Brake Fluid Change - How To Get the Cap Off - BMW F800 Riders Forum & Registry



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  1. #1
    Daboo's Avatar
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    My brake fluid in the front reservoir just turned milky. I've never seen that before. So I got to looking at how to change the brake fluid.

    The first obstacle I came across was in removing the cap. How do you get that cap off?

    Chris
    Elnathan - 2014 BMW F800GT
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    Do you have the bobble head reservoir like I do on my F650GS? That requires a cheap metal BMW tool to remove the cap. They keep the cap from unscrewing. Look closely at the area directly under the cap to see the two thin pieces that need to be squeezed inward while turning the cap.
    Richard - Current bikes: 2016 BMW R1200RS, 2018 16.6 kWh Zero S, 2011 Royal Enfield Bullet 500 Classic, 2009 BMW F650GS, 2005 Triumph T-100 Bonneville, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior. 

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    Okay, I figured it out. But in the interests of the next poor BMW owner trying to do this, here's the "tool" you need.



    Click image for larger version. 

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    The "tool" is a shoe string. There are two tangs that need to be depressed to allow the cap to turn. The shoe string pulls the tangs out of the way and the cap turns easily.

    The brake fluid changed dramatically. It's a creamy color now. Before it was more like a black coffee color. When I pulled the cap off, you can clearly see the condensation under the cap.

    Chris
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    Elnathan - 2014 BMW F800GT
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    notacop is offline The original Schwartz Wald Troll
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    It's like a child proof cap on medicine. It's BMW's customer proof cap! For $100 or so the dealer did my ST fluid change but that was ages ago, probably $200 happy day dollars now!

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    Quote Originally Posted by Richard230 View Post
    Do you have the bobble head reservoir like I do on my F650GS? That requires a cheap metal BMW tool to remove the cap. They keep the cap from unscrewing. Look closely at the area directly under the cap to see the two thin pieces that need to be squeezed inward while turning the cap.
    Thanks, Richard. I saw one of your earlier posts where you had bought the tool. It didn't seem too pricey either. Then I came across this "tool".

    Chris
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    Just a quick follow-up. Here's what the inside of the cap looked like and the brake fluid. I have no idea how the moisture got in like that.

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    Elnathan - 2014 BMW F800GT
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    How many years since the fluid was last changed?

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    Probably since 2014 when the original owner bought it.

    I kinda go by the theory that our motorcycles ought to be able to survive the way our cars do. How many people ever check their car's valves? And I'm thinking back 20 years when cars had that on the maintenance schedule. To be honest, I change the antifreeze and brake fluid in my cars when something fails and it has to be done. And I don't have a problem. Most of the cars I have owned, I've kept for 15-18 years.

    So to have this happen, was totally unexpected. I knew that dark brake fluid meant I should change it. But I also knew what I felt in normal riding. The brakes work great.

    But this? This was like picking up a carton of milk and suddenly finding the milk was spoiled and curdled. OMG!

    I have what I need to bleed the brakes tomorrow. It's not hard. And I guess I found the incentive to do it and not wait like I do my cars. D:

    Chris
    Elnathan - 2014 BMW F800GT
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    Quote Originally Posted by Daboo View Post
    Okay, I figured it out. But in the interests of the next poor BMW owner trying to do this, here's the "tool" you need.



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    The "tool" is a shoe string. There are two tangs that need to be depressed to allow the cap to turn. The shoe string pulls the tangs out of the way and the cap turns easily.

    The brake fluid changed dramatically. It's a creamy color now. Before it was more like a black coffee color. When I pulled the cap off, you can clearly see the condensation under the cap.

    Chris
    Very creative and informative. I was also planning to change my brake fluid and pads soon (I've already procured replacement pads and a bleeding tool). I would have been stuck at the cap opening stage as well if I have not come across this post. Thanks!

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  19. #10
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    Quote Originally Posted by Daboo View Post
    ...
    I change the antifreeze and brake fluid in my cars when something fails...
    I struggle to understand why the neglect.

    It's cheap, simple and not time consuming task to maintain your brakes.


