[Jack Smoke]

I picked up my new to me 2016 R1200 GSA last November and during the test ride it had the spongy brake feel. Since the dealer isn't a BMW dealer, no proper service was done, the head mechanic adjusted the position and said "That's how BMW's are" I'm reasonably handy and know some really good mechanics, so I figured I could get it sorted. Well, I haven't. but I did put 8,000 miles on the bike in 3 weeks and at no point did I feel unsafe with spongy brakes. Now that I'm back and have some time to mess with the bike, getting rid of the spongy feel is not as easy as I thought. First I started with fluid flush and all 3 sets of pads. The rear went smoothly. Standard bleed, GS911 ABS bleed, standard bleed. Perfect, matter of fact, It's even tighter than before. But the rear was never an issue.

The front flush, fill and pads are a different story. Please learn from my mistakes, although, I'm not done yet, I think I figured out where I went wrong.

1. During the front pad change I reused the slider, keeper spring and retainer clip. There was a little corrosion, but over the coarse of my lifetime of changes hundreds of pads on dozens of cars, trucks and motorcycles, it didn't seem that bad. I was wrong

2. When I took the old pads off and compressing the pistons inside the caliper, I noticed one piston didn't retract completely. I figured it would pop back into position during the bleed process. I was wrong

3. I use a manual vacuum bleed system, its worked on every vehicle for years. I was wrong

4. I don't have an 8mm wrench, so I used a small channel lock pliers. I didn't break any thing, but I was wrong

5. I'm considering Speed Bleeders, but the forums are mixed on the usefulness. Jury is out.

ln conclusion. There are no shortcuts to bleed this bike. In reading a bunch of forum posts, it seems skilled mechanics and trained BMW dealers can make a mess of bleeding the brakes. It seems the key to doing this properly is patience and attention to detail. It can take 20-30 lever pulls to bleed each caliper. New mounting hardware, new crush washers, cleaning the caliper piston boots. At every step, if there is a option for new hardware, use it, if it can be cleaned, clean it. use the zip tie technique as many times as needed, and vary the bikes stance (24 hours on the kick stand, 24 hours on the center stand or longer) properly torque everything.

Lastly, if being OCD doesn't work, then I'll rebuild the Master Cylinder and both calipers. But, I'm 90% sure attention to detail will be enough.

I'll follow up with my results, but my Sunday will be spent redoing everything....the right way this time

 

[bosnjo]

Nice write-up. Keep us informed of your progress.

 

[Jack Smoke]

To be completely accurate, I found out my brake replacement hardware mistake a few days ago and replaced that. Unfortunately, that didn't fix the piston or the difficulty in bleeding the brakes.

Onto todays adventure...
Early this morning I ordered the Speed Bleeders, so I didn't see a reason to take the calipers off or do a deep dive into the brakes. I did do another bleed with proper tools and the ABS bleed as well. This was after zip tying the front brake lever about an inch from the throttle for about 18 hours. This idea came from a couple different brake bleed tutorials. After a few ABS bleed cycles, I learned where the motor engages and zip tied just prior to that point. Also, I tried pumping up the brakes, then opening and closing the bleed screw. This seemed to help as I had to add fluid. Tonight the bike is sitting on its center stand and zip tied about an inch from the throttle. I'll do another bleed cycle tomorrow and report back

 

[Slijkmoto]

I was told that the ABS pump needs flushing to get rid of the spongy brakes my 2017 GS also suffers from.
My dealer will perform this at the next service.

 

[Jack Smoke]

I was told that the ABS pump needs flushing to get rid of the spongy brakes my 2017 GS also suffers from.
My dealer will perform this at the next service.

The ABS pump most certainly does need to be ran to properly flush all fluid and bleed If Air Has Been Has Been Introduced. If your just swapping pads and don't open any of the lines, calipers or bleed valves, you shouldn't have to run the pump. Just take the master cylinder cover off and GENTLY rock the caliper back and forth, just enough to get the discs past the pads.

 

[Jack Smoke]

Day 3

Good news, one night on its kickstand and one night on the center stand with the front brake lever zip tied about an inch from the throttle worked!! Also, the method of pumping up the brake pressure, then opening and closing the bleed valve (without moving the brake lever) is a game changer. Brakes feel better than when I bought it. It could use one more bleed, but I'm happy with it and had to go to work today. I may go through and zip tie it tonight and do a quick bleed tomorrow morning to see if it changes anything. I'm at the point I can bleed it in about 10 minutes and the sight glass is just a hair below full, so I shouldn't have to top it off.

Moral of the story, If you have spongy brakes, it is fixable, BMW's aren't " just like that". It takes a computer, proper technique and a lot of patience. If all that doesn't work then check for a mechanical failure.

 

[Nurzo]

If it's spongy brakes after pulling wheel and the pads spread to enable refit of wheel the trick is pump the pads back out very slowly. Or if the brake comes up spongy pull brake lever in and tie it off for an hour or so and then slowly release, this will work most of the time.
What happens is air is added if pumped up quickly and therefore becomes spongy.
The reason tying it off under pressure works is air rises back to the master cylinder under the pressure and out of the system, result a hard brake again.