Brake flush with GS911 questions

[Riderdrumr]

So I made the mistake of NOT knowing you need the GS911 when performing a brake bleed. Not only that, but even when I had my Honda ST1100, I just never learned the art of a smooth brake bleeding. Even with towels and such, I ended up with fluid leaking and spilling somewhere. It was probably because I was never prepared with correct containers, sequences, or general knowledge.

 

Since then, I have watched several videos (BMW specific with GS911), searched this forum and am now ready to attempt again. But here are my questions:

 

1) How much fluid do you remove on the first bleed before running the ABS procedure? The 2nd bleed before the 2nd ABS procedure? The 3rd and last bleed?

2) Do I bleed both front calipers three times?

 

I'll just start with those questions first. I'll probably have more after I get some answers.

 

Thanks!

[LAF]

My advice is buy some speed bleeders.  Be aware they are three different sizes.  Yep each front is a different size and the rear another.  That said they make bleeding brakes very easy.  If you have a helper then no speed bleeders needed but they are still nice. Speed bleeder sizes  And you buy a IV bag and life is just so easy.

 

I have changed brake fluid with and without a GS-911 and noticed no difference either way.  The GS-911 opens the ABS block to force fluid through it.

 

Yes you bleed each caliper.  Best to use a turkey baster and take the old fluid out, wipe it clean with a lint free cloth, pour new in and then bleed.

 

If you dont have a GS-911 dont hold off just because of that, do the bleed as you would any other bike being sure not to introduce air.  If you need to go for a ride and find some gravel and make the ABS kick in and draw fresh fluid into the block. 

 

Again speed bleeders and a IV bag from them and it is a snap to do GS-911 or not.  And I flush the heck out of them.  I mean you open the brake fluid bottle and you should not store it so you may as well use it all.

 

Again my on way and opinion.

[Paul4450]

👍on the speed bleeders and Lee’s procedure suggestions!

[alegerlotz]

Personally, this is what I did: 

1. Installed speed bleeders (only necessary the first time of course)
2. Emptied front master cylinder with a syringe/replaced fluid/bled both front calipers to get old fluid and any air out from installing the speed bleeders
3. Emptied rear master cylinder with a syringe/replaced fluid/bled rear caliper to get old fluid and any air out from installing the speed bleeder
4. Did the GS-911 function for bleeding the abs system
5. Cleaned up and went for a test ride

 

If you're actually changing your fluid every 2 years it is going to be clean and relatively water free anyway.  If you don't have a GS-911 and keep to the brake flush schedule I wouldn't even worry...  in this case just go engage your ABS after you bleed the system and move the fluid around.

 

Extra credit: 

If your front brake lever and/or brake pedal don't feel quite as firm as you think they should after all that, bungee or zip tie them down over night.  Any tiny bubbles of air will rise up and into the master cylinder and make everything firm.

 

[Riderdrumr]

Thanks for all the suggestions. I was able to perform flushes at each caliper, ABS purge, another flush, ABS purge, and then I zip-tied the lever to the handlebar over night. I also syringed the old fluid out before I started. After I finished, it is definitely better than after my first attempt. I have PLENTY of braking power now. I have felt other bikes where the lever is more firm, but I'm still good for now. In the meantime, I will pick up speed bleeders for the service in 2 years.

 

Thanks again! 

[Toter]

I don't use speed bleeders. I picked up a vacuum bleeder that attaches to an air compressor. About $35 at Harbor Freight. Looks like a paint sprayer. Use it to suck old fluid out of master cylinders, then add fresh fluid. At each caliper you attach and crack bleeder. Vacuum pulls fluid through. Close bleeder when fresh fluid and no bubbles. Must watch master cylinder closely. This things moves fluid quickly. Then follow GS-911 ABS procedure and rebleed all calipers. Best brake bleeding tool ever!

[Boxflyer]

When doing a brake flush, the ultimate goal is to have the brake fluid that could be absorbing moisture removed from the place where the heat of braking could cause a boiling event, and a bubble that will make braking ineffective.

 

That area, being the space within the caliper behind the pistons.  

Getting the old fluid out of the reservoir and putting new fluid in there...then cracking the bleed screws to pump fluid out of the bleeders or to draw the fluid out with a vacuum device will only put NEW fluid in the reservoir and lines, as it goes from the end of the line at the caliper right out the bleeder...not into the stagnant area behind the pistons.

 

With many of the above suggestions working hard to get fresh, uncontaminated, fluid into the system, the often overlooked step is to get NEW fluid into the area behind the pistons in the calipers.

