Help with bleeding brakes

11 replies to this topic
  • bradgross71

Posted March 07, 2014 - 10:39 AM


Putting a brake switch on my bike, I know how to bleed brakes and am sure there is no air in line. Bike is brand new. My problem Is I can not build any pressure with the brake pedal. What gives?

  • Heisenberg87

Posted March 07, 2014 - 10:44 AM


make sure you only crack the bleeder valve slightly open.  too much lets air back in the line.  grab a motion pro brake bleeder, works awesome!!! 


this vid is pretty useful



http://www.rockymoun...o brake bleeder

  • Krannie McKranface

Posted March 07, 2014 - 10:51 AM


That is the coolest damn bleeder tool I've ever seen

  • bugeye_bob

Posted March 07, 2014 - 10:57 AM


I had to recently replace a rear caliper and I used my car caliper spreader tool,
Wound the piston right out and just left the tool in place, so there is no give in the system,
Took a couple of pump and locks but spot on, no messing.

  • flyandride

Posted March 07, 2014 - 11:00 AM


Get a big syringe and a short piece of hose that fits the bleed valve.  Put teflon tape on the bleed valve threads.  Pump in fluid from the slave cylinder and tap on the brake line to dislodge bubbles.  Works every time for me.  

  • bradgross71

Posted March 07, 2014 - 11:59 AM


Found a post from grayracer about bleeding at the banjo, work great!! Thanks gray

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  • grayracer513

Posted March 07, 2014 - 01:01 PM


Rear Brake? Yup, that's where the bubbles hide.

  • bradgross71

Posted March 07, 2014 - 01:15 PM


Yes rear. Why can't you pump them out?

  • vlxjim

Posted March 07, 2014 - 01:54 PM


I use a hand vacuum pump and pull the fluid through. Make sure that you don't let the level get to low at the master. 



  • grayracer513

Posted March 07, 2014 - 02:31 PM


Yes rear. Why can't you pump them out?


Because, as I said in the post you said that you read, the banjo bolt on the rear master is a large enough volume to allow an air bubble to sit and watch fluid flow past it, and it's obviously the high spot in the system, so air is going to go there and get stuck.  Bleed in a normal manner until it looks like no more air is coming from the bleeder, then burp the banjo fitting once, and you should be done.

  • bradgross71

Posted March 07, 2014 - 02:47 PM



  • beezer

Posted March 08, 2014 - 07:55 AM


Sometimes if you push on the rear brake caliper which pushes the piston back in it moves the air bubble back through the master cylinder.


Kinda bleeding in a reverse direction.


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