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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: injected59 on May 30, 2024, 11:13:38 AM

Title: 1994 K75 Rear brakes ABS? Reservoir?
Post by: injected59 on May 30, 2024, 11:13:38 AM
Hey everyone, recently picked up a '94 K75.  Looks like a prior owner diddled with the rear brakes to get them functioning for sale.  From what I've read this bike should have ABS correct?  All that seems to be missing.  Also, I assume the reservoir is aftermarket.  Where is it normally mounted (currently zip tied).
Thanks Chris
Title: Re: 1994 K75 Rear brakes ABS? Reservoir?
Post by: Lbxpdx on May 30, 2024, 11:55:03 AM
Some folks decide to pull the ABS system, as the brain can ECU can be a bit expensive to replace. 
Title: Re: 1994 K75 Rear brakes ABS? Reservoir?
Post by: Laitch on May 30, 2024, 12:09:20 PM
ABS was an option on the RT. Your Brick possibly didn't have it.


Your Brick not only has an aftermarket brake fluid reservoir but also an aftermarket rear brake master cylinder. It's probably from a Chinese manufacturer and is a common modification around here when the OEM Magura master cylinder fails from corrosion through lack of maintenance. The tip-off is your master cylinder's supply hose input is at the bottom of the cylinder.

The original reservoir (photo from Euro Motoelectric) is mounted into a horseshoe-shaped spring steel clip (photo from MaxBMW parts fiche) adjacent to a frame member that is concealed by the removable brake-side battery cover, or partially concealed by a low-seat panel like your Brick has.

(https://www.motobrick.com/gallery/4/1601-300524120224.png)

(https://www.motobrick.com/gallery/4/1601-300524120640.png)
Title: Re: 1994 K75 Rear brakes ABS? Reservoir?
Post by: Laitch on May 30, 2024, 01:16:11 PM
(https://www.motobrick.com/gallery/4/1601-300524131340.jpeg)


(https://www.motobrick.com/gallery/4/1601-300524131429.jpeg)
Title: Re: 1994 K75 Rear brakes ABS? Reservoir?
Post by: injected59 on May 30, 2024, 01:27:30 PM
ABS was an option on the RT. Your Brick possibly didn't have it.


Your Brick not only has an aftermarket brake fluid reservoir but also an aftermarket rear brake master cylinder. It's probably from a Chinese manufacturer and is a common modification around here when the OEM Magura master cylinder fails from corrosion through lack of maintenance. The tip-off is your master cylinder's supply hose input is at the bottom of the cylinder.

The original reservoir (photo from Euro Motoelectric) is mounted into a horseshoe-shaped spring steel clip (photo from MaxBMW parts fiche) mounted on a frame member that is concealed by the removable brake-side battery cover.

(https://www.motobrick.com/gallery/4/1601-300524120224.png)

(https://www.motobrick.com/gallery/4/1601-300524120640.png)

Laitch, thank you for the info.  I guess if it were the front brakes I'd be concerned.  It seems to be functioning OK, so I guess I will leave it be for now, aside from getting rid of the zip tie and permanent mount the reservoir. 
Title: Re: 1994 K75 Rear brakes ABS? Reservoir?
Post by: frankenduck on May 30, 2024, 02:18:36 PM
If that's the original peg plate then your bike did not come from the factory with ABS. The peg plates for ABS bikes don't have the inverted V part (to keep passenger feet away from tire.)

(https://i.imgur.com/kMLbzZr.png)

(https://silodrome.com/wp-content/uploads/2015/06/BMW-K75-12.jpg)
Title: Re: 1994 K75 Rear brakes ABS? Reservoir?
Post by: frankenduck on May 30, 2024, 03:51:45 PM
Another way to tell if a K75/K100 ever had ABS is to look inside of the tail cowl. The black "wedge" of an ABS bike will have a large hole in the back of the wedge where the wiring went through to the ABS control unit. Non-ABS wedges do not have that hole.

(https://i.imgur.com/EX7zlgY.jpeg)

Title: Re: 1994 K75 Rear brakes ABS? Reservoir?
Post by: Martin on May 31, 2024, 01:39:04 AM
Be aware the master cylinders are fine however the supply hose from the reservoir may be vacuum hose and can disintegrate. The end result could be brake fluid over your rear tyre.
Regards Martin.
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