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    BMW and most other motorcycle manufacturers recommend that brake fluid be changed every two years. However, I find it interesting that on my R1200RS (and other new BMW models) neither the clutch fluid nor the coolant have specified replacement intervals. I recently had my R-bike serviced at SF BMW and was told that the coolant used was the same as that used in BMW cars, was good for the life of the vehicle and would never need to be replaced unless coolant system needed mechanical repairs. That was certainly news to me, as I have always changed my coolant at 2 year intervals. The clutch fluid is a different type of fluid than that used in the brake system and does not absorb moisture from the air (or so they say) which is why it doesn't need to be replaced.
    Richard - Current bikes: 2016 BMW R1200RS, 2018 16.6 kWh Zero S, 2011 Royal Enfield Bullet 500 Classic, 2009 BMW F650GS, 2005 Triumph T-100 Bonneville, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior. 

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    Quote Originally Posted by BoxerBits View Post
    I struggle to understand why the neglect.

    It's cheap, simple and not time consuming task to maintain your brakes.


    Sent from my moto g(6) play using Tapatalk
    My understanding is that with ABS equipped bikes it's not that straight forward as the ECU or Can bus or whatever has to open and shut valves in the ABS modules during the flushing and bleeding process to fully clear the fluid out of the system. Do I have that wrong?
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  24. #13
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    Quote Originally Posted by MGD109 View Post
    My understanding is that with ABS equipped bikes it's not that straight forward as the ECU or Can bus or whatever has to open and shut valves in the ABS modules during the flushing and bleeding process to fully clear the fluid out of the system. Do I have that wrong?
    On the Servo Assisted R1150 that is the case but even then, it's not a reason for not changing the fluid.

    Bikes with no Servo assistance such as the R1100 and F800, can be bled using traditional methods.

    It's a safety issue, although from experience, I'm pretty certain others will disagree.

    Ride safely.








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  25. #14
    notacop is offline The original Schwartz Wald Troll
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    MGD, Norm Kajikawa and I did the brakes on our ST's with the help of his 911 and lap top. A command makes the ABS pulse while holding the brake lever. I didn't find any difference in the feel of the lever after the cycle took place. We did that a few times for good measure. Unless the ABS has a secret compartment that has ABS use fluid reserved, what goes in at the lever reservoir is what goes out at the brake caliper.
    The dealer charged $100 when I had them do it. Norma and I spent a few bucks on fluid. He did have a 911 and his laptop but those are purchases that serve for many uses besides a fluid change so the cost of those will be amortized over a period of time and not specific to the task at hand.
    I'm with Daboo on car maint. Cars go many years and don't have the maint schedules followed as many do for motorcycles That neglect of car service has a cost though. I'm about to pay a shop $3200 for the 20 year service on my 4Runner. Dang the bad luck for not doing it myself.

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    Quote Originally Posted by notacop View Post
    MGD, Norm Kajikawa and I did the brakes on our ST's with the help of his 911 and lap top. A command makes the ABS pulse while holding the brake lever. I didn't find any difference in the feel of the lever after the cycle took place. We did that a few times for good measure. Unless the ABS has a secret compartment that has ABS use fluid reserved, what goes in at the lever reservoir is what goes out at the brake caliper.
    The dealer charged $100 when I had them do it. Norma and I spent a few bucks on fluid. He did have a 911 and his laptop but those are purchases that serve for many uses besides a fluid change so the cost of those will be amortized over a period of time and not specific to the task at hand.
    I'm with Daboo on car maint. Cars go many years and don't have the maint schedules followed as many do for motorcycles That neglect of car service has a cost though. I'm about to pay a shop $3200 for the 20 year service on my 4Runner. Dang the bad luck for not doing it myself.
    On cars I've seen the ABS bleed make a huge difference. Big enough to change the entire feel of the brake pedal and to clear the ABS light on the dash. Per maintenance schedule: it just depends on your vehicle, environment, use, comfort level of the driver/rider to unexpected conditions, and expected cost of future repairs. For instance, on my European cars I am religious about changing brake fluid because calipers can cost over $500 a piece and I'm not chancing rusting up the system. On a Toyota? Who cares if your caliper seizes, junkyard has them for almost nothing. Also, a single caliper seizing on a car isn't a huge deal for me, car will brake fine if not a bit unevenly. I can see being more religious with fluid change intervals and inspecting components for a motorcycle, loosing a wheel or seizing up the engine means a totally different thing on a motorcycle than on an car..

