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Discussion Starter #1 (Edited)
First post on this web site so greetings to all. My son in law has a Jan 2008 bike with ABS II brakes. Whist changing rear disc we managed to let some air in the rear brake circuit and despite all our efforts (including using a pressure bleeding kit) we can't seem to get it all out. The symptoms are a slightly soft foot brake pedal which goes firm when the front brake is applied. What disturbs my son is the fact that when applying the front brake during hand manoeuvring the bike (i.e. ignition on but engine not running) we now hear a squelch type noise from the area of the ABS control unit whereas previously we just heard a click as the electrical actuation of the rear brake occurred. We feel sure it must be air in the ABS unit but this model has no bleeding points on the ABS units. Has anyone else had this issue (if it is an issue) and if so, and we are right in our diagnosis of air in the system, how did you get it out? Much appreciate any help/advice as we are new to bike maintenance but have many years of car maintenance experience.

Sorry - I have just been advised that itis not ABSII but a 'valve-operated system without servo assistance'.
 

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I'd try the standard "can't get the air out" tricks like holding the brakes on over night (harder with the foot lever than the hand lever, but doable) followed by another bleed. I'm not familiar with the location of the rear brake fluid reservoir on the '08 and later bikes... make sure that it is the highest point of the system as you do the work, too.

Good luck.
 

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same problem!

Hello, have you solve the noise problem? Is it caused by air in the pump or anything else likes too much pressure of vaccum bleeding device has hurted the rubble valves inside the pump?

Today I replaced a used ABS modulator to my R1200GS(2007/10, i-abs 2). After bleeding the front and rear brake(use the vaccum device), the ABS fuction recovered well without any further failure signal on the instructment cluster and I tried to hard step the rear brake lever in many times, the ABS intervene the rear tire's lock very well!

But only one issue is that I also heard clearly about a strange noise came from the ABS Pump's operation when each time the front lever is applied during rolling of either wheel(without engine running, used central stand).

The noise sounds like a gear keeps whirling inside of ABS pump and the noise lasts only 1~2 seconds. It seems like the noise related to the fuction of rear brake controlled by front lever, I can roll the rear tire until the noise comes out.

I know the ABS pump is also charge of distributing the braking power to front and rear brake clipers respectively, whether or not the noise is came from the pump valves or pump motor? I am curious about how to eliminate the noise as well!
 
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