bluebeast06

+1 on the water in the brake fluid. it will feel fine while cold and stopped but after a little use they will feel spongy. I would say change out the fluid for new and bleed the brakes i hope that helps you out.

oldninjadude

After this happens the first time, Would the bubbles not remain & cause it to feel spongy always then?

trackdayhero

No, the bubbles go back to liquid when cooled. When the temp hits 212 the water changes state from liquid to gas. When the temp gets back down below 212 it changes back to liquid. I have plenty of experience with this on dirt but have never experienced it on the street. It sucks when you are in the middle of a woods race and half way through the race you lose brakes. Get back to the trailer and they work fine. Flush the system with new fluid and all is well. I'm not saying this is this guy's problem but if the fluid hasn't been flushed completely with new fluid it is something I would do before ordering a master. It's wise to flush your braking system with new fluid every year or two, especially if it is subject to extreme temperature changes. On the same token, just air bubbles in the system will have a more pronounced effect when the brakes are hot because the air expands as it heats up.

Iceman

Brakegood fluid is considered a "dry" fluid so if the cap has been off extended periods of time then it could have absorbed the moisture from the air causing spongy brakes

ninjazx6r636

I had a similar issue. I think mine was the lack of use from bike sitting. More and more I rode, they worked normal again.

trackdayhero

Here is an interesting read on the subject of moisture in the brake fluid:

Why Change Brake Fluid

ninjazx6r636

very interesting indeed!

oldninjadude

Right, makes since too.
I change mine every two years.

dj23bol

I'm having a simalar problem with my front brake there is just no brakes at all the guy who sold it to me said he tied the lever to the bar over night and it went nice and hard but after a ride went to no brakes again is this air in system? Or fluid or master cylinder.

propaintball

I usually just gravity bleed? Always works fine for me?

TheEvilTwin

Most of the bikes I see need the fluid changed. Some, have old stock lines that need to be replaced. A few have master cylinders that are shot. If your lever goes straight to the grips with very little (or no) braking force you probably need a MC. If it is just very spongy lever feel then fluid. If your bike is +6 years old and has been stores outside then you should seriously consider lines too.

dj23bol

yeah cheers eviltwin i think its master cylinder then. its got steel braided lines on front and back but yeah it goes straight to grip.