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    When I bought my GS the records indicated that the fluid had never been changed (36k miles), it didn't look bad, but it was darker than I'd like. I flushed until it was clear, then cycled the ABS with my GS-911. When flushing again after cycling the pump, I got enough more contaminated fluid out to make me feel good about going that extra step. I know it will eventually dilute back into the system, but the same cost argument applies here. If the pump were to fail it's a very costly replacement and has to be 'paired' back into the bike by a dealer with the dealers software tools, and they won't do that unless you buy it new from them ($$$$).

  28. #17
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    Quote Originally Posted by BoxerBits View Post
    I struggle to understand why the neglect.

    It's cheap, simple and not time consuming task to maintain your brakes.


    We bought a 1999 Toyota Camry new. We kept it till 2016. About all I did to it was to change the oil and oil filter. The air filter never needed cleaning. Maybe something about the mud here in Seattle not dirtying up the air filters like blowing sand does in Texas? Tires were changed, obviously. But brakes? I think we did brake changes only a few times in all those years. I don't remember the coolant ever being changed. We kept that car for 17 years and well over 200,000 miles. It ran like a clock when we finally sold it and bought...another Toyota.

    When I was riding through South Dakota, I pulled into a McDonald's for lunch. A R1200GS rider pulled in at the same time. He was in the middle of a long trip, like I was. But he was totally absolutely consumed with finding a BMW dealer to change the oil in his GS because it was due and he couldn't ride any further till it was changed...by a BMW technician. I told myself I'm glad I don't have a GS. I'd hate to have a motorcycle that was that fragile.

    My father taught me, that if it wasn't broke, don't fix it. I'll do preventative maintenance, but in some cases, I'll just watch the situation carefully. The brake fluid color changed fairly soon after buying the bike...and then stayed like that. Braking has remained superb. But once it changed yesterday, there was no question about going any further without changing it.


    Chris
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  30. #18
    notacop is offline The original Schwartz Wald Troll
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    "He was in the middle of a long trip"
    Oil change interval now is 6K and filters at 12K on many bikes. If one is doing constant touring miles that interval can probably be extended. It's the heat cycle and low rpm around town that can wear the oil, from what I'm been given to understand. Or if your bike burns a quart every thousand miles, keep putting new in and don't worry about it. My 80/7 used to burn a quart from LA to Norman, OK. On Air Heads aftermarket oil pans increased the capacity from 2 quarts to 3. Always nice to have a larger oil capacity.

  31. #19
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    Guess I'll always struggle to understand the rationale of "wait untill it breaks" when it comes to break system maintenance.

    Ride safely.




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  33. #20
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    I change the brake fluid every two years. It has been my understanding that with brake fluid being hygroscopic (absorbs moisture) that moisture can damage brake parts over time. Pay me now or pay me later. Like anything, I am sure others roll the dice and have no problems.

    I have a friend who rides his bike very little so he accumulated low mileage over the course of a year. He would change his oil every 3 years (I used to joke whether it needed it or not!) and store the bike in his outside shed. I cautioned against that practice and said you still should change the oil every 12-18 months - even if only riding 1K miles or less a year. He saw that as a waste of money. Last summer he needed a new clutch on a very low mileage bike. I have ridden with him and he is experienced and does not abuse the clutch. First thing the shop asked after taking the clutch apart was,'how often do you change the oil?".
    2009 F800ST (Night Blue Metallic) l 1999 SV650 (Naked & Red) l 2016 GSX S1000 (Naked & Blue)
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  35. #21
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    Okay...I'll change the brake fluid more often.

    I would say you convinced me, but just looking at that brake fluid did that.

    Chris
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    When I change fluid......the first thing I do is take a Turkey Baster and suck the old fluid out of the reservoir. This allows you to put fresh fluid in the reservoir when you begin the process of getting the old fluid out. There is no need to run that crappy stuff in the reservoir through the system - just to spend more time trying to flush it out. It is likely the fluid down inside is not as nasty as the stuff in the reservoir.

