Brake fluid?

[beemer]

Iv'e noticed that due to the very hot weather we are getting over here in the UK,for a change!!!my front brake fluid has expanded?the brake lever has less of a space before the brake comes on,and although the front wheel hasn't locked up,i can feel it binding,do i need to replace the brake fluid?or is it something else,the fluid is up to the MAX level mark on the container,in colder weather it's fine,i don't have any braided hoses,thanks,Julian.

[montmil]

When was the last time you changed brake fluid? First suggestion would be to flush and replenish the brake fluid in the system.

Brake fluid is hygroscopic... it absorbs water which can cause all sorts of bad things within the brake system.

It's over 100F degrees in North Texas and I was riding! No expansion issues with my brake fluid but then it is fresh.

Monte

[Bob_Roller]

I second the recommendation of replacing your brake fluid .

I ride in 105-120 F. temperatures for 6 months out of the year, and have never had a problem with the brake system, but the relative humidity here in the northern Sonoran desert, averages less than 20% all year round .

You need to replace the brake fluid at least once a year .

[beemer]

I replaced it a couple of months ago,but the can i had has been in the garage for some time,so i guess it's bad,i'm getting some new today,thanks.

[Justin B.]

There also is a relief port in the master cylinder that often becomes clogged.  When you have all of the brake fluid sucked out look down in the hole in the bottom of the reservoir.  There will be a bigger hole and another pin-sized hole, this smaller one often gets clogged...

[montmil]

I replaced it a couple of months ago,but the can i had has been in the garage for some time,so i guess it's bad,i'm getting some new today,thanks.

UhOh.

Unless the stored can wasn't almost full and tightly sealed, you may have tripped across your braking problem.

Buy a fresh can of brake fluid, check that tiny hole, and you'll probably be good to go. BTW, does it rain very much where you are?  

[MrRiden]

What Justin says about the return port in the master cylinder is a prime suspect. Sounds like the application of the brakes with no return for the pressure has given you a stiffer lever and the calipers my not fully release the pads from the disc. You may find it difficult to bleed the brakes on replacing the fluid in that the lever will not firm back up. If this happens I'd be pretty sure the return port has become clogged.
rich

[beemer]

Can i clean the port with a very fine needle?

[nhmaf]

I use a small bit of copper wire and go carefully - the alloy body metal is fairly soft, so be careful not to make a gouge

[beemer]

I use a small bit of copper wire and go carefully - the alloy body metal is fairly soft, so be careful not to make a gouge

Ok,thanks.

[beemer]

I replaced it a couple of months ago,but the can i had has been in the garage for some time,so i guess it's bad,i'm getting some new today,thanks.

UhOh.

Unless the stored can wasn't almost full and tightly sealed, you may have tripped across your braking problem.

Buy a fresh can of brake fluid, check that tiny hole, and you'll probably be good to go. BTW, does it rain very much where you are?  

Yes it rains like hell most of the time!!!!
Changed the brake fluid this morning and went out for a ride before the rain starts!!!bike seems fine now,i also cleaned the small pressure hole,
looks like i will be inside this afternoon with a can of beer watching the women's wimbledon final!!