Brake Problem

Hi,

I have done quite a few trackdays now and seem have the same problem nearly every time, after about three sessions my brakes start to fade and become very soft and spongy, sometimes they get so soft I can pull the lever all the way back to the handle bar and even then they dont have the stopping power they should have . I'm guessing this has something to do with the break/brake fluid heating up, because the after a few hours break they seem to return to how they were at the beginning of the day?
Has anyone else experience this, or know exactly what is happening or how to solve the problem?
Would using DOT 5 Brake fluid possibly help?

Thanks
Will

[Sid Squid]

Replace the fluid, sounds as if it's degraded. I don't like Dot 5 in road vehicles, it may not damage paint but it's disadvantages outweigh that.
5.1 would be a better choice, but I've never had any troubles - even when used hard - with 3 or 4. If the fluid is in good nick, you'd have to use it bloody hard to outdo the performance of 3, I rather doubt any of us road riders would push 4 hard enough to have trouble with it, even at the track.

[northwind]

What sort of pads/discs? Could make a difference, that...

The thing is, that I've experienced thew same problem on three different bikes, an SV, CBR600RR, and a ZX6R so it is unlikely that the break fluid has degraded in each case? and they would all have had different disks and break pads?
Is it possible that the method i uses for breaking on trackdays, i.e. late and hard causes the brakes to have this effect?

[northwind]

Possible... Or, do you do your own servicing?

[Spanner Man]

Morning all.

For once I have to agree with the Squid regarding dot 5 in road vehicles. I've found that a dot 5.1 or a super dot 4 usually sorts out track day fade, providing the braking system is in good order....Braided hoses & good quality pads like EBC HH can help too.
As brake fluid doesn't circulate in the system, the fluid in the caliper gets well and truly heat treated. Some folks I know take a bottle of fluid with them, and after every couple of sessions release the bleed nipples and squirt a couple of shots of fluid into a clean rag, thereby allowing fresher fluid into the calipers.Then they top up the reservoir.
Do one caliper at a time and DO NOT try this unless you have a good understanding of the principles of brake bleeding.

Cheers.

cheers for the help guys,

as for servicing the, the SV was always done by dealer i bought it from, i did the CBR myself, and i've only had the ZX a couple of weeks now but i think it has been fairly recently serviced by the dealer.

I've done a search but coulnd find anything of help so could anyone possibly explain what the difference between the fluids are eg, 4, 5, 5.1 and how they work?

Thanks