  38. #23
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    Agreed. I sucked out 97% of it yesterday. I want to get the remaining amount out of the reservoir also.

    Chris
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    Quote Originally Posted by MGD109 View Post
    My understanding is that with ABS equipped bikes it's not that straight forward as the ECU or Can bus or whatever has to open and shut valves in the ABS modules during the flushing and bleeding process to fully clear the fluid out of the system. Do I have that wrong?
    When conditions trigger the ABS system (i.e your motorcycle is moving forward but your tire is not rotating. More accurately described as the rotation of one tire being out of range to the rotation of the other tire.) ABS uses small valves to CLOSE the path of fluid to the calipers. Closing the path removes the pressure you are delivering to the calipers when pressing a lever.

    No pressure to the calipers = no braking = tire rotation = control. Of course, all this happens in tenths of a second.

    So, the default on to the ABS module is OPEN. Otherwise you'd lose all ability to brake if the ABS module failed.

    This means no deviation from normal brake fluid flushing procedures. Systems that include a brake assist feature will be different but that's not about the ABS.
    Concrete remains undefeated. 

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    Quote Originally Posted by Daboo View Post
    Okay...I'll change the brake fluid more often.

    I would say you convinced me, but just looking at that brake fluid did that.

    Chris
    You live in a humid area and the brake fluid is exposed to moisture in the air through the reservoir cap. It has to vent to atmosphere (to prevent a vacuum) and allow the brake fluid to flow to the calipers as the brakes are applied...and as the pads wear down.

    One problem with moisture in the fluid is the corrosion and pitting of the aluminum parts that then can cause a leak where the seals meet it, or in one case I had, a BLOCKAGE of port for the return of fluid back to the reservoir, causing the rear brake to drag as the day got hotter.
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    Quote Originally Posted by columbo View Post
    You live in a humid area and the brake fluid is exposed to moisture in the air through the reservoir cap. It has to vent to atmosphere (to prevent a vacuum) and allow the brake fluid to flow to the calipers as the brakes are applied...and as the pads wear down.

    One problem with moisture in the fluid is the corrosion and pitting of the aluminum parts that then can cause a leak where the seals meet it, or in one case I had, a BLOCKAGE of port for the return of fluid back to the reservoir, causing the rear brake to drag as the day got hotter.
    Every reservoir I have ever seen has a bellows that seals the fluid from contact with the air while being able to accordion to ensure that no vacuum is produced.

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  43. #27
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    There's one inside the reservoir, just like you said.

    I had about 5 opened containers of brake fluid in the garage. They are probably 10 years old. Interestingly, all of them look fresh. I would've thought that by now, they would show signs of contamination.

    Chris
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    Congratulations defeating the adult proof cap!
    Simple and ingenious.
    Concrete remains undefeated. 

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    Quote Originally Posted by Daboo View Post
    There's one inside the reservoir, just like you said.

    I had about 5 opened containers of brake fluid in the garage. They are probably 10 years old. Interestingly, all of them look fresh. I would've thought that by now, they would show signs of contamination.

    Chris
    If you really want to test 10 year old DOT 4 try the following or similar :-

    https://www.lasertools.co.uk/product/4875

    Personally, and like most I'd imagine, I'd just buy a small bottle of fresh stuff from a factors for very little money. I'd be safe, and know that I'm not pouring a further problem into my brake system. But then again each to his/her own degree not excitement.

    Stop safely.


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  47. #30
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    If you have a 3D printer you can print a replica of the BMW tool.

    Click image for larger version. 

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  48. #31
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    Quote Originally Posted by bmwroadsterca View Post
    Every reservoir I have ever seen has a bellows that seals the fluid from contact with the air while being able to accordion to ensure that no vacuum is produced.

    Sent from my SM-T813 using Tapatalk
    I've seen them too.

    Someone, please explain where, when and how moisture manages to get into our hydraulic systems on what is usually thought of as "sealed."

