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Brake bleeding and brake questions

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by cuvy, Feb 16, 2006.

  1. Hi,

    Just put some new braided brake lines on the SRX and having a bit of difficulty bleeding the brakes, so i have a few questions:

    What's the best way to flush out the old fluid? I've had the master cylinder open for a few days so i think there's going to be too much water absorbed into the new fluid by now. Should i just open the bleed nipples and pump the brakes, refilling the master cylinder before it gets completely empty? Should i do this with the top on or off the resevoir?

    Is the entire system pressurised, or just the lines? ie., if the lid is off the resevoir, will the system lose pressure?

    The brakes currently work, but are a bit spongey (i guess due to bubbles in the lines). What i've been doing is pumping the brakes, the holding the lever in a bit, loosening the banjo bolt at the master cylinder, squeezing the brake lever in more, then tightening the bolt back up. This squirts out a bit of brake fluid, as well as some air - seems to do a reasonable job of getting air out. Doing a similar thing with the nippes on the caliper didn't have much effect - i guess all the air bubbles have been cleared from the lower part of the system. is this the best approach, or should i still be bleeding from the caliper nipples as well?

    How long do you expect a bottle of brake fluid that has been opened, then resealed again tightly, to last before it's absorbed too much moisture (bearing in mind i'm in stinking hot, humid brisbane...) ?

    Any other tips or suggestions?

  2. Yes

    Off is fine.

    Just the lines

    This is the best approach

    I'd get a new bottle if it's been sitting for longer than around 12mths
  3. Mouth - thanks. The bottles only been open for about a week, so i guess it should be fine.

  4. Now if you still have trouble bleeding up the system remove 1 bleeder nipple at a time place your finger over the hole and pump up system. holding the brake lever in, release your finger and them replace it back over the hole then pump up the system again. do this until the pumping motion wants to blow your finger off the hole. screw bleeder back in and do thwe same to other side, if twin disc. then bleed system as normal. :wink: :wink: :wink: :wink:
  5. head to BigW or Kmart and pay about $15 in the auto spares section for a brake bleeder hose

    its a rubber hose with a 1 way valve in it , stick it on the bleed nipple , crack open the nipple and pump the lever non stop until everything is clear topping up the fluid along the way

    close up and all good :)
  6. Cuvy, I endorse the advice from Johnnie5. I recently bled the brakes front and back on my CBR600FY with no problem at all (and also the front calipers on the car driven by my wife with my two children (only the wife drives, of course)), using a simple brake bleeder kit from Supercheap Auto.

    The kit is basic and uses a clear plastic hose which you attach to the caliper nipple and sit the end in a glass jar or drip tray or ice cream bucket / whatever. Some kits have a one way valve, some don't.

    With the lid off the master reservoir you just start pumping the brake lever - if there is no valve on the hose then you will need a ring spanner on the nipple ready to close off the nipple on each closed brake lever squeeze.

    Let out the brake lever and squeeze again, and on you go. Make sure the master reservoir does not run dry and in no time the fluid and any bubbles should pass through the clear hose and into your jar (or whatever your collection vessel is), and begin to change colour if the new fluid is a different colour pushing out the old stuff - usually the case.

    When you think you're done, tap the top and sides of the brake caliper gently with a hammer (wrap hammer with a t-shirt if concerned about damage to the caliper surface) to dislodge any mischievous remaining air bubbles and do several more pumps.

    Don't skimp on the fluid - once the bottle is open be prepared to blow the lot to get things right.

    If you want practice first, do the (arguably slightly less critical) back brake and become a pro ready for the front calipers.

    If twin disks, make sure you do both sides! A friend to top up the master reserviour and pump up top while you babysit the clear hose on the nipple down below would be better still.

    Good luck.

  7. ITs better to pump it using the method outlined before, if u try using ur gravity method u will end up with bubbles in the system and may be even worse stuffed up master cilynder.
  8. Thanks for all the tips guys.

    I ended up using a clear hose over the bleed nipple on the caliper. Top off the master resevoir and pumped the brakes till the old fluid and bubbles were flushed out (topping up the resevoir as required). Did this for both sides and brakes were done in no time!

    Now that i've got all this practice with the front, i might as well do the rear brakes...