How-to: bleed your brakes the non-conventional way

It happens to all of us: you follow the directions in your well-meaning shop manual and they tell you to take apart an assembly you don’t actually need to disassemble right now and before you know it you have air in your brake lines! 

What? Doesn’t happen to everybody? Well, it happened to me. And should you, dear reader, find yourself with the dreaded air-in-the-brake-lines such that your brake lever or pedal has no effect whatsoever on your bike’s motion, you’re gonna have to bleed your brakes. 

This sounds painful. In point of fact, I found it be a bit of a pain in the you-know-where. But here is an unorthodox approach I worked out by trial and error that might save you some grief…

Tools needed: 
  • Screwdriver (in my case Phillips) to open the brake fluid reservoir
  • Box wrench (in my case 8mm) that will fit your bleed valve
  • Assorted rubber tubings and vacuum fittings, available at your auto parts store
  • One “vacuum gun” - essentially a giant steel string that can be used to pull a vacuum on your brake lines or to push fluid into them, which can also be found at your everyday auto parts store. 

STEP 1: refresh your unit with fresh brake fluid

It never hurts to change out your brake fluid for fresh, and since you are going to be pulling/pushing brake fluid through your lines, this is as good a time as any. 

Take the top off of your brake fluid reservoir:


On my 2009 V-Strom 650, this also requires removing a plastic pressure cap and a rubber diaphragm:





Empty your reservoir of old brake fluid if necessary and then refill it with fresh brake fluid:


My bike requires DOT4 brake fluid, so I used a synthetic DOT3/4 blend (3 and 4 are allowed to mix, 5 is not).


That’s the easy part, but it brings us to…


STEP 2: bleeding top-to-bottom

Locate the bleed valve on each caliper you need to bleed. Give it enough turns with your wrench for fluid to drip out or for it to be fairly loose. Finger tighten to stop the leaking. 


Rig up your vacuum gun so that the “gun” is connected to the clear plastic hose it comes with and that hose is connected through whatever adapter you were able to purchase down to a short length of vacuum tubing that fits tightly over the nipple of the bleed valve. 

Pop the vacuum tubing onto the bleed valve as shown here:



Turn the bleed valve with your box wrench (or by hand if you finger-tightened it as suggested previously) and then begin to *slowly* apply suction to the line with the vacuum gun:





You should see some mixture of old “dirty” brake fluid and fresh brake fluid come through the line, and hopefully several of those pesky air bubbles you are trying to get out of the calipers:


Keep pulling until only clear fluid flows through. Pause every so often to refill the brake fluid reservoir so that you don’t draw any new air into the system. 

Repeat for each other caliper you are trying to bleed. 


That was the hard part. Unfortunately, if you are like me, it may not be enough. A stubborn air bubble at the top of the brake line was just not coming out and kept me from applying any pressure at all with the brake lever. 

Which required…


STEP 3: bleeding bottom-to-top

This time you will start with the vacuum gun pulled all the way out, as shown below, and pre-filled with some amount of brake fluid, maybe a quarter to a half cup. Tighten the vacuum gun seals and all tubing connections as best as you can. 




Hold the gun (not shown - sorry, ran out of hands!) so that brake fluid flows down into the clear plastic hose and the vacuum tubing. Tap the vacuum tubing and hose to dislodge any stubborn air bubbles: you don’t want to push any more air into your brake lines!

Push the plunger on the vacuum gun *slowly* to force brake fluid into the bottom of the brake lines. This will flush the existing brake fluid – and any air bubbles trapped within – up into the reservoir. 

The fluid, in my experience, moves *slowly*. There is something in the nature of brake fluid, perhaps, that does not like flowing bottom to top!

Again, repeat for each caliper you are trying to bleed. 


You should now be able to squeeze the brake lever / step on the brake pedal and get the satisfying response of feeling the brake grip. 


Last step: get out your torque wrench and check your shop manual for the desired setting for each caliper’s bleed valve. Torque it up to the desired spec and you are ready to ride. 



That is, if you can manage to get the brake fluid stains out of your jeans:



Happy trails!

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