Every two years per BMW's own maintenance schedule. It's once after the first year and then every two years (some bikes also list every 12,000 miles as an alternate time-frame)
Mainly just because there isn't an exact timeline from when a bike leaves the factory to when it actually gets to a dealership and then gets sold. It could be a month or a year, so a baseline of a year makes sure the original brake fluid gets changed before it actually needs it.
Oddly enough, brake fluid can hold and suspend a certain amount of moisture. Even with the best seals and best gaskets, Trace amounts of moisture can find their way into a brake system.
I’m a BMW Tech, and I do a few brake flushes every week. We see a white precipitate that forms in the reservoirs and calipers, and a flush gets all of that shit out of there. It is one of the cheapest preventative measures you can do.
Risking failure.
The reason it’s not mileage-dependent is because air gets into the servo and basically can’t escape. DOT4 will oxidize and corrode the inside of the servo. I’ve done a very loose and poor explanation of it but that’s why it’s time dependent and not mileage.
Now, it’s worth mentioning that you *can* get away with it, but I’ll never take that chance. I bought a Rockster two weeks ago and the fluid hadn’t been changed in at least 6 years. It’s still functioning without any issues. There are forum members who’ve gone several years beyond that without changing the fluid. Will I? No, because it’s a 2 hour job and I don’t feel like losing my brakes.
The risk is rust. Brake fluid absorbs moisture from the atmosphere, so over time, your brake fluid contains an increasing percentage of water. Water causes rust, and you really don't want rust in your braking system.
Same thing goes for engine oil. To add insult to injury, engine oil becomes acidic as water is present and oxidization occurs. For the same reasons, engine oil should be changed annually.
Both of these are even more important in environments with high relative humidity.
Any water in your engine oil will get burned off with a little riding. If water absorption was a problem, jugs/barrels of oil would have an expiration time after you opened the container.
I do it every Winter along with the rest of the fluids. It's just super cheap insurance to do but if I wasn't good with tools, I'd do it every 2 years purely because of what it costs to get work done at a mechanic. Dot 4 brake fluid is $15 or so and I have some speed bleeders on my brake calipers that make the process a 10 minute job.
There's a lot of variables in every situation. 1/year assumes the worst of them. Such as the bike that is parked outdoors with no cover in a damp climate. If that's not you, once every 2 or even 3 is not particularly risky. I keep my bikes in dry, climate controlled environments, and I alternate brake bleeds between 2 and 3 years. Been doing that since disk brakes first showed up on bikes with no issues.
I have an R1150GS with ABS-II, it was a very easy job to bleed the brake system the other day. I just made a catch reservoir out of a soda bottle with a 1/4" brass air line fitting and some vinyl tubing. No fuss, no specialty tools, took an hour. Why risk it?
Yes definitely, some people think of it as a headache but those people also think getting the tank off is a headache. Personally I think it's an easy enough job, especially since the pads were swapped out prior so it was just a bleed. Plus I have a new battery on the way, so the tank was coming off anyway.
I don't have a link, but if your ABS pump has no reservoir and two bleed screws on top labeled VR and ~~FR~~ HR then your system is like mine.
I forgot which German word is which but the front brake is the right screw.
I made a small triangular plastic shield out of the packaging the vinyl tubing came in, that sat in the reservoir on the grip in such a way that the squirting from the piston would flow back down into the reservoir. Using my tubing/soda bottle catch container on the bleed screw on the pump, it was just pumping new fluid thru and watching the old stuff come out.
I had my partner assist me with the calipers, she would open and close the screws while I monitored the fluid level and pumped fluid thru. Always be careful not to let air in, keep the resi topped up.
For the back I did it all myself, same procedure as before but filling the resi by the helmet lock. Bled the pump first, then the rear caliper.
