Front Brake caliper Problem

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Lorenzo Arevalo

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Hi to all
Need your help and advise
I am have a problem with my 1997 yamaha warrior. After 10 mins of riding both front tires lock up and my front brake lever is extremely tense. After a while of letting the warrior cool down the front tires unlock a bit. I previously installed both front Brake caliper re build kit (brand all balls) but I still have this problem.

Any tips or advice?
Thank you
 
This sounds like a potential fluid contamination issue. I'll explain more after providing you with the MOST accurate steps necessary for you to self diagnose what your exact issue(s) are.

The first step will be to remove your master cylinder cover and look at the rubber gasket that is directly under the master cylinder cap. The rubber should look exactly like it did brand new. IF the rubber is swollen and/or bulging all over the place, you have contaminated brake fluid! the ONLY fluids that can EVER enter a brake system on 99% of cars, motorcycles and ATV's are D.O.T. III or IV!!! ANY other fluid will cause the rubber seals to expand many times their original size, parts to leak/seize etc etc.

IF your master cylinder gasket looks to be in tact, then drive the "bike" until you get the front wheel(s) to lock up as you described. If BOTH wheels are locking at the same time, I'm almost going to assure you of contamination....but the thing to do is to crank each bleeder screw loose, one at a time to see that doing so releases the pressure on the rotor and allows the wheel to rotate freely again. IF the wheels rotate freely AFTER cracking the bleeder screws, the first thing that likely failed would be the brake hoses themselves....now I don't have my bike here to look at how this front brake system is engineered, but I'm near certain you have a brake hose at the master cylinder and then it branches off to the left & right brake hoses. This would lead mt to start off with the brake hose at the master cylinder as the failure, as if either the LF or RF brake hose would not affect the opposite wheel if one or the other brake hoses failed.

IF there is ANY EVIDENCE of contaminated fluid, you'll be rebuilding your master cylinder and both calipers and replacing all brake hoses/any other component that has rubber inside of it!!! A contaminated master cylinder can also hold pressure on the caliper pistons, the same as a collapsed hose (internally, you can't "SEE" a collapsed hose) will do so. You have to use the process of elimination along with your eyes to diagnose the underlying issue/issues.

IF releasing the bleeder screws DOES NOT free the wheels, then you may simply have frozen front brake caliper hardware. ALWAYS clean all pins when servicing your brakes and then apply a silicone based high temperature disc brake hardware lubricant to the pins, the metal "anchors" the pads slide on etc etc. NEVER use ANTI-SEIZE where ever metal and rubber interact as that will effectively weld those parts together, causing an instant bind!

Let me know if you're able to follow these instructions to find your problem. I'm a certified <MASTER> auto & truck technician with over 30 years PROFESSIONAL experience, 28 as a business owner. There isn't much to an ATV/Bike I can't guide people to diagnose/repair as they're thousands of times simpler than today's vehicles!

Kirk Bonanny
 
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