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Thread: Rear brake fluid reservoir cap question

  1. #16
    Registered User ezwicky's Avatar
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    Quote Originally Posted by 20774 View Post
    Should work with a file that small. I assume they are JPGs. You hang out of various forums, so this shouldn't be that difficult. It's really easy, though, so I'm scratching me head.

    You are trying to upload from your computer? Not sure how that would work on a smartphone...
    From my laptop. I do this all the time. Not here though. But I get the expected popups and dialog boxes, but nothing happens after I select a single file and "upload". Nothing. I'll reboot and try again.
    BMWMOA #182796

    '76 R90/6
    '80 R100RS restoration project

  2. #17
    Liaison 20774's Avatar
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    Well, you certainly know how to do it...you did it back in 2013!

    https://forums.bmwmoa.org/showthread...l=1#post874844
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #18
    Registered User ezwicky's Avatar
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    Seems to be working using FireFox.

    Not work with Chrome.

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    'scuse my feet!
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    BMWMOA #182796

    '76 R90/6
    '80 R100RS restoration project

  4. #19
    Registered User ezwicky's Avatar
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    Here's that bike now

    Quote Originally Posted by 20774 View Post
    Well, you certainly know how to do it...you did it back in 2013!

    https://forums.bmwmoa.org/showthread...l=1#post874844
    IMG_1581.jpg
    IMG_1582.jpg
    BMWMOA #182796

    '76 R90/6
    '80 R100RS restoration project

  5. #20
    Registered User STEVENRANKIN's Avatar
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    Micro fiche and things

    So, my quick look at a BMW microfiche shows no part number for the cap and float separate. The whole unit is #18, Cap and reservoir. Kind of looks like there never was a way to buy the individual internal parts such as the float. Further, the part 149 has been superseded and is NLA. The new part 961 does not show the float and likely it is to be used in the 81 and newer bikes. In 81, BMW removed the front brake master cylinder front under the gas tank placing it on the handle bar. At the same time, they removed as far as I know the brake level electrical system because any instrument cluster I have seen since then does not have a brake level warning light. The Brake level warning light was removed and the High beam light was moved from the tach to the center.

    Seems you found the reason for the float sticking and I hope you can fix it, I guess the only thing other than that is to look for a used one. Hope this makes sense. St.

  6. #21
    Registered User AntonLargiader's Avatar
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    The under-tank MC had the float system because the brake fluid level was not able to be checked with a normal visual inspection. When the MC went to the handlebar you could see the level and no longer needed the light. I'm not sure why the rear ever had a float; maybe just because BMW already had the warning system in place and couldn't resist the chance to extend its use. But if you can see the fluid level, you don't need the float.
    Anton Largiader 72724
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  7. #22
    Registered User ezwicky's Avatar
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    Thanks Anton, that makes sense. I'll just use it as-is, since it's sound in every other way.
    BMWMOA #182796

    '76 R90/6
    '80 R100RS restoration project

  8. #23
    Registered User STEVENRANKIN's Avatar
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    Who knows

    Anton, we will never know why BMW did things they did. My 78 RS has a rear master cylinder with the float and wiring tied into the warning light on the dash. Either the front or the rear low level will light the light.

    It was a short span of years they used a hydraulic rear brake with the float and switch. The early 77 RS bikes had drum rear brakes as did the /7 bikes, Then in 78 the RS went to disc, followed in 79 by the new RT. As for the 78 and newer /7 bikes and the S bikes it is fuzzy on when or if discs were used or drum. Oh, the S bikes used disc, not sure if drum was used all years of the /7 bikes.

    All I know is 80 and 81 was the cross over for changes in the bikes for brakes and ignition systems. Kurt and Snowbum, LOL keep better track of things than I do. St.

  9. #24
    Registered User lkchris's Avatar
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    Quote Originally Posted by STEVENRANKIN View Post
    Anton, we will never know why BMW did things they did. My 78 RS has a rear master cylinder with the float and wiring tied into the warning light on the dash. Either the front or the rear low level will light the light.

    It was a short span of years they used a hydraulic rear brake with the float and switch. The early 77 RS bikes had drum rear brakes as did the /7 bikes, Then in 78 the RS went to disc, followed in 79 by the new RT. As for the 78 and newer /7 bikes and the S bikes it is fuzzy on when or if discs were used or drum. Oh, the S bikes used disc, not sure if drum was used all years of the /7 bikes.

    All I know is 80 and 81 was the cross over for changes in the bikes for brakes and ignition systems. Kurt and Snowbum, LOL keep better track of things than I do. St.
    BMW was unique in having an under tank brake fluid reservoir and since you couldn't readily see the fluid level, they provided a fluid level warning capability. When they went to the handlebar reservoir, the fluid level was easily visible and no level warning was necessary. The rear level warning never was necessary, but the circuitry was there so they did it.

    BMW is massively safety conscious and since it is essentially a family owned company they are extra conservative regarding their liability. Motorcycles are "dangerous!"
    Kent Christensen
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