 

So, I first install the SpeedBleeders with the old fluid doing its inevitable leaking, and some fluid draining out of the bleeder port. I like to purchase the Stainless Steel versions of the bleeders by adding SS at the end of the part numbers.  Front RH=SB8125L-SS  LH=SB6100-SS Rear=SB1010S-SS.  Normal part numbers with SS=Stainless Steel.

Then, whatever method you like, get all the remaining fluid out of the front reservoir.

Next, prior to every adding new fluid to the reservoir, I believe it's very important to do a second evacuation of the reservoir of the fluid held in the caliper body.

 

My added steps are to clean the outer walls of the brake pistons of all road crud possible, then push all the pistons (8 from both sides of the front) back into the caliper as far as possible.

This will almost fill the reservoir again with old brake fluid...repeat the removal of fluid from the reservoir that came from the static area behind the pistons within the calipers.

 

Working with one caliper at a time, I use some kind of wooden wedges ,or similar, to keep the 4 pistons of that caliper from extending when some pumping pressure is applied from the hand lever that will go to both calipers simultaneously.

 

Fill the reservoir with fresh DOT4 from a new container. 

 

With the other caliper, I open the SpeedBleeder that has the bleeder bag attached to it and note the yellowish old fluid being pushed thru the lines to the bleeder bag... while gently squeezing and releasing the brake lever.

As soon as the fluid in the bleeder hose is running almost clear, showing that it is new fluid, I close the SpeedBleeder and start to allow the area behind the pistons in the calipers to be filled with fresh, new fluid.  

On this caliper, if it was removed from the fork leg, I remount it and torque it with the 2ea. M10 bolts to 38Nm.  Now I install the brake pads with a little Silaramic Brake System grease on the contact points between the ends backing plate of the pad and the caliper. (I don't use grease or anything else between the brake pistons/pucks and the back side of the pads)

 

Recheck that the brake reservoir is occasionally topped off and not allowed to bring air into the master cylinder should it run low.

 

Now, the side that had been wedged open with some blockage to keep the pistons buried in the caliper will be bled.

Again, I attach the bleeder hose and bag so I can observe the old yellow fluid from the short section of brake line at the split on the lower fork cross brace to the caliper.

When this fluid runs clear, I close the SpeedBleeder and remount the caliper with the 2ea. M10 bolts and build up the pads in the caliper as on the first side.

Repeating the steps to now pump new fluid into the caliper to fill the areas behind the pistons and take up the space between the pads and the rotors.

 

NOW...I do the 2 or 3 interactions/steps with the GS-911 as the prompts within the program dictate, bleeding and pumping the hand brake as the on screen steps direct.

 

It takes a lot of words to describe something that might only take 10-15 minutes to complete when you are first installing SpeedBleeders...then whenever you like, but not more than every 2 years, do a manual brake evacuation and total fluid replacement by pushing the pistons back into the calipers.

 

Last step is to always pump your brake lever enough times to get the brake pads up close to the rotors...it will scare the crap out of you if you apply brakes at your first stop and nothing happens for 10-12 frantic squeezes of the brake lever...make sure you get a firm/hard brake lever before moving the bike whenever you work on the brakes!

 

I am not as emphatic about doing the steps with the GS-911 as I was when I first got my 2016 WetHead, but I do like to at least clean the pistons, force them back into the calipers to displace OLD fluid each spring and get fresh/NEW DOT4 in behind the brake pistons deep down inside the calipers.

 

[Toter]

Nice write up on the brake flush. Definitely harder and more tedious to put into words, than to actually perform. I usually clean the calipers well, then compress the pistons, inspect and reinstall pads and caliper. With the vacuum bleeder there is no need to wedge the pistons back, since there is no pumping of the lever or pedal, until all old fluid is out and new flows  through. Depressing the pistons definitely pushes old fluid back into the reservoir so it is good to compress the pistons from both calipers in the front before pulling fresh fluid in. Pumping up the calipers takes a bit of fluid, so watch the reservoir and add as needed. Following GS-911 ABS activation, I usually flow quite a bit of fluid through each caliper to ensure 100% new fluid. You can't save the fluid from the open bottle, so use it up.  Once you run through this process, it is pretty simple and you can be sure it's done more thoroughly than any other person would do it. That's what is so satisfying to me. Doing this kind of stuff is therapeutic in the man cave, but, then, I'm retired and have the time.

