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I rode the wifes 02 the other day and the front brakes went to crap. The problem is that the front end went through a GSXR makeover and I dont know what year.
So how do I see if the master cylinder is shot or if I just need pads. I is full of fluid.
Help, as I am ignorent in this area.
 

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Shouldn't be the master cylinder... if that was shot I'd think it'd be leaking brake fluid all over. Is there no feel in the brake lever, or is it firm but just doesn't stop? If you can squeeze the brake lever all the way in then you will first need to bleed the brakes. If the lever is firm then check the pads. If you have decent amount of brake pad material then you might have stuck pistons and need to clean and rebuild the calipers (just rubber seals maybe)
 
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When is the last time the brake fluid was changed? Might be time. Fresh fluid every year or two will help to ensure the brakes perform well.
 

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You pull the lever and nothing happens. You see no brake fluid leaking out anywhere. The likelihood is that the fluid is bypassing the plunger in the master cylinder. A common cause of deteriorating rubber parts in braking systems is old fluid. Any fluid that is more than 2 years old can do a number on the rubber parts. Note CAN, not WILL. It depends on how much moisture the fluid has absorbed.

Old fluid will definitely make the brakes spongy, also. Changing old fluid makes a much bigger difference to brake feel than going from rubber to SS lines.

Check the calipers to see if there's anything leaking there, rub down all the lines to make sure nothing there is leaking. Can't be too careful when it comes to brakes.
 

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I rode the wifes 02 the other day and the front brakes went to crap. The problem is that the front end went through a GSXR makeover and I dont know what year.
So how do I see if the master cylinder is shot or if I just need pads. I is full of fluid.
Help, as I am ignorent in this area.
Even with bad pads, the bike will still stop, they'll just make a gawdawful racket while they destroy your rotors. You probably have either air, water, or both in the lines.

Look at the pads in the calipers. On the rotor side of each pad, you'll see a groove. As long as that groove is there, there is life in the pads. If you see no groove, replace the pads.

Flush your lines. It's easy to do. Once you're done flushing the lines, they'll probably still be soft. More than likely because of air at the master cylinder.

To remove that air, let the bike sit for a day or two after flushing it. The next step can be done with one person, but two make it easier.

Squeeze the brake lever until it bottoms out. HOLDING A RAG UNDER THE BANJO BOLT ON THE MASTER CYLINDER, loosen the banjo bolt (it's either a 12 or 14mm bolt). Retighten it BEFORE you release the brake lever.

Repeat this four or five times and you should get all the air out.
 

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If you have plenty of pad materiel, have new brake fluid and have performed a good brake bleed then it is most likely your master cyclinder. A master cyclinder rebuild kit will replace the seals preventing the blow by of brake fluid which old, worn seals will allow (reducing your braking performance). A sticking caliper piston will be easily detectable by raising the front end of your bike, spinning the front wheel, engaging the front brake and releasing it. If the wheel can be agian spun freely (there will usually be brake pad drag sounds) then the pistons are okay. If it is near impossible to move then a sticking piston is present. Caliper grease applied to the piston will cure this problem (you should remove the piston entirely from the caliper to inspect for corrossion and to inspect the full surface area of the piston).
 
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