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scorpion4664

Brakes Locking up 2008 Yamaha YZ450F

7 posts in this topic

New to the site having trouble finding link to my brake problem .

I just bought a 2008 Yamaha YZ450F and the brakes lock up .

They locked up on the test ride witch was almost very bad ,but i save it :banana:lol

I released the pressure and when the bike cooled down the bakes seem to work fine. On my next test ride i was careful not to touch the front brakes and with in a mile with not touching the brakes they locked up and i had to release the pressure .Iv pulled the calipers off and have the calipers apart doing a complete rebuild but should i be looking at the master as well . I guess im wounder if anyone knows whats causes this . I thought maybe water but from what iv read water dose the opposite and makes your brakes fail ?

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New to the site having trouble finding link to my brake problem .

I just bought a 2008 Yamaha YZ450F and the brakes lock up .

They locked up on the test ride witch was almost very bad ,but i save it :banana:lol

I released the pressure and when the bike cooled down the bakes seem to work fine. On my next test ride i was careful not to touch the front brakes and with in a mile with not touching the brakes they locked up and i had to release the pressure .Iv pulled the calipers off and have the calipers apart doing a complte rebuild but should i be looking at the master as well . I guess im wounder if anyone knows whats causes this . I thought maybe water but from what iv read water dose the opposite and makes your brakes fail ?

What do you mean release the pressure? On what?

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I'm not a mechanic by any means but did you check to see if your rotor is bent? I would think that would make the caliper work and heat the fluid causing it to expand and lock the brakes up? Again I'm no mechanic, just something to check.

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There is a return port in the master cylinder that keeps this exact thing from happening. It allows the fluid to return to the resivior as it heats up from use. The first little bit of lever travel closes off the port and allows the brakes to build pressure.

Check to make sure the lever isn't damaged, (or the wrong one) and check the fluid level isn't too high. If the lever is adjustable, make sure there's enough free play before it contacts the master cylinder "plunger".

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There is a return port in the master cylinder that keeps this exact thing from happening. It allows the fluid to return to the resivior as it heats up from use. The first little bit of lever travel closes off the port and allows the brakes to build pressure.

Check to make sure the lever isn't damaged, (or the wrong one) and check the fluid level isn't too high. If the lever is adjustable, make sure there's enough free play before it contacts the master cylinder "plunger".

ok ill check for that and the rotor is not warped i did check that . thanks for the help

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if i remove the resivor cap and remove the brake line from the caliper ,should fluid run freely out of the resivor? Iv also took a better look at the rotor and it does have a very slight warp ,Im guessing the tolerance like every thing else on a bike is critical. Can this be fixed or does it just need to be replaced .

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Bought a bleeder today done 15 mins later

Napa Auto parts 25.00

same exact one Cycle Greer had for 52 .00

so either Napa auto store doesn't know how to run a successful business or cycle gear is ripping

thanks again for the response

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