[K100Fran]

Don't mean to hijack, just sharing. I have a 2014 with about 11900 miles, only about 1,800 of those are mine . I didn't get service records so I figured it's time to flush the brake fluid along with a bunch of other maintenance items. I did the rear first using a turkey baster to draw some of the fluid out. I was a bit surprised to see some crystals come out along with the yellowish liquid. Closer inspection revealed a bit of crystalline sludge in the cylinder. I cleaned it out thoroughly and filled and flushed the system three times. I did the same with the front, but the front was much worse (see attached photo). I don't have a GS-911 so i couldn't perform that part of the flush. I'll go out and cycle the abs and flush each one at least 1 more time (1 quart of DOT 4 goes a looong way). I know it isn't the best possible solution but I'm confident it's a lot better than what was in there! 

 

[LAF]

Not to be ignorant but I have never seen anything like that in all my years of doing brakes on cars and bikes.  I am wondering if it was ever done?  8 years old, not driven much may make that happen.

[strataj]

A friend of mine had the same color but his turned to gel, it was so bad it had clogged the brake line.  Yep he didn't have much stopping power.   His was a 13 GS he got it less than a year old, the fluid was never changed or it was so long ago he couldn't recall.  It took a while to clear/clean it all out but all is well.  He got lucky he didn't need a new master cylinder. 

[K100Fran]

1 hour ago, LAF said:

Not to be ignorant but I have never seen anything like that in all my years of doing brakes on cars and bikes.  I am wondering if it was ever done?  8 years old, not driven much may make that happen.

Yep, kind of reminded me of something I could have pulled out of my fridge back in my single days.

[alegerlotz]

The wethead RT calls for Low Viscosity brake fluid as far as I know.  I wonder if the standard variety was used here last time is was changed...

 

Personally, I'd wipe it out best that you can and flush it a couple of times with a high quality low viscosity brake fluid.  You can always do so, ride it for a couple of months and then do it again to get any remnants of the old stuff out of there that might have clung to the sides of the lines, etc...

 

If it brakes normally, I wouldn't worry much about it.

[LAF]

21 hours ago, K100Fran said:

Yep, kind of reminded me of something I could have pulled out of my fridge back in my single days.

Well I am sure it is fine now after you cleaned it up and bleed them.

 

I bet she works well now and is very happy you found her and are taking care of her.

[K100Fran]

30 minutes ago, LAF said:

Well I am sure it is fine now after you cleaned it up and bleed them.

 

I bet she works well now and is very happy you found her and are taking care of her.

Thanks Lee. I can hardly wait to see what the final drive oil looks like!

[LAF]

4 hours ago, K100Fran said:

Thanks Lee. I can hardly wait to see what the final drive oil looks like!

Think positive thoughts.

[dirtrider]

On 10/7/2021 at 9:37 AM, LAF said:

Not to be ignorant but I have never seen anything like that in all my years of doing brakes on cars and bikes.  I am wondering if it was ever done?  8 years old, not driven much may make that happen.

 

On 10/8/2021 at 1:25 PM, LAF said:

 

Afternoon LAF

 

Up until recently I have only seen that when someone mixed incorrect brake fluid in.

 

BUT, the last couple of years I have been seeing it more & more (mostly on the BMW's that have the urine bottle reservoirs & usually on the front only). 

 

I got to thinking about this thread today as I just did a full service on a 2014 BMW 800GS &  2008 1200RT (same owner).

 

The bike has been serviced by me the last couple of brake services with dealer doing it before me. 

 

So-- same brake fluid last 2 times (same this time also), same rider, same person doing the last two services, not a lot of miles but around 1 year &  3k (give or take)  on each after first service (by me) & close to 5K & 2 years since last brake service (by me).

 

Now here is the odd thing, 

 

The 800GS (urine bottle front  reservoir) had LOTS of white crystalized crud floating around in the reservoir (took me darn near an hour to fish it all out). Rear was fairly dark yellow but  clean & no crystals or crud.

 

The 1200RT (with conventional front reservoir) the fluid looked like new in the front & just slightly off color from the rear.  

 

Not sure if it is just coincidence, or usage (more off-road on the GS), or sunlight working on the fluid in the almost clear  urine bottle reservoir, or something leaching out of the plastic reservoir into the fluid, or ??????

 

Just something to think about for the riders getting a dealer service as most dealers will just toss in new fluid & bleed as usual, I just can't see any of them taking the time to dig all that crystalized crud out not to mention even looking for it to begin with.  (that stuff floats just enough to stay in suspension, and/or cling to the sides so most won't bleed through). 

