250-500cc WR300 Rear Brake Issues

I just returned from a local Harescramble where I was in 1st place until the 4th lap, when my rear brakes became completely useless ! It had good fluid and pads, and were working great until the failure, so what gives? I had some guys tell me I might have boiled the fluid.
I have been racing 25+ years and have never had a rear brake failure, but I can say this is the first solid-rotor I have ever used.
I run Bel-Ray fluid, and have EBC pads (which are still in good shape after the fact). My own thoughts is this: put on a wave rotor, new pads and a in-line brake fluid cooler. Any of you Husky vets got some advise on this?
Thanks

there are a few threads on this already Here is what you do Zip Ty racing makes a kit which is a caliper braket with shark fin the new brakets lets you mount a rear rotor the same size as all the other Huskys have Now with the bigger wave rotor you will have great brakes also rotor bolts direct to hub no more rattle Zip Ty or Halls Cycle has them I have had zero brake problems now

Also, from the heavy rear brakers that I ride with, Motul600 is a brake saver.

Just put on a vented rotor.

Yes, you probable boiled your fluid. I've done it from time to time on all my bikes, until I went with Motul 600 and EBC carbon pads.

Remember, you're on a WR now and going a lot faster than you ever have, so you are using your brakes harder.

how much for the caliper bracket & oem 240mm(I assume?) disc ajax you know?

Thanks for the info guys! I contacted Zip Ty and they won't have any more bracket with fin made for 3 weeks (and Hall's was out of them). Since I can't wait that long (race before then), I ordered a wave disc from Race Disks in the UK! Zip ty recommended Spectro Brake fluid, as they found it has the highest boiling point, anyone used it?

I've boiled the brake fluid and lost the rear brakes on every bike I have owned.
Good brake fluid and the red EBC brake pads are a must.

I use the Race Disks from UK with the EBC X pads and Motul 600. I blue the rotor and char the pads on a regular basis, but they hang in there without fading.

I hope you made arrangements to have the disk shipped a little faster, because mine took about a month to get here.

If all goes well, the rear disk should show up in about 7 days

Ok guys, been beating my head trying to find the EBC X Pads for my '12 WR300, EBC says it should be a FA368X. I have looked at a lot of the bike shops on the internet, and some say that's the correct number for my bike, and others don't? Totally confused, can anyone tell me who they bought them from, and if my part # is correct?
On a good note, got the brake fluid cooler coming from Slavens, and my local dealer is hooking me up with the Motul 600! Hopefully I can get it all together before my next race, and I don't lose my brakes after all of this

FA208X if I remember right. I've got four pair coming that should be here Monday. Then I can verify that for sure.

I'm pretty sure that is the part number. It is listed wrong in many catalogs for some reason.

Yeah, many of them list the same pads that the newer 4T's use for the 250/300. If you use an older bike, before 2008, you can usually find the right pads. They are the same pads that older KTM's used also.

