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6th gen ABS Brake Fluid Change Guide

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Replacing the brake fluid in my ABS model--that was really something. There are no less than 7 bleeders! It took 3 people to do it. The first person operated the level/pedal and refilled the reservoirs as required, the second person opened/closed each bleeder in succession and the third person was required for the one bleeder that required manually pumping the second master cylinder on the left front brake. I will definitely be looking into SpeedBleeders or Stahlbus Bleeders for the next time to simplify the process.

In the meantime, I thought I'd document the procedure I came up with for doing the brake fluid change. The Service Manual has a few errors in it e.g. tells you to remove and tilt up the fr. left caliper but never tells you to reinstall it and it tells you refill and reinstall the lever reservoir cover but then goes on to bleed a few more bleeders that use fluid from that reservoir. There's been a lot of posts about what the correct order is and people having problems with spongy brakes which turned out to be because they forgot a bleeder or did it in the wrong order. The following system worked very well for the two 6th gen ABS models I did last fall. It's not a tutorial per se; there's no pictures and no details (for that, you can look up the excellent HS pictorial-based tutorial or the new Jay-D tutorial) and I didn't include obvious steps like removing the seat etc.


Note: although recommended in the FSM and elsewhere, I don't remove the front left caliper for fluid replacement—only when I need to bleed air which is normally not required for fluid replacement. I just manually actuate the SMC with the caliper in place. Works well and you don't risk wearing out the mounting bolts or squeezing the pads together making reassembly difficult. In fact, I don't remove the rear wheel or the rear caliper anymore either!

I made an overall hydraulic system picture by combining elements of several pictures from the Factory Service Manual:


This took a lot of image manipulation to create but it was worth it. This overall view of the braking hydraulic circuit helps to visualize how the system works. For example, it clearly shows that the Second Master Cylinder (SMC) is refilled from the rear reservoir with the pedal.

These are the steps you need to take:

- Turn handlebar all the way to the left to level Lever Reservoir
- Open Lever and Pedal Reservoirs
- Remove old fluid from Lever and Pedal Reservoirs
- Fill Lever and Pedal Reservoirs with new fluid

- Remove the rear wheel (not necessary!)
- Remove Rear Brake Caliper and install on top rear of Rear Brake Disc at 10 o'clock position (not necessary!)

- Maintain fluid level in both Reservoirs at all times, check between steps below


Operate the Lever during bleeding of the initial two bleeders in the following order:


Lever Brake Line: Master Cylinder to Front Brake Caliper

[1] Left Front Brake Caliper outer (upper) bleeder (use Lever)
[2] Right Front Brake Caliper bleeder (use Lever)


- Refill Lever Reservoir as required to Upper Level Mark
- Close Lever Reservoir (done with this reservoir)

Servo Brake Line: Second Master Cylinder to Servo Proportional Control Valve
NOTE: this bleeder (even if it's a SpeedBleeder) must be closed after each manual activation of the SMC;
[3a] open Servo Proportional Control Valve bleeder (left/battery side)

[3b] manually actuate Second Master Cylinder at Left Front Caliper
[3c] close bleeder (if you don't close the bleeder or SpeedBleeder on SPCV, the rear pedal will not force (refill) the SMC back out very effectively)

[3d] use Pedal to recharge Second Master Cylinder (SMC)

repeat [3a]-[3d] several times

Servo Brake Line: Rear Proportional Control Valve to Rear Brake Caliper
[4] Rear Brake Caliper Center bleeder (use Pedal)

Operate the Pedal during bleeding of the remaining three bleeders in the following order:
Pedal Brake Line: Rear Master Cylinder to Rear Proportional Control Valve
[5] Rear Proportional Control Valve (right side) bleeder (use Pedal)

Pedal Brake Line: Rear Proportional Control Valve to Rear Brake Caliper
[6] Rear Brake Caliper Outer bleeder (use Pedal)

Pedal Brake Line: Rear Master Cylinder to Left Front Brake Caliper
[7] Left Front Caliper Center bleeder (use Pedal)

- Reinstall Left Front Brake Caliper (if removed)
- Reinstall Rear Brake Caliper using new mounting bolts: 2 X 90131-GAA-000, BOLT, FLANGE (8X25) (torque 23ft-lbs) (if removed)
- Refill Lever and Pedal Reservoirs as required to Upper Level Marks
- Close Lever and Pedal Reservoirs

- Reinstall rear wheel (torque 80ft-lbs) (if removed)

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  • 3 years later...
  • 3 months later...
  • Member Contributer
58 minutes ago, KevCarver said:

I had to replace the secondary master cylinder on a 2003 ABS. What's the best way to get the system bled after that? 

My recollection is that the SMC gets fed from the rear MC and then feeds the rear PCV. If you fill the rear MC with fluid and then open the bleeder at the SMC to get fluid there by pushing down the rear brake pedal. Then open the rear PCV bleeder (closing the SMC bleeder) then trigger the SMC to feed fluid to the rear PCV. You will need to switch between the rear pedal and SMC to keep the fluid flowing from rear MC to SMC to rear PCV. Once fluid had filled the lines, follow the bleed process. That's how I recall doing it when I replaced my lines with SS lines.

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I don't know. My thinking is that there are two bleeders on the left caliper. One for the front MC, and the other through the PCV from the rear. The SMC draws from the rear reservoir and is bled through the top bleeder on the rear caliper.

Wera803 said it takes two people (I'm currently only 1) to push on the rear pedal and also the SMC in sequence. And I believe to bleed from the top bleeder on the rear. And to bleed the PCV after that.

I get solid fluid from the PCV. 

Rear top bleeder is very air-y, but I'm also using a power vacuum bleeder which doesn't lend itself to clear evaluation of the fluid that comes out and how much air is sucking past the nipple from outside. Except from the PCV, every linked bike I've bled has solid fluid from the PCV.

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There are two bleeders on the left caliper and correct, one is for the front MC and the other is for the rear MC. The PCV will be bled from the SMC being activated. The first time I did this I was sitting on the right side of the bike and pushing the rear pedal with my left hand and while the front left caliper was off the fork, I would trigger that with my right hand.


I recall the process was, push rear pedal down and hold it there. Then push SMC to push fluid to PCV.  Release SMC, then release rear pedal and start process over again. Of course doing this with traditional bleeders would near impossible solo but I had put speed bleeders on so it was much easier. When helping a friend with his, he manned the bleeder open/closing while I handled the pedal and SMC. The other thing that I just realized, is that the ABS models have two PCV bleed points, the 5 & 6 Gens that I dealt with only have one PCV to bleed. 

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I saw in Miguel's original 6th Gen bleeding post that there was a PCV bleeder on the left in front of the battery. I only thought there was one on the ABS and it was moved to the right. Now I see there are two. I'll have to give that one a shot too.

I was leaving the rear top bleeder open with the power vacuum on and trying to hit the pedal by reaching under the bike and SMC with my foot.

So, I'm thinking by reading your description I should be on the PCV by the battery with the vacuum line while doing this? Every time I tried bleeding the right side PCV it was solid fluid.

I'll give it a shot at least. Maybe I can round up a helper later on. 

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