04 WR450 Front Brakes, No Stopping Power!

7 replies to this topic
  • bterp67

Posted April 17, 2009 - 07:10 PM


My son's 04 WR450 has had terrible front brakes forever and it's getting worse. They are spongy and do not grab the rotor.
I have bled the front system countless times, from the caliper to a bench bleed, with not much change.
The stock pads were the worst. I switched to Galfer "Black"/ semi metallic and it grabs better, but not like it should. These are the best pads for my KTM, but I'm not sure what the Yamaha likes.
I noticed the stock rubber front brake hose would flex as the lever is squeezed, so I put on a stainless braided. The hose flex went away but the stopping power is not there.
I put in a master cylinder kit, bled the system and it's no better.
I've used brake cleaner on the pads and rotor, deglazed the pads, scuffed the rotor looking to get a clean bite again and nothing better.
I'm about ready to take the front master cylinder off from my old '01 KTM and try it.
Does anyone have any suggestions or better experience with these front brakes?

  • ww44wrf450f

Posted April 18, 2009 - 03:00 AM


Did you take apart the calaper, clean it all up or rebuild it?, did one side of the old pads wear faster than the other or uneven, r the pad pins smooth. With the cap of the master, apply pressure to the brake does it burp? while applying pressure?

  • init ref

Posted April 18, 2009 - 10:28 AM


After checking all the above and you still need more bite get yourself a set of sintered brake pads. The stopping power is beyond belief, really actually too much for offroad riding in slippy rocks or sand. Think one finger lockup strength.

Awesome for supermoto, tho.

  • Krannie McKranface

Posted April 18, 2009 - 02:55 PM


You have not described the problem, other than 'it's terrible'.

Do you have pressure on the lever? Does it change when you pump it?
Is there ever a time when the brakes work better (after a bit of riding).
Are you contaminating the pads? It doesn't take much handling to permanently ruin a set of pads.
What are you doing to bleed it, and how do you know you have all the air out?

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  • redhurricane

Posted April 18, 2009 - 05:14 PM


Is it possible that the pads are contaminated with fork oil? clean dry non-contaminated pads will stop very well. Fork seals good?

  • bterp67

Posted April 20, 2009 - 06:55 AM


Okay, back from the 1st enduro. now, and brakes are still the same.

Fork seal leak. Yes I did just change the fork seals because of a leak. I didn't know the pads could be contaminated because of that, I cleaned them with brake cleaner and thought this should be good. I will try a new set of pads.

I had a AA rider ride it and give me his opinion. He thinks the lever feel is great, but just doesn't grab. Back to the fork oil contamination. Makes sense to me.

Any advice on brand of brake pads? I am always willing to try something new if it works better.

  • redhurricane

Posted April 20, 2009 - 12:13 PM


Identical issue on my '06. Replaced with EBC pads, they have ok bite if dry. Wet conditions and they leave a little to be desired.

I was told you can take the contaminated pads and "bake" them in an oven to burn off the oil, but I just opted for new pads as the old ones were more than 50% gone.

  • c9buff

Posted April 21, 2009 - 05:55 AM


Anytime I get fork oil on my front pads I take them off the bike, important, and use a torch to heat them. I get the things pretty hot and it burns off the oil.



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