StromTrooper banner

Bleeding ABS brakes -- really no way to bleed the "ABS" part?

5.3K views 10 replies 10 participants last post by  pwillikers  
#1 · (Edited)
I replaced a front brake line on my '08 Wee with ABS. Now I need to fill and bleed it. Someone posted a diagram that showed how ABS works (alas, I don't have it at my fingertips, so I can't give credit :-( ), and it showed that under normal circumstances, a bunch of the tubing is closed off from the "normal" lines; the valve positions are changed only when the ABS detects skidding. My take on this is is that there is no reasonable way to drain and refill that fluid. Is this really true? And what happens if you get some air in there?

There was another posting of a technical genius who created an electronic device that would fool the ABS mechanism into thinking the bike was skidding, and actuate it at will. I think it involved an Arduino. My hat's off to that guy. I have a degree from Famous Technology University, and I couldn't come close to creating what he did. He mentioned the possibility of making them for sale, or publicizing plans or something, but as best I can tell that never happened. Oh well.

So do I just pretend the ABS isn't there and bleed the brakes as if they were normal, and carry on? Should I be doing something like bleeding it, going out and doing a lot of stops on loose gravel, and bleeding it again, or what?

Thanks!

Edit: Oh. I don't know why I didn't find this posting before, but it would seem that there's nothing special for me to do. This doesn't quite fit with my memory of the ABS diagram I saw (which, of course, was somebody's hand-drawn effort; maybe correct, maybe not). If anyone who really knows this stuff can confirm or deny, I'd be grateful.
 
#2 ·
If you really care you can sort of bleed the ABS circuit and sometimes fix ABS valve errors. Find some damp grass, get up to ~40kph, brake hard (i.e. brakes shuddering until you stop). Repeat a few dozen times then do another fluid change.

Bit nervous in my back yard as I have ~40m of grass then a gully each end but it works.
 
#3 ·
Thats how I do mine; bleed them, then take the bike out in the gravel driveway and grab enough front and rear brake hard enough to activate the ABS, then bleed them again to get rid of whatever air was trapped in the pump. I've been doing it that way for years now. I know there's a sequence on my Super Tenere where you can cycle the ABS pump while the bike is sitting in the garage, but I've never done it that way.
 
#5 ·
I bled my front brakes after putting an extension on for risers, and had no problem draining the reservoir on the handlebars from the wheel. Unless there is some fancy thing going on with re-routing through ABS, I am pretty sure its draining everything out. Just be sure you keep topping up the reservoir so you don't let copious amounts of air inside the lines, and add some speed bleeders while your at it.
 
#6 ·
The 'problem' which isn't that bad a problem is that without the ABS cycling there's fluid that stays inside the ABS lines and doesn't get flushed. If the ABS gets activated now and then it'll mix with the fluid in the lines, if you don't it can get quite nasty and cause problems.
 
#9 ·
The 'problem' which isn't that bad a problem is that without the ABS cycling there's fluid that stays inside the ABS lines and doesn't get flushed. If the ABS gets activated now and then it'll mix with the fluid in the lines, if you don't it can get quite nasty and cause problems.
I think that's the key, periodically activating the ABS so it mixes and you only need to flush it once. That is, if you stay on the routine schedule of changing it.
 
#7 ·
I too would want to completely flush at fluid change time. I did mine when I bought the bike a few years ago, it was about 6 years old then. I was surprised at how grubby the fluid was.

I see that the suzuki diagnostic system has a command to activate the motor and valves. So the answer to the OP's question is yes and no. Depends if you possess the suzuki diagnostic system.

Looking at the manual I see that the fluid is routed through the ABS HU, so regular flushing does move most of it. For the small amount remaining, I think my chosen path will be ride it and lock 'em up approach. Although my local dirt section will probably take chunks out of the tires. Ce la vie