Here's a list of bikes that use that same pad:
FITS KTM:
EXC/EGS 125 (standard forks) 1994
EXC 125 (Standard forks) 1995-1999
EXC 125 (Upside down forks) 2000-2003
EXE 125 2000
LC2 125 1996-1998
Sting 125 1997-1999
SM 125 Supermoto 2000
SX 125 (Standard forks) 1994-1999
SX 125 (Upside down forks) 2000-2003
EXC/EGS 200 (Standard forks) 1998-1999
EXC/EGS 200 (Upside down forks) 2000-2003
EXC/EGS 250 (Standard forks) 1994
EXC 250 (Standard forks) 1995-1999
EXC 250 (Upside down forks) 2000-2003
SX 250 (Standard Forks) 1994-1999
SX 250 (Upside down forks) 2000-2002
EGS 300 (Standard forks) 1994-1998
EXC 300 (Standard forks) 1994-1998
EXC 300 (Upside down forks) 1999-2003
MXC 300 (Standard forks) 1994-1998
MXC 300 (Upside down forks) 1999-2003
SX 300 1994-1996
EXC 350 LC4 (Standard forks) 1994-1995
EXC 350 (Standard forks) 1996-1997
SX 360 (Standard forks) 1996-1997
EXC 380 (Standard forks) 1998-1999
EXC 380 (Upside down forks) 2000-2003
SX 380 (Standard forks) 1998-1999
SX 380 (Upside down forks) 2000-2003
Duke 400 LC4 1994-1998
EGS 400/EGS-E/LSE (LC4 Enduro) 1996-1999
EXC/EGS 400 (USD) 2000-2002
EXC 400 Racing (USD) 2000-2003
XC/EXC 400 2004-2007
LC4-E 400 Enduro 2000-2001
SC 400 (Supercompetition LC4) 1996-1999
SX 400 (Upside down forks) 2000-2002
EXC 440 1994-1995
SX 440 1994-1995
EXC 450 2003
SX-F 450 2007-2008
MX 500 1995
EXC 520 2001-2003
SX 520 2001-2003
EXC 525 2003
MXC 525 (Desert Racing) 2004
MXC 550 1996
Duke 620 LC4 1994-1998
EGS 620 Enduro/EGS-E/LSE 1996-1999
EGS-E 620 Adventure/Rallye 1999
LC4 620 SC Supermoto 2000
SC 620 Supercompetition 1996-2000
SX EXC/EGS 620 1995
SX 620 1996-1999
LC4 625 SC Supermoto 2002
LC4 625 SC Supercompetition 2002
SMC 625 2005-2006
SXC 625 2003-2004
SXC 625 2005-2006
Duke II 640 Orpheus/Titan/Lime 2001-
Duke II 640 Black/Orange 2002
LC4-E 640 Enduro 2000-2004
LC4-E 640 Supermoto 2000-2004
LC-4 640 Adventure 2001-2003
LC-4 Adventure 2004-2005
LC-R 640 Adventure R 2000
640 Duke 2003-2006
SMC 640 LC4 2005-2006
SMC 660 Supermoto 2003-2004
SMC 660 2005-2006
690 Rally Factory Rep 2007-2008
690 Enduro 2008
690 SMC 2008-2009
690 SMR 2007-2009
690 Supermoto 2002-2008
990 Superduke 2005-2009
FITS ATK:
125 (2 Stroke Enduro) 2003
250/260 (2 Stroke Enduro) 2003
250 (2T) 2004
370 (2T) 2004
450 MX 2007
450 XC 2007
Enduro 450 2007
500 Enduro 2003
500/600 Super Motard 2002-2003
500 (2T) 2004
All models 1997-1999
600 DTM Dirt Track Motard 2003
605 Enduro 2003
620 (2T) Intimidator 2004
700 (2T) Intimidator 2004
FITS BMW:
F 800 GS 2008-2009
FITS GAS-GAS:
Enduros 125/250 2000
FITS HUSABERG:
All models (fixing pin at end of brake pad) 1995-1999
All MX/Enduro models (Brembo 2 piston caliper ,260mm front disc) 2000-2008
All Supermotard (Beringer 4 piston caliper-front disc) 2000-2003
FS Supermotard (Beringer/FTE 6 piston caliper 310mm front disc) 2004
FS Supermotard (FTE 4 piston radial caliper) 2005-2008
FITS HUSQVARNA:
CR 125 1995-2004
SM 125 1998-2000
SM125 S 2002-2009
WR 125 1995-2009
WRE 125 1993-2000, 2002-2009
CR 250 1995-2004
TC 250 2002-2003
TE 250 2002-2005
WR 250 1995-2005
TE 350 1995-1997
WR 360 1995-2002
SM 400 R 2002
TE 400 2002
TE 410 1995-2000
TE 410E 2000
SM 450 R 2003-2006
TC 450 2003
TE 450 2003-2005
SM 510 R 2005-
TC 510 2004
TE 510 2004-2005
SM 570 R (4 bolt front disc) 2001
SM 570 R 2002-2004
TC 570 2002-2003
TE 570 2001-2004
LT 610 (6 bolt front disc) 2000
SM 610 (6 bolt front disc) 1998-1999
SM 610 R 2000
SM 610/S (4 bolt front disc) 2002-2006
SM 610 S (Radial caliper) 2006
SM 610 IE 2007-2009
TC 610/E 1995-1999
TC 610 2000
TE 610 2000
TE 610/E 1995-2000
TE 610 E 2002-2003
TE 610/IE 2006-2009
SMR 630 2006
STR 650 CRC 2007
FITS T.M. DIRT BIKES:
MX Models 85/100 2002-2003
FITS VERTEMATI DIRT BIKES:
495 1999-2002
C 450/500/570 (MX) 2003-2004
E 450/501/570 (Enduro) 2003-2004
S 450/501/570/E (Super Motard) 2003-2004
SR 450/SR 600 Motard Racing 2003-2004
FITS VOR DIRT BIKES:
SM-E 450/530 2004
MX 450/530 2004
EN/EN-E 450/530 2004

Hey Motorhead, where did you get the compatability list from? Thanks also for the help!

cyclebrakes.net

No problem.

Ok, I give. I have been dealing with fading rear brakes for awhile and have changed the fluid, changed the pads etc and still having issues. I am sure I boiled the fluid on a track day this spring and so changed fluid and pads but on a trail ride this weekend my rear brakes went away again.

I just ordered a galfer vented wave rotor that is supposed to fit my 09 wr300. My question is does this disc mount to the wheel differently i.e. different bolts etc.?

I know the stock one is kind of unique because it "floats" or more accurately rattles back there so I am not sure if I have to change anything for this new rotor.

I should have the rotor this week and I am trying to avoid any delays because I am anticipating being able to go on a ride this weekend!

What fluid and pads are you using?

Are you sure you are getting the air out of the system?

Are you purging the system until you get good clean fluid out the bleed?

I'm not sure about the Galfer rotor, it may use the stock floating mounts. If not, I'd say it will come with bolts.

I am using ebc pads and motul fluid. I am trying my best to get
the air out and I keep coming back to thinking I have blued my
rear disc.

However the one thing that pops in my head right now is that I
layed my bike over last weekend to wash it. Maybe air got in
it then?