Brake problem

[chef_boy]

In the last few months I've been noticing my front brakes have been getting weaker (wait for me to explain!)
I have goodridge lines with EBC pads and stock everything else. What's been happening is the amount of effort to pull the lever is less also it can be pulled all the way back to the bar. When this first started to happen I bled the brakes and It worked for another month (ish). I even tried using a different brand of brake fluid, which turned out to be worse so I went back to Castrol. But today I noticed it happening again.

A little bit about my bike. Its a 2008 GSXR 600 with 48700kms and I ride it pretty much every day.

I dont know a great deal about the inner-workings of the brakes, but I'm thinking that something in there needs a little love, just cause of the KM's.

Idea's?????

[Lane]

Are you losing any fluid anywhere? If not, I suspect you master cylinder needs attention.

[chef_boy]

No fluid anywhere that I can see.

[ronski]

Get yerself a master cylinder rebuild kit, use genuine parts if you can. It should have a new piston and seals. Rebuilding is fairly easy, youll probably need circlip pliers. Rebuild the calipers with new seals while youre at it

[jlyall]

Pulling apart the callipers in the CBR250 will I need circlip pliers as well?

*End of hijack

[vitamine27]

burp the top bolt periodically, ie when it starts getting soft,

brake lines are designed to give controlled flex, braided lines are only good for 70's shit,

pulling apart calipers in CBR 250 just requires pumping the pistons out, and using small smooth flat blade screwdriver to pry seal out, then you need a homemade tool to scrape the seal groove clean as corrosion builds up, pressing on seal

[jlyall]

^Ok that's exactly what I thought. Thanks V27.

[lico]

YEah if it gets better when you bleed it, then slowly gets worse again, it's obvious that you're losing hydraulic pressure in your lines somewhere. This is almost certainly because a cylinder piston seal is weeping. This will be more obvious if you have braided lines because they do not expand and therefore the weakest link in the system is the seal where fluid will weep out. Only a tiny fraction of fluid needs to be lost (few mils) for you to lose enough pressure that your brakes become shit.

TLR Answer: Rebuild your master cylider and calipers by replacing the seals/o-rings on the pistons so that hydraulic pressure is not lost through them.