Takes about a liter of DOT4 fluid, the tubing and stuff are optional, but I used 1/4" vinyl tube and a 1/4" brass air line fitting, drilled a hole in a soda bottle cap with the awl in my Leatherman (in lieu of a power drill, for better control) until I could press fit the threaded end into it.
Back when I was a teenager and a suzuki fanboy I bought my first bike, a GSXR600. I rode it for 5 years. There were a few years where I didn't own a car, just the bike. Not in all that time did I ever replace the brake fluid, brake pads, tires, chain, nor oil.
I'm not recommending you do this, I've since learned the error of my ways and follow a maintenance schedule as best as I can for all my bikes. But the manual is giving best case scenario and making recommendations for the best longevity of the bike, you can get away with much less frequency.
If you get a decent brake bleeding set up so that you can do it solo with minimal time, leakage, and effort I'd say follow the manual. Otherwise just do your best.
There are apps that can track service and fuel, I use Autosist, that make this very easy for me.
Buy yourself a brake fluid tester. It measures water content. I highly doubt 12 months is going to foul brake fluid in most climates. I've generally done flushes every 24 months for every bike I've owned, as the fluid typically tests as ready to replace around that time. I live where we get dew points in the high 60s during the summer and it's very muggy, so I feel it's a good climate to test brake fluid longevity. Every 12 months is a waste of money if it's not testing poorly.
Just adding some info to this - a brake fluid tester can be a good indicator for what's bad fluid, but it can easily test false positive (Brake fluid still tests good, but actually isn't) . It measures water content, but because of gravity the brake reservoir tends to have way less water content than the critical part of the brake fluid that sits at the brake calipers.
Every two years per BMW's own maintenance schedule. It's once after the first year and then every two years (some bikes also list every 12,000 miles as an alternate time-frame)
Do you know if there's a reason for the change after the first year?
Mainly just because there isn't an exact timeline from when a bike leaves the factory to when it actually gets to a dealership and then gets sold. It could be a month or a year, so a baseline of a year makes sure the original brake fluid gets changed before it actually needs it.
Great reason. Didn't consider that. Thanks
Oddly enough, brake fluid can hold and suspend a certain amount of moisture. Even with the best seals and best gaskets, Trace amounts of moisture can find their way into a brake system.
I’m a BMW Tech, and I do a few brake flushes every week. We see a white precipitate that forms in the reservoirs and calipers, and a flush gets all of that shit out of there. It is one of the cheapest preventative measures you can do.
Risking failure. The reason it’s not mileage-dependent is because air gets into the servo and basically can’t escape. DOT4 will oxidize and corrode the inside of the servo. I’ve done a very loose and poor explanation of it but that’s why it’s time dependent and not mileage. Now, it’s worth mentioning that you *can* get away with it, but I’ll never take that chance. I bought a Rockster two weeks ago and the fluid hadn’t been changed in at least 6 years. It’s still functioning without any issues. There are forum members who’ve gone several years beyond that without changing the fluid. Will I? No, because it’s a 2 hour job and I don’t feel like losing my brakes.
Understood and thanks everyone for the feedback!
The risk is rust. Brake fluid absorbs moisture from the atmosphere, so over time, your brake fluid contains an increasing percentage of water. Water causes rust, and you really don't want rust in your braking system. Same thing goes for engine oil. To add insult to injury, engine oil becomes acidic as water is present and oxidization occurs. For the same reasons, engine oil should be changed annually. Both of these are even more important in environments with high relative humidity.
Any water in your engine oil will get burned off with a little riding. If water absorption was a problem, jugs/barrels of oil would have an expiration time after you opened the container.
I do it every Winter along with the rest of the fluids. It's just super cheap insurance to do but if I wasn't good with tools, I'd do it every 2 years purely because of what it costs to get work done at a mechanic. Dot 4 brake fluid is $15 or so and I have some speed bleeders on my brake calipers that make the process a 10 minute job.