    Hydraulic brakes have been around for 100 years, and we still have a chronic problem with moisture build-up and hygroscopic fluid, hence the scheduled "preventive maintenance" very 2 years.
    2013 BMW F800GT, 2013 Triumph Bonneville, 2017 Honda CTX700D DCT 

  49. #32
    Daboo's Avatar
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    Quote Originally Posted by BoxerBits View Post
    If you really want to test 10 year old DOT 4 try the following or similar :-

    https://www.lasertools.co.uk/product/4875

    Personally, and like most I'd imagine, I'd just buy a small bottle of fresh stuff from a factors for very little money. I'd be safe, and know that I'm not pouring a further problem into my brake system. But then again each to his/her own degree not excitement...
    Interesting tool. But at that price, it is cheaper to just buy new DOT 4 brake fluid...which I have already.

    Quote Originally Posted by columbo View Post
    ...Someone, please explain where, when and how moisture manages to get into our hydraulic systems on what is usually thought of as "sealed."

    Hydraulic brakes have been around for 100 years, and we still have a chronic problem with moisture build-up and hygroscopic fluid. hence the scheduled "preventive maintenance" very 2 years.
    I'd be interested to know the answer to this too. Yes, I live in a rainy climate. But our humidity is probably less than that of people living in the southeast of the USA. I've obviously never had the cap off...because I had no idea how to get it off. There are no leaks in the system. So...how does the moisture get in?

    And if moisture was going to get in and turn the brake fluid that color...why is the 10 year old brake fluid in the opened containers, not contaminated? It makes no sense to me.

    Chris
    Elnathan - 2014 BMW F800GT
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  50. #33
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    Quote Originally Posted by Daboo View Post

    ...
    And if moisture was going to get in and turn the brake fluid that color...why is the 10 year old brake fluid in the opened containers, not contaminated? It makes no sense to me...
    Really glad that you've changed that fluid with fresh stuff.

    For your question. There is at least one other person on this thread who appears to understand why. I'd suggest that you talk to a local competent, patient, time served mechanic who should be able to explain to you the cause.

    Ride safely Chris.

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  51. #34
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    The reason that I change my brake fluid every two years is because brake fluid is a lot cheaper than the cost of replacing a corroded sticking brake caliper with a new one.
    Richard - Current bikes: 2016 BMW R1200RS, 2018 16.6 kWh Zero S, 2011 Royal Enfield Bullet 500 Classic, 2009 BMW F650GS, 2005 Triumph T-100 Bonneville, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior. 

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  53. #35
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    I found it interesting in that the fluid coming out of the bleeder screw, looked fresh. I thought it would've been dark at least.

    Chris
    Elnathan - 2014 BMW F800GT
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  54. #36
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    It's fun reading these threads. I love spellcheck that helps us say what we don't mean.

    "Guess I'll always struggle to understand the rationale of "wait untill it breaks" when it comes to break system maintenance." Haha that is break system maintenance for sure.

    On a more serious not I just got my bike back from the 24,000 mile service. They did change the brake fluid along with the drive belt, tensioner, spark plugs and air cleaner along with checking valve clearances. I'm about to post the valve clearance to that thread - all were OK except for one intake at 0.2 instead of between 0.27 and 0.33.

  55. #37
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    Did you keep the old belt for a spare? Mine is still the original at 50,000 miles.

    It hasn't braked yet.

    Chris
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    IBA# 49894 True Rounder = 0-20's - Rounder -- to -- 100's+ Red Hot Rounder

    John 14:6 

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  57. #38
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    Seeing you get 1/3 the rain we riders in Ketchikan get, I'd still suspect ambient moisture in the air, gotta change it on schedule.

  58. #39
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    Some interesting questions in this thread. As I understand it, Glycol based brake fluid is hydroscopic and will, over time absorb moisture from the air through microscopic pores in the hydraulic lines and seals. Hence the need to change at regular intervals. I don't know if the colour change is related to how much moisture has been absorbed. I do know that the brake fluid in the rear reservoir of my ST and both my GT's went brown after a year due to some kind of dye in the rubber hoses leaching into the fluid. After changing the fluid on those bikes, it always stayed a nice yellow colour between fluid changes. I think that silicon brake fluid is hydrophobic, which means it doesn't absorb moisture and has been used on US military vehicles since the early 90's for that reason.

  59. #40
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    Yes lots of questions but the craic is, change it to a schedule to avoid anything like this :-

    https://www.theguardian.com/world/20...-inquest-hears

    Root cause of above was found to be down to poor maintenance of braking system. Some eejit thought they new better to save time/money with vehicle maintenance I guess.

