Refilling the brake system

[Wild Pig]

Ok, so a few months back the ABS module on the GS croaked. Finally got around to getting it rebuilt by Module Master (good quick service, and 10% the price of a replacement btw). Got the unit in the bike and am putting the fluid back in starting with the rear circuit. Figuring I needed to do a change anyway, I emptied out the circuits before taking the module out of the bike.

Filled the res and began pumping the brake pedal as usual for a regular bleed. Got about 1 refill into it and now can't build pressure and, pump as I may, the level won't go down in the res. Checked all the connections, no leaks. Put the miti-vac on, will pull a vacuum but doesn't seem to pull fluid. Spent the better part of two beers trying to reason it out, and another beer and a half searching the interwebs for an answer. Lot's of posts on those god-forsaken abs servo brakes, but....

Whattami missing, something obvious?
Not being patient enough and need to pump the pedal 5000 times instead of 2500?
Anyone refilled an entirely empty circuit have any tips?

[Georgeinva]

The pump bleeders (control circuits) are not quite intuitive. Looking at the pump you will see two clusters. A front group and a rear group. To bleed the front circuit start with the tall front bleeder, then the short front bleeder now go to the angled bleeder of the REAR cluster. For the rear circuit tall rear, short straight rear and angled FRONT. The angled bleeders are the integrated circuits. It may take several bleeds to get all the air out. The GS911 has a bleed test. If the you fail the test let the bike sit several hours before rebleeding.
Good luck.

[Wild Pig]

Hi George,

Thanks for the reply. The pump I replaced is the non-servo version on my 07 12GS. There are no bleed valves on the pump itself, so I was assuming I was working with just two circuits, front and rear.

[Georgeinva]

Jim,
It would help if I read before answering.
No secret handshake on the IABSII. Bleed it let it sit rebleed it. If that does not work you will need a GS911. The GS911 will run the pump and you will squeeze the lever/ push the pedal. This will dislodge the air from the ABS unit. It can be done without the GS911 but I will not put process in writing, it is not safe at all.

[Wild Pig]

Gotcha.

So, I guess what's throwing me is that the fluid doesn't seem to be moving and I can't build pressure with the pedal. It's not that I can't get air out, I can't get fluid in.

[Georgeinva]

Try removing the lines from the master to the pump and use the vacuum to pull the fluid to the pump. That is to say put the vacuum line on the steel line that screws into the pump. It can be tough to get things started.

[Wild Pig]

Gave that a try. Got fluid to the pump, still having a devil of a time getting fluid thru the pump.

Hear lots of "guishy" noises in the pump when I pull the lever. Still no fluid movement from the reservoir. I tied the lever to the grip and going to try to gravity feed it overnight. Failing that, I may try to push fluid up from the calipers.

[Genen8kua]

You would be really annoyed if the rebuilder sealed an opening with some sort of cap or plug and you hadn't noticed (and removed) it. Just sayin'. I'm thinking it's unlikely as such things usually use the same threads you need to attach the lines.

[Wild Pig]

So, today I decided to start over from the beginning and.....success!

I've narrowed the issue down to the following equally plausible explanations:

1. I somehow had something hooked up wrong. Four lines into four holes is the kind of thing that would perplex me.

2. Gunk in the pump from the rebuild.

3. Trapped air pockets.

4. Combo of any or all the above.

So, big lessons learned: be patient, when you're stuck, stop, have a beer, and start over from where you weren't.