 

 

[Toter]

I think it has something to do with the fluid BMW used. On my 2014 GS and my buddies 2016 K1600, the reservoirs were full of that white goo. In all my years of motorcycles and cars, I have never seen brake fluid look like that. Even in an old 57 chevy that had lots of rust, no white goo. Here are pics of my GS, and his K.

[Skywagon]

I have seen that before in cars.  Rare but it happens.  I am almost sure  that is excessive moisture.  As a kid working in my dads shop, I probably saw this 3-4 times.  It was usually caused by the rear drum brakes taking in moisture when those little nasty pins pn the wheel cylinders on the rear would expand and contract as you pressed the brakes.  I'm not sure how that would happen on a bike.  It would be interesting to send it to a lab like blackstone and have it analyzed.  With very heavy moisture in hygroscopic fluid....it will produce crystals.

[Toter]

My 2014 GS had 14k miles when bought in 2020. My buddies 2016 K16 had 8,000 mi. at the time. My GS showed very little evidence of off road activity. The K bike was much worse. Funny thing, both brake systems worked normally. May well have faded badly under continued heavy braking,  but when we ride twisties, we try to avoid using brakes if possible.

[Boxflyer]

24 minutes ago, Toter said:

My 2014 GS had 14k miles when bought in 2020. My buddies 2016 K16 had 8,000 mi. at the time. My GS showed very little evidence of off road activity. The K bike was much worse. Funny thing, both brake systems worked normally. May well have faded badly under continued heavy braking,  but when we ride twisties, we try to avoid using brakes if possible.

Off road water is usually not the culprit with our current bikes... although it could be

 

The water that deteriorates the brake fluid is most often introduced from the normal "breathing" of the airspace within the master cylinder.  As the air around and within the master cylinder heats, expands, cools, takes in moisture laden air, the hygroscopic nature of brake fluid just keeps soaking in the suspended moisture from the air.

Finally, it gets to the point that you can see in your pictures.

When you flush your brakes, try to get all that same bad fluid out of the calipers by pushing the pistons fully back into the caliper body before starting to flush the system.  Then when the fluid runs clear at the caliper, release whatever mechanical blocking method you used to keep the pistons back so that the area behind the pistons within the calipers gets new/fresh fluid also. 

Good luck.

[cookie]

Thought it was better to latch onto this thread rather than start another on the same topic.

 

I followed Boxflyer's procedure for flushing and bleeding, as well as using the GS911 to actuate the ABS pump. Unless I'm missing something, nowhere is it mentioned that the rear brakes should be done the same way (or maybe it's just too obvious). So when I did the work today, I followed the same procedure and used the GS911 twice, once for the front and once for the rear. In each case, after two or three cycles, the GS911 indicated that the procedure was complete.

 

Correct?

[Boxflyer]

I think that’s correct. 
Both front and rear initially travel thru the ABS pump. 
Remember, there’s a revised spec to use DOT4 LV (low viscosity). 
This helps with response time of not only ABS but DTC (traction control)

[Mike279]

I have been buying Bosch 5.1 which seems to be the latest and greatest at the moment. 

[dirtrider]

1 hour ago, Mike279 said:

I have been buying Bosch 5.1 which seems to be the latest and greatest at the moment. 

Evening  Mike279

 

Are you sure that your Bosh 5.1 meets LV specs. Last can of Bosch 5.1 I used (used on older motorcycle with Bosh 5.1 fluid supplied by that bike's owner) only showed it replaced Dot 3, Dot 4, & Dot 5.1  (no mention of Dot 4LV).

 

In the testing we have done where I  work (not that I recall testing with Bosh 5.1 though) most 5.1 fluid falls part way between the Dot 4 & the Dot 4LV (closer to the Dot 4LV than the standard Dot 4 but still a couple of hundred Cs off of the -40c rating of Dot 4LV).   

[Mike279]

Bosch ESI6-32 5.1 from the label.  Seems to cover everything I own bikes, cars and trucks.

• Bosch ESI6 is the next generation brake fluid. It exceeds all current DOT standard requirements (FMVSS 116)
• First to simultaneously combine both low viscosity and high wet boiling point at its operation
• ESI coverage includes the majority of all brake systems launched since 1990; Use with DOT 3, DOT 4, or DOT 5.1; Coverage excludes DOT 5 silicone based brake fluid which is limited to military and racing applications
• Excellent lubricity properties to prevent wear of components in the brake system and reduce noise
• Longer lasting: 100% longer than DOT 3, 50% longer than DOT 4, and 10% longer than DOT 5.1 (with 30% lower viscosity)
• Wet boiling point ~ 360 DegreeF/Viscosity at -40 DegreeC ~ 685mm2/s