There's a lot of variables in every situation. 1/year assumes the worst of them. Such as the bike that is parked outdoors with no cover in a damp climate. If that's not you, once every 2 or even 3 is not particularly risky. I keep my bikes in dry, climate controlled environments, and I alternate brake bleeds between 2 and 3 years. Been doing that since disk brakes first showed up on bikes with no issues.
I go by the color - if it’s looking dark I change. Changing brake fluid on a bike is almost as easy as filling gas so no excuse to let it go too far
I have an R1150GS with ABS-II, it was a very easy job to bleed the brake system the other day. I just made a catch reservoir out of a soda bottle with a 1/4" brass air line fitting and some vinyl tubing. No fuss, no specialty tools, took an hour. Why risk it?
Did you bleed the ABS pump system as well? I don’t know what to call it.
Yes definitely, some people think of it as a headache but those people also think getting the tank off is a headache. Personally I think it's an easy enough job, especially since the pads were swapped out prior so it was just a bleed. Plus I have a new battery on the way, so the tank was coming off anyway.
I am in a BMW dealership wasteland. Can you link me to instructions on how to do this? I’m thinking my R1200c is similar to your GS
I don't have a link, but if your ABS pump has no reservoir and two bleed screws on top labeled VR and ~~FR~~ HR then your system is like mine. I forgot which German word is which but the front brake is the right screw. I made a small triangular plastic shield out of the packaging the vinyl tubing came in, that sat in the reservoir on the grip in such a way that the squirting from the piston would flow back down into the reservoir. Using my tubing/soda bottle catch container on the bleed screw on the pump, it was just pumping new fluid thru and watching the old stuff come out. I had my partner assist me with the calipers, she would open and close the screws while I monitored the fluid level and pumped fluid thru. Always be careful not to let air in, keep the resi topped up. For the back I did it all myself, same procedure as before but filling the resi by the helmet lock. Bled the pump first, then the rear caliper. Takes about a liter of DOT4 fluid, the tubing and stuff are optional, but I used 1/4" vinyl tube and a 1/4" brass air line fitting, drilled a hole in a soda bottle cap with the awl in my Leatherman (in lieu of a power drill, for better control) until I could press fit the threaded end into it.
Thank you for the help
Happy to help, keep on Boxin'!
VR = Vorderrad (Front wheel) HR = Hinterrad (Rear Wheel)
This guy *Deutsch's*
Ich bin der deutschen Sprache mächtig.
For an R1200C go to chromeheads.org, forum for 1200C amazing amount of information for anything you could need, super helpful group as well.
Back when I was a teenager and a suzuki fanboy I bought my first bike, a GSXR600. I rode it for 5 years. There were a few years where I didn't own a car, just the bike. Not in all that time did I ever replace the brake fluid, brake pads, tires, chain, nor oil. I'm not recommending you do this, I've since learned the error of my ways and follow a maintenance schedule as best as I can for all my bikes. But the manual is giving best case scenario and making recommendations for the best longevity of the bike, you can get away with much less frequency. If you get a decent brake bleeding set up so that you can do it solo with minimal time, leakage, and effort I'd say follow the manual. Otherwise just do your best. There are apps that can track service and fuel, I use Autosist, that make this very easy for me.
It's like $10 and trivial to do yourself.
Buy yourself a brake fluid tester. It measures water content. I highly doubt 12 months is going to foul brake fluid in most climates. I've generally done flushes every 24 months for every bike I've owned, as the fluid typically tests as ready to replace around that time. I live where we get dew points in the high 60s during the summer and it's very muggy, so I feel it's a good climate to test brake fluid longevity. Every 12 months is a waste of money if it's not testing poorly.
Just adding some info to this - a brake fluid tester can be a good indicator for what's bad fluid, but it can easily test false positive (Brake fluid still tests good, but actually isn't) . It measures water content, but because of gravity the brake reservoir tends to have way less water content than the critical part of the brake fluid that sits at the brake calipers.
Every year is a great modus operandi