2010 brake bleeding

I have been cleaning up the callipers and bleeding the brakes on my 2010 GSA as the old fluid was looking dark. I have done the front first and have now done the rear and the levers are much firmer now as the front was a bit spongey.

I have read that the linked brakes work in such a way that the front brake also actuates the rear calliper but the rear only does the rear. I am thinking I should bleed some more fluid through the rear bleed nipple while pumping from the front lever to flush out the fluid in the tube that links the two systems.

Whenever I change the fluid in my 2009 GS, I pump about 1/2 litre through from each reservoir and then spin the ABS motor using a GS911 for each brake. I'm not sure how much fluid will be in there, very small I would expect. Make sure that the ignition is switched on to power the ABS.




















.

Cheers part of the reason I went for a 2010 model was that I wouldn't have to use a GS911 to bleed the brakes as I have read its a pass through system, although actuating the ABS system does sound a good idea if a computer is available. I am interested to know how the linked brakes work and if there is a diagram. I will get the bike on the centre stand with ignition off and see if the front brake stops the back wheel to start with.

GrahamWebb said:

Cheers part of the reason I went for a 2010 model was that I wouldn't have to use a GS911 to bleed the brakes as I have read its a pass through system, although actuating the ABS system does sound a good idea if a computer is available. I am interested to know how the linked brakes work and if there is a diagram. I will get the bike on the centre stand with ignition off and see if the front brake stops the back wheel to start with.

Click to expand...

It wont as the ignition needs to be on to power the ABS unit which then diverts fluid through the unit to pressurise the line down to the rear calliper. Give it a go with ignition off and then on.

Ahh ok thanks so the abs unit controls it, and there was me imagining a simple hydraulic system with a check valve to divert some of the fluid to the rear calliper. At the minute the brakes are much firmer after bleeding except for a tiny little squelch that comes from under the tank.

I also read that you don’t have to use the GS911 to cycle the ABS on my previous 2011 GS TU. My brakes ended up with less travel at the lever, feeling wrong. They worked but didn’t feel right. I did them again using the GS911 cycle and all was well. So the following time I did them I used the cycle and again and they were right first time.

FWIW.
The linking of the brakes are performed by the ABS only, meaning there is NO connection between the front and the rear brakes. When the front brake is applied, the rear brake circuit is being pressurized by the internal ABS motor, and the rear brake pressure is applied as needed depending on the front brake pressure. The ABS unit has internal pressure sensor that provide feedback to the ABS computer.

Also, the GS-911 procedure that cycles the ABS motors and used when bleeding the brakes is a procedure that was used for the earlier ABS system. After 2007 when the none-servo system was introduced, the procedure was no longer needed.
The earlier ABS systems where plunger type, simply explained it may be regarded as an analouge mechanical regulator. From 2007 and on the ABS system is controlled by solenoids, and when no anti block function is activated, the brake fluids are merely passing through (as already mentioned in posts above).

To sum it up.
Bleed the brakes as if no ABS existed, and even though it may still be possible to run the ABS motor, it serves no purpose (but does no harm either).

What may be a good idea though is to remember to push the prakepads appart for the front brakes before bleeding, as the banjo and bleeder are both installed on top of the caliper, and pressing the pads apart will ensure that there is no old brakefluid remaining at the bottom of the caliper.

Thanks I realised that about the abs, with the bike on the centre stand and the ignition off the front brake has no effect on the rear wheel. With ignition on if I spin the rear wheel with my hand and apply the front brake the abs buzzes and stops the back wheel. Its good to know that I don’t need the GS911 but I guess someone could do what I just mentioned to cycle the abs pump if they wanted to.

Yep when I bled the brakes I first bled a bit through then pumped out the pistons and cleaned them all up before pushing them back in and bleeding fully. I tried to let some fluid pump through without building pressure so the pistons wouldn’t move out with the first presses of the lever. Especially on the back one it looks like if that wasn't done all the old fluid would stay in the calliper as the bleed nipple is on top of the banjo!