IMPORTANT DISCLAIMER: Brakes are a critical
safety component on motorcycles. This is what I do and
am comfortable with. I do not warrant in any way that
anything about this is the "right" way to set up your
brakes. Only do this if you are comfortable with it
and willing to take sole responsibility for it. If you don't
trust your own skills then you're better off having brake
work done by a certified mechanic.
Over the years BMW made three
different brake levers for K75s and K100s. One of them has a
set screw in it that allows you to adjust the contact point
between the brake lever and master cylinder piston to your
liking. The part number for the adjustable brake lever is
The OEM front braking on 2V K
bikes can be rather anemic even if you bleed them annually
with fresh DOT 4 brake fluid. (Only use DOT 4 brake fluid in your K bike.) Not to mention how overly
complex and dorky the early K bike front brake setup that
goes through the steering head is.
And buying "custom" braided
stainless kits from the usual suspects can be rather
expensive. Here's my solution that I've employed on
K75s and a K100 to make the braking better at a reasonable
It's a very simple system with a
single braided stainless steel brake line from the master
cylinder to the right caliper and then a metal line from the
right caliper to the left caliper. (The metal line is a BMW
part made for later model K75s.)
Here's an example on a K75S:
Parts you'll need:
1) 2 Goodridge 3/8" 35 or 45 Degree
2) Goodridge 26" Universal
Braided Stainless Brake Line (available in clear or black
3) BMW "Brake Pipe" - Part
34322312691 (about $17 in 2018)
1) Remove the rear fender half
and leave the calipers installed on
2) Bleed the system and remove
all of the old brake lines.
If you have the system that
passes through the steering head then that brake pipe with
the Y at the bottom can be removed by undoing the nut at the
top of it and pulling it out from the bottom of the steering
3) Install the BMW metal brake line between the
inner holes on the brake calipers. Get the fittings at the
ends of the metal line tight but be careful not to
over-tighten them and strip the threads in the calipers.
Note that when you put the rear
half of the front fender back on that you may have to bend the metal
line around a bit to get it to fit under the fender. Within
reason, it's OK to do that.
Also make sure that the metal
brake line is not rubbing on the tire.
4) Install a bleed valve in the
outer hole of the left caliper. (Torque: 7 Nm - 62 in-lbs)
5) Using crush washers above and
below a banjo bolt, attach it to the outer hole of the right
There's no need to get it really tight now as you'll later
need to rotate it a bit once you get the line installed.
6) Using crush washers above and
below a banjo bolt, attach it to the bottom of the front master cylinder.
(Torque: 11 Nm - 97 in-lbs) If you don't have a torque
wrench be careful not to over-tighten the banjo bolt and
strip the threads in the bottom of the master cylinder which
will destroy it (A new master cylinder from BMW costs
7) Attach the 26" brake line
between the master cylinder and the right caliper banjo
8) Adjust and tighten everything.
You may want to add a loose zip-tie around the right fork
and the brake line above the lower fork tree in order to
keep the brake line lined up with the fork.
9) Bleed the air from the stainless
line by putting DOT 4 brake fluid in the master cylinder
reservoir and slowly repeatedly squeezing the front brake lever until bubbles stop
appearing. It helps bleeding if you turn the handlebars to
full lock left and then loosen the throttle perch clamp to
rotate the master cylinder until the bottom of the reservoir
In order to bleed the metal line
between the calipers, remove the calipers and hold them with
left caliper above the right caliper so that any air in the
system floats up to the bleed valve. Keep squeezing,
be patient. Top off the master cylinder reservoir,
replace the cover, return it to it's regular position on the
handlebars and then tighten (don't over-tighten) the perch
10) Reinstall the calipers and
rear half of the front fender.
11) Go for a test ride. Before
doing so pump the brake lever a few times to make sure that
the pads are settled on the rotors. When you go for a test
ride be sure to exercise caution.
Your brakes may work much better than before and
squeezing too hard may cause your front wheel to lock up and
wash out. Conversely, if you didn't get all of the air bled
out of the system then your brakes may be softer than you
No hole in the fender for the brake line:
If the rear half of the front
fender doesn't have a hole in it for the brake line to pass
through as pictured above then you'll need to take a
slightly different approach.
You'll want to use a right angle
banjo bolt at the caliper, run the line outside of the
fender and use a BMW brake line holder.
BMW "Cable Holder" Part
61131369668 (about $1)
If you still want better braking
once you've done the above then you can use sintered brake
pads. These have a better "bite" than conventional
organic/Kevlar brake pads but do so at the
expense of the brake rotors wearing down a little bit faster.
© 2018 Drake Smith - Please do
not use or reproduce this elsewhere. Feel free to link
to it though.