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Front Brake issues

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Hey guys chasing some front brake issues and running into a bit of a dead end here.

2016 yz450fx

Had a fork seals leak a while back and it for sure leaked a bit on the rotor. Cleaned everything off with brake cleaner in the field and it helped a bit. When I got home I sanded the rotor and pads and that seemed to help a bit. Fast forward a month or so and I still just don't have the braking performance I use to have. 

I've also bled the brakes multiple times with no real improvement.

I'd say my braking power is about 50%. The lever doesn't have a firm feel to it either, pretty vague. But not sponge.

Any ideas? Already running a Galfer stainless line.

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Hey guys chasing some front brake issues and running into a bit of a dead end here.
2016 yz450fx
Had a fork seals leak a while back and it for sure leaked a bit on the rotor. Cleaned everything off with brake cleaner in the field and it helped a bit. When I got home I sanded the rotor and pads and that seemed to help a bit. Fast forward a month or so and I still just don't have the braking performance I use to have. 
I've also bled the brakes multiple times with no real improvement.
I'd say my braking power is about 50%. The lever doesn't have a firm feel to it either, pretty vague. But not sponge.
Any ideas? Already running a Galfer stainless line.

Put new pads in

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In case you missed it PUT NEW PADS IN. Also, if you have been attempting to bleed the brakes, maybe you got some air in the lines? That is the only thing that would explain a lever that does not get hard/stop solid once the pads engage.

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1 hour ago, blbills said:

Forgot to mention I tried new pads already.

Any oil on the rotor or pads will contaminate both.

To clean the rotor use spray brake cleaner and 000 steel wool, or green Scotchbite.

To clean the pads, remove them, throw them away, and replace them.

When you put in new pads you need to SEAT them to the rotor, before they get a flat spot with glazing. https://ebcbrakes.com/articles/motorcycle-bed-in/

If you lever is not firm, remove the front wheel, and compress the pistons fully (do not force) with something flat and a c-clamp, then bleed after.

After re-assembly, burp the banjo fitting at the top of the line i, near the bars, and re-bleed again. Air gets behind that banjo and nothing will get it out short of continous vibration on the line and lots of bleeding over and over.

When you re-install the pads make sure you put copper grease on the backside, and that you get that spring clip in nice and tight.

 

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28 minutes ago, THE KRAN said:

...burp the banjo fitting at the top...

 

What do you mean by this? Perhaps I'm missing something.  Will try a new set of pads.

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17 minutes ago, blbills said:

What do you mean by this? Perhaps I'm missing something.  Will try a new set of pads.

There is a hydralic connection at the top of the hydralic line called a 'banjo' fitting. Air gets trapped inside, and if you loosen the fitting and agressively wiggle the line (do not pull in on the lever) you can possibly remove some trapped air.

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I usually take the master cylinder top off, crack open the bleeder on the caliper and just let it drip. Never let the master run dry and use motul 600 brake fluid. Refill the master cylinder about 5 times until you know for sure all the bad stuff is out of there. It is expensive but really is the best stuff out there for dirt bike brakes.

Sent from my SM-G900V using ThumperTalk mobile app

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The right tool makes all the difference.  Forget all the make shift fixes.  Get yourself a hand held brake bleeder for $40 at Walmart, Auto-zone, O'reillys etc. 

https://www.walmart.com/ip/Mityvac-MV8000-Automotive-Tune-Up-and-Brake-Bleeding-Kit/23209395?wmlspartner=wlpa&selectedSellerId=1148&adid=22222222227017322785&wl0=&wl1=g&wl2=c&wl3=51804941831&wl4=pla-83207750951&wl5=9031565&wl6=&wl7=&wl8=&wl9=pla&wl10=112562587&wl11=online&wl12=23209395&wl13=&veh=sem

This makes it easy to flush your brake lines and quickly remove any air when doing brake work.  DOT 4 brake fluid should always be used because it has a higher boiling point than DOT 3.  Once your system is bled properly you should not have any soft or spongy feel with a steel braided brake line.  If you do, you may need a master cylinder rebuild kit.  They are about $30 from Rocky Mountain ATV (part# 5 on the schematic) https://www.rockymountainatvmc.com/oem-schematic/2 but you can check other online retailers.  I picked up a 2013 RMZ450 that had stock brakes on it and the fluid was black as could be.  I put a steel braided brake line and galfers oversized front rotor on but it still felt mushy.  I did the master cylinder rebuild and she's smooth as silk and stops like a beast now. 

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