BMW K bikes (Bricks)

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Dai

Dai
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My rear brakeswitch gave up the ghost and I quickly discovered that it wasn't going to come out of the mounting bracket because it was corroded solid in there. What appears to be a solid hex is a metal stamping and it collapses quite easily. As I was making a set of braided lines to fit LFB anyway, my solution was to fit a hydraulic switch instead.

Another possible solution to the corroded brakeswitch problem Bb2

The wires obviously aren't going to reach the sidepanel, so I extended them with 16/0.2 thinwall by soldering the ends together and sheathing with heatshrink. I then covered the lot with PVC sleeving. At the other end I cut off the existing plug and crimped on female Japanese connectors.

Another possible solution to the corroded brakeswitch problem Bb3

The only change on the brake line from standard at the caliper end was to use a banjo bolt.

Another possible solution to the corroded brakeswitch problem Bb1

I bought a batch of hydraulic switches from China via ebay: £15.00 for six switches as opposed to £11.50 for one switch here. They're exactly the same item.

    

92KK 84WW Olaf

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Thanks for the warning. My rear brake switch is kaput too and not done because the old one doesn't want to come out. I haven't applied brute force as that never seems to work on these things. Space to get at it is tight.

Your rear brake fluid reservoir seems to have an interesting mounting.....stainless steel?


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

RicK G

RicK G
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I have never been keen on pressure operated brake switches because you can't just tap the lever to bring the light on for a moment without working the brake.


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"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

Dai

Dai
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92KK K100LT 193214 wrote:
Your rear brake fluid reservoir seems to have an interesting mounting.....stainless steel?

Yes - this is actually MkII because as you can see, I had to replace the hydraulic reservoir too - a friend made this one for me many years ago but for a different bike. I'm sure Fritz had just returned from Oktoberfest when he designed the original bracket - having to remove the battery just to remove the footrest hanger? MkI was a simple right-angle that held the BMW reservoir and slid down behind the footrest hanger in place of the standard penny washer.

@RicK G wrote:I have never been keen on pressure operated brake switches because you can't just tap the lever to bring the light on for a moment without working the brake.

There is that. It's a tradeoff between long term reliability and being able to tell the guy behind you to back off.

    

KJustin

KJustin
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Sorry to ressurect an old thread.  Would a hydraulic switch work on the front brake in place of the manual switch? 

I ask because the front brake switch works by releasing the switch button (and I don't know what's actually going on inside that switch).  I don't know if that's differnet than the mechanism by which a hydraulic switch works (or if it even matters). 

BTW, I put a hydraulic switch on my rear brake and it works great.  But I did it long enough ago that I don't recall how the OEM switch worked (if I ever knew) and whether it differs from the front.


__________________________________________________
1985 K100 Cafe Racer (formerly an RT), VIN 0051736
    

92KK 84WW Olaf

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KJustin,

Depends on which K100 you have. Mine is 84 and the front and rear brake switch and also the clutch lever brake switch are the same parts! When you pull the lever the little plastic plunger [should] come out and [should] complete a circuit inside the switch to illuminate the brake light, or allow the starter to operate.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

KJustin

KJustin
Silver member
Silver member
Olaf, thank you.  What you describe is what I have on my 85 K100RT (now cafe'd) and perfectly answers the queston.  Therefore, a hydraulic switch should work fine on the front brake. It will be a few weeks until I make this mod as I'm in the middle of some other things right now.  I'll report back to the forum if there's any problem.  If you don't hear from me, all future readers of this thread can assume it worked fine.


__________________________________________________
1985 K100 Cafe Racer (formerly an RT), VIN 0051736
    

Dai

Dai
Life time member
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It will be fine - I have hydraulic switches on LFB, so you have nothing to worry about.


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'83 K100 upgraded to K100RS spec, '87 K100RT
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'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California
    

92KK 84WW Olaf

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@KJustin wrote:Olaf, thank you.  What you describe is what I have on my 85 K100RT (now cafe'd) and perfectly answers the queston.  Therefore, a hydraulic switch should work fine on the front brake. It will be a few weeks until I make this mod as I'm in the middle of some other things right now.  I'll report back to the forum if there's any problem.  If you don't hear from me, all future readers of this thread can assume it worked fine.

Thanks for that. What you describe will work but I also subscribe to being able to flash the brakes without using them. The hydraulic switch only works AFTER you have started to pressurise the brake circuit. The switch works by exposing the pin within the range of the free play at the lever, ie before you pressurise the brakes. I ride the K all year including frost and its quite useful when you are braking very very slowly to have a brake light on. The other thing is and its pedantic is that the three switches being same you can swap them around quite easily if you do get a failure. However you can always develop the habit of tapping one or other brake first if one of them has a switch but my preference particularly on the rear is to have the ability to flash or use a brake light. Enough of having following vehicles a little too close for comfort!

Funny thing too any car I have had has a switch and not a pressure sensor, located at the foot brake pedal.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

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