'06 GSXR750 Front Brake Issue

I recently picked up an '06 GSXR750. I started going through the bike and am having issues with the front brakes. I bled the front brakes both at the calipers and at the master cylinder. It was difficult getting all the air out of the master cylinder, but I finally got a firm lever.

So here's my issue. The bike has sat for 17 days and now the front brake lever comes almost completely back to the bar. I started bleeding the front brakes again and the master cylinder has huge air bubbles. Again by bleeding both the master cylinder and calipers I was able to get a firm lever. So I guess what's my avenue to troubleshoot the problem? BTW, the entire system is stock. Everything externally looks good. Could the problem be with the reservoir, reservoir connection or mayble the master cylinder? Do I start changing out peices? Should I start with brake lines first? Does Suzuki make rebuild kits for the master cylinder and calipers?

Thanks in advance for the assistance.

Brett

 

Check the bleeders and make sure they are tight. Air can slowly seep into the system if the bleeders are not seated all the way. That and make sure the banjo bolts are torqued. Sitting for 17 days and having air in the brakes sounds like a slow leak somewhere.

 

Have you rolled the bike?

We chased a problem like this on my buddies GSXR1000...

One of the front wheel rotors was bent!!!

Pumping the lever brought back pressure... Roll the bike and the lever would go to the grip again...

Personally, I do not see how air could be liking in... More than likely it would be fluid liking out...

Look for obvious leaks on the hose connections or bleeder screws...

Remember to bleed the Master Cylinder first and then the Calipers... Once you get a firm lever bleed it a couple more times...

Report back on the Rotors... I think that may be it...

Luis

 

If it is open enough for fluid to leak out, air can and will get back in. The only way air wouldnt get back in is if pressure is being applied to the fluid at the time.

 

If you have a puddle of brake fluid by your caliper, you will know why your lever goes all the way to the grip...

If the system is full of brake fluid (Has been bled)... And there is NO apparent fluid leaks.... It is highly unlikely that atmospheric pressue would leak into the system...

Luis

 

He said after 17 days he had air back in the system. How the fuck do you think air would get into a sealed brake system if there wasnt an opening somewhere? Fluid seeps out, air gets back in. Fluid doesnt just run out of the bike without being replaced with air or more fluid.

Thats why the bleeders get closed really fast if the brakes are bled without a vacuum. If the bleeder is open enough to allow fluid out, it is open enough to allow air in.

 

I've seen many fluid systems leak air into them without leaking any fluids out. Air is a little thinner than brake fluid.

 

I had a similar issue with an '07 600RR. I found a brake rotor that was slightly warped and everytime the bike was moved, the warped rotor pushed the pads back into the caliper and the brake lever went back to the right clipon. Check out your rotors, you may find one or both warped.

 

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Had an 06 750. The stock system sucks. You'll chase your tail forever. There was a thread a couple years ago by racer dad I believe addressed the issue and fixed most peoples issues.

 

So what was the resolution?

 

Search function is your friend.

 

I think he said put a zip tie on the lever.

 

Well it was 17 days...

Brake Fluid must have evaporated into thin air... Or magicly air liked in...

Unless your enemy sneak into your garage and tamper with your bike...

Previous bike owner is playing Voodoo on your bike... Bad chuchu kachu!!!

What could it be? ? ? ? ? . . . . .

 

Has the break fluid been changed? My bike did the same thing. I changed the fluid and it fixed it. Good luck

 

Brett,

Replace the brake bleeders with "speedbleeders." This will make it MUCH EASIER to bleed the brakes. Opening and closing the bleeder can make it a pain the butt and help reduce the air that can get in while bleeding them. Check them out at speedbleeders.com.

 

Hey Craig!

 

I have found that they can let some air in.. so always do 3-4 pumps at the end with the "traditional" method.

 

I had the same issues with my 08 as well as my buddy and his 06. It's got something to do with the stock MC, they BLOW!!!!! I put an brembo R1 MC on mine and haven't had a single issue since. Just my .02

 

Use teflon tape on your bleed nipples on both calipers & mc. That's supposed to prevent air from entering when u fill up a dry system. Of course assuming that there are no leaks anywhere. While your at it upgrade to braided lines.