2011 450 SX-F Front brake problems

My front brake lever has suddenly gotten real mushy and the front wheel sticks when rolling the wheel...I have changed the pads, bled the system numerous times and rebuilt the master cylinder....Anybody have any other ideas?????????thnx

The wheel probably sticks due a bent brake disc. Bleed the system while holding the brake caliper higher up (easiest with some help from a friend. Or an enemy..) than the master cylinder to get rid of all of the air.

Put a zip tie around the brake lever over night. Or reverse bleed the brakes.

Grease up the glide pins on the caliper. :smirk:

I go with Ville and would guess that there is a wahoo in the rotor. This makes the rotor stick when you spin the wheel, and it also forces the pads apart slightly so you get the mushy feel at the lever. Check the rotor not only for a slight bend, but also for some uneven wear on the surface. It may have gotten hot spotted and is slightly warped or has a dish to it that could cause the mentioned issues.

I have done all you have mentioned...The disc is not bent....the wheel spins as if the brake will not release the pads completely.......I am going to try a Honda CRF master cylinder to see if this clears it up..................thnx for you ideas.....

ive had the same problem, all i did was push both pistons out by pumping the lever with the caliper off and brake pads out then smeared silicon grease around the pistons then pushed them back in.. you don't have to pull the pistons all the way out just enough so the silicon grease will touch the seals.. then put it all back together and give it a whirl

ive had the same problem, all i did was push both pistons out by pumping the lever with the caliper off and brake pads out then smeared silicon grease around the pistons then pushed them back in.. you don't have to pull the pistons all the way out just enough so the silicon grease will touch the seals.. then put it all back together and give it a whirl

I don't know if i follow this , so your saying the seals are causing the pistons to stick ??? , if so wouldnt that cause the brake to drag ??? .. or am i missing something here ??/

I am asking because my friends 11 has the same mushy front brake feel and we cant figure out the cause

I have done all you have mentioned...The disc is not bent....the wheel spins as if the brake will not release the pads completely.......I am going to try a Honda CRF master cylinder to see if this clears it up..................thnx for you ideas.....

I'm running a Honda/Nissin front m/c on my SXF; better feel than the Brembo IMO.:ride:

I got tired of playing with the Brembo unit and installed one from a Honda.....all the difference in the world.............now if I can only change the wheel cylinder.......

What year Honda M/C are you running , and can you use the KTM levers on it ??

What year Honda M/C are you running , and can you use the KTM levers on it ??

The M/C was a spare I had for my XR650R (which is the same as the CR/CRFs). Not sure what year, but not that it matters, as they are all the same as far as I know.

Never tried to fit the Brembo lever on it. 99.99% sure it will not bolt on as is, but that doesn't mean that you couldn't make it fit after some work with a dremel and some patience.

Only reason I put the Nissin M/C on is that I crashed and somehow bent the banjo bolt. I didn't have a spare banjo bolt for the Brembo, but I did have the complete Nissin in my box, so on it went during a break between two motos at the GP I was racing that weekend. The Brembo M/C was still fine; I gave it to a friend of mine so he could use it for the brake on his 2-Moto snow bike kit.

Well , I took the suspension off to send it in to be re-valved ,(i had already re-sprung it , but it was still blowing thru the stroke) and while it was off , i took a old rotor i had for my Honda , and stuck it between the front pads , and pumped up the brakes and then tied the lever to the grip for the week that the suspension was in the shop (actually 3 days), and he rode it today (Sunday) , and the brakes were firm and did not fade or feel weak anymore , so that trick of tying off the lever to bleed it out seemed to work !!:ride:

Want to get rid of all the air inside the system instead than moving it somewhere else inside it ?? Do the bleeding with the caliper/bleeder bolt higher up than the MC and then bleed it.

Want to get rid of all the air inside the system instead than moving it somewhere else inside it ?? Do the bleeding with the caliper/bleeder bolt higher up than the MC and then bleed it.

I disagree here for several reasons. First there has to be air in the system as otherwise it would lock up when getting hot (fluid boiling, water). So you don't want air after the master cylinder piston, but in the reservoir an airchamber is necessary. Second, it doesn't matter where the air bubble sits (after the piston) - regardless of the postion the effect will be the same. Third, did nobody ever wonder why pressurizing the system and letting it sit over night will make a difference? In the end the effect is the same as the back-bleeding Ville is suggesting - not more and not less!

Michael

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