    Ride safely.

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  60. #41
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    It's $5.00 for a bottle of brake fluid.
    I can think of other places I'd rather save that kind of money.

    It's the cheapest insurance against wear and failure that you'll find.
    Concrete remains undefeated. 

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  62. #42
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    Beautiful! Now I know what to do when it's my turn.

  63. #43
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    I got rid of the "specimen cup" brake fluid tank on my 800ST. I purchased a Rizoma CNC brake fluid tank. Easy install. The top just unscrews, and it looks great:

    https://www.revzilla.com/motorcycle/...rake-reservoir

  64. #44
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    Quote Originally Posted by columbo View Post
    I've seen them too.

    Someone, please explain where, when and how moisture manages to get into our hydraulic systems on what is usually thought of as "sealed."

    Hydraulic brakes have been around for 100 years, and we still have a chronic problem with moisture build-up and hygroscopic fluid, hence the scheduled "preventive maintenance" very 2 years.
    Moisture is absorbed through the rubber parts of the system over time. Water molecules are pretty small. Rubber molecules are big and have gaps.

    There are two problems with not changing the fluid at the proper interval. The first is that the moisture causes corrosion. The second is that if you are braking hard (mountains, racing), and there's moisture in between the brake fluid molecules, it turns to steam at only 100°C and you lose your brakes when you need them the most. Some systems have more rubber parts than others.

    -former brake test tech

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  66. #45
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    Quote Originally Posted by danexmachina View Post
    Moisture is absorbed through the rubber parts of the system over time. Water molecules are pretty small. Rubber molecules are big and have gaps.

    There are two problems with not changing the fluid at the proper interval. The first is that the moisture causes corrosion. The second is that if you are braking hard (mountains, racing), and there's moisture in between the brake fluid molecules, it turns to steam at only 100°C and you lose your brakes when you need them the most. Some systems have more rubber parts than others.

    -former brake test tech
    Oh..and the rubber absorbs some of the brake fluid, so that hygroscopic nature of the brake fluid becomes a 'feature' of old rubber brake parts. Eventually, it's like your brake fluid is directly exposed to the air because the brake fluid molecules absorbed in the old rubber provide a path to pick up water molecules from the air and bring them inside. Kinda like how a cell digests food. Eventually, you have to replace the rubber parts, but newer synthetic rubbers are getting better than old ones, to a point, and newer fluid technologies are a little better.
    Harley used silicone brake fluid (mostly to protect paint on the assembly lines), and it doesn't absorb moisture. It absorbs air instead. Just a different problem (squishy feel).
    It also requires different rubber chemistry, so don't mix them up.

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  68. #46
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    Quote Originally Posted by Runmyownlife View Post
    It's $5.00 for a bottle of brake fluid.
    I can think of other places I'd rather save that kind of money.
    It's cheaper than Scotch.

    Rich, before thinking that DOT 5 brake fluid is worth buying for your GT, check out some articles and videos on the differences between the DOT brake fluids. I don't remember what the warning was all about, but it was enough that I didn't think twice about sticking with DOT 4.

    It was an easy job. The front brakes were a bit awkward to do by myself, so I asked my wife to come out and squeeze the brake levers for me. It took very little time.

    I decided to buy the Harbor Freight brake bleeder. Waste of money, except I was able to take it back with no questions asked. Just like the online videos, I couldn't get more than 7 psi of vacuum.


    Chris
    Elnathan - 2014 BMW F800GT
    IBA# 49894 True Rounder = 0-20's - Rounder -- to -- 100's+ Red Hot Rounder

    John 14:6 

  69. #47
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    Don't buy DOT 5 fluid. It is incomparable with our braking systems. You want DOT 4, DOT 5.1 or DOT 6.1. But DOT 4 works just fine and is a lot cheaper than the other brake fluids that have higher boiling points, which you don't need.
    Richard - Current bikes: 2016 BMW R1200RS, 2018 16.6 kWh Zero S, 2011 Royal Enfield Bullet 500 Classic, 2009 BMW F650GS, 2005 Triumph T-100 Bonneville, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior. 

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