water pump 04 wr450

4 replies to this topic
  • twobigredneck

Posted March 03, 2014 - 08:54 AM


replaced a water pump in my 06 wr450 and is leaking out the bypass hole

  • slideleft

Posted March 03, 2014 - 08:59 AM


you have a bad seal

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  • twobigredneck

Posted March 03, 2014 - 12:03 PM


i thought so that's why i got new ones and a bearing so this wouldn't happen..

  • grayracer513

Posted March 03, 2014 - 02:14 PM


You may have an impeller shaft that has a significant groove worn in it from the previous coolant seal.  This causes the lip of the new seal to get "stuck in a rut", so to speak, and be unable to seal well.


Another possibility is that you installed the seals backward (see the picture below)


A third possibility is that your balancer shaft bearing on the water pump side is shot: http://www.thumperta...ter-pump-seals/

If this is the case, the bearing cannot be replaced with removing the engine and splitting the cases, because on the older models (pre-'07), the retainers were on the interior side. 



  • RMK800

Posted March 03, 2014 - 06:30 PM


I just did this fix. I used a water pump rebuild kit and replaced bearing and both seals. If you follow this thread they realize the book is off and can cause confusion.


Double check your seals as mentioned. After I put it together I was still nervous I didn't get it right, but no more leaks. So I'm good. If I did it again I would take pictures of both seals, just for reference and your not second guessing yourself.


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