Brake Fluid replacement and bleeding front brake on Honda Rebel 250
Noticed that the brake fluid was getting kind of brownish and bit low in a small window of the front brake fluid reservoir. So I decided to tackle this task on my own. Have to say all in all it was easier to do then changing oil on my rebel (damn that oil drain screw !). I started by wrapping an old rag around the reservoir as the brake fluid can easily damage paint and chrome finish of the motorcycle.
Before opening the reservoir I placed the wrench over the brake fluid bleed nipple (on the caliper), and connected the plastic see through tube from the brake bleeding kit. The bottle came with a magnetic holder. Note that I positioned it ABOVE the caliper, so if there are any bubble in the brake fluid that is being bled, they would rise up in to the bottle. Also I pre-filled the bottle with some old brake fluid, so by accident I don't get air sucked in when starting the bleeding process (see below).
Then I removed two screws which hold the brake fluid's reservoir's cover in place (pic below)
With the cover out of the way, I removed the white plastic diaphragm retainer
Then I removed the flexible (black rubber) diaphragm, noting it's orientation (there is a top and the bottom).
Reservoir cover parts in the picture below:
Diaphragm, white plastic diaphragm retainer, metal cover (left to right) and the two cover retaining screws below:
With the reservoir open I began the brake bleeding / fluid replacement.:
1) Pump the brake lever 3 times,
2) Hold the brake lever ... open the bleed nipple 1/8 of a turn to the left
3) Watch the brake liquid start flowing thrugh the tube.
4) Close the bleed nipple - 1/8 of turn to the right (not too tight)
5) Relese brake lever and pump it 3 times untill it's nice and firm
Then repeat: open bleed nippple, watch the brake fluid flow in to the bottle, close bleed nipple, let go of the lever, pump the lever 3 times to build up the pressure, hold down ........ (wash and repeat )....
While doing that I made sure that I didn't totally emptied the resevoir and introduced air in to the brake line and caliper (in pic below old fluid still covers the reservoir hole). In retrosepct that's a bit too clsoe for comfort, I should of added fresh fluid a little earlier)
by topping off the resevuir off with fresh brake fluid (STP DOT 3 ). Brake fluid reservoir cover states to use DOT 3 or DOT 4 brake fluid.
Note the color difference between the old (brown) and the new (almost colorless) brake fluid).
I continued the brake fluid bleeding until I noticed that the color of the fluid flowing in to the waste bottle changed to the color of the fresh brake fluid.
With that I filled the reservoir to the "max" mark with the fresh brake fluid and replaced the diaphragm (noting the proper orientation), the plastic and the metal covers and hand tightened the two screws. A little bit of fluid bled through as I tightened the screws I made sure I wiped it dry before it touched any paint of chrome. I can still see an air bubble, but it should be there so there is enough place for the fluid as it gets hot and expands.
I hand tightened the caliper bleed nipple, making sure not to OVER TIGHTEN it (I understand this are very easy to over tighten and "strip"). Then I disconnected the bleed kit, by lowering the bottle below the caliper level and then disconnecting the tube from the bleed nipple. Wiped the bleed nipple with a rag (getting rid of the drop of brake fluid) and replaced the black rubber bleed nipple cover.
Tried the break lever and it felt nice and firm. Went for a test ride, and the break feels firm and easy to modulate. All the sponginess is gone and the pads bite in with slight pressure of two fingers on the lever. Love it when it all comes together and works as it should.
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