluid, which has been kept in the bottle with the lid on since, will still be fine? How long could you leave it, a week? More?

Just curious...

[BillyC]

I'm guessing here...

If you leave the fluid too long, the water in the air will condense and be absorbed by the fluid itself. This could happen from the first time you open the bottle, so best to use as much as you can, and always replace the lid after use.

Maybe it's capable of absorbing water straight out of the air at its surface - no condensation required.

I guess it could depend on how much is left in the bottle... a little trickle, I'd buy a new bottle. Enough for a top-up, then possibly okay.


NB: this is not official advice - just my thoughts.

[jambo]

Originally Posted by BillyC

If you leave the fluid too long, the water in the air will condense and be absorbed by the fluid itself. This could happen from the first time you open the bottle, so best to use as much as you can, and always replace the lid after use.

Correct, however I've found in the real world as long as the top is put back on securely to make an air tight seal the fluid will be fine for quite a while. If you pour it out and it looks dark forget it, but as long as it's sealed up tight it'll be fine for a while. I've used brake fluid that's been opened a month or more before hand provided it looks ok. It's about ammount of contact with moisture in the air rather than time since manufacture / opening 1st AFAIK.