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bleeding the clutch

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ok so i want to bleed my clutch and make sure there is no air in it. i am riding a 08 250 xc and it has the brembo clutch that runs on motrex dot 5.1 brake fluid. how do i bleed it just like brakes ? squeez the lever open the bleeder then close it when fluid is done flowing out?

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You can do it that way so long as you don't get any air in the system then you would need to back or power bleed to get out the air bubble.

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It is hard to bleed that way because you are trying to push air bubbles down hill and they tend to go up so using a syringe bleed from the bottom up.

  1. It helps to make sure there is no high spot in the line. Pull any section of line that is higher then the master cylinder down so it is uphill all the way from the slave to the master cylinder. Usually the problem section is above the handlebars. Air goes up and air bubbles can be trapped at any high spot with fluid moving by but the air staying put. You can overcome this in a small line by moving the fluid so fast that it carries the air with it but you probably wont do that with a syringe.
  2. Push some fluid out the hose on your syringe bleed rig so their is no air in the hose. Like a doctor does it on TV when he squirts some fluid in the air before giving a shot so he doesn't inject air into someone.
  3. Clean out the bleed screw. Don't pump dirt into the system. Remove it to clean if necessary. Keep it covered with a plastic cap to avoid this.
  4. Connect the hose from the syringe to the bleed screw. Make sure it is tight enough to not leak. It shouldn't take much pressure to do the bleeding but depends on the size of your syringe.
  5. Open the bleed screw (unscrew a turn or so).
  6. Push fluid into the slave cylinder forcing it up into the reservoir (the cover must be off on the reservoir too). Continue pushing fluid through the system until no more air bubbles are coming out in the reservoir.
  7. Close the bleed screw before removing the bleed hose/syringe or letting up on the plunger (pressure).

You might have to bleed both way (up and down. You might have to bleed down after bleeding up in order too to get the last little air bubbles out of the bleeder and top of slave cylinder because the bleeder is on top.

When bleeding down it is just like bleeding the brakes on an automobile:

Note: bleeding down doesn't usually work to get air out of the whole system and is best for last, after bleeding up, for just getting out any air trapped in the slave cylinder IMO. Since the bleed screw is on top of the slave cylinder a little air can be trapped there after normal bleeding up with a syringe. If you really screw this up and let air back in the system you need to start over with bleeding up.

1. Start with the reservoir full and bleed screw closed (screwed in all the way tight or snug). If the reservoir goes empty while bleeding this way you push air in instead of fluid and you have to start over with bleeding up.

2. Pump/pull the lever a couple of times and then pull it in all the way and hold it.

3. Open the bleed screw and let air and fluid out (don't use the syringe for this, however you can run a hose into a cup of fluid to prevent air getting back in and then you can pump the lever. In your case don't because you can't seem to get the hose/syringe set to not leak).

4. Close the bleed screw (don't pump or let up on the clutch lever until the bleed screw is closed again or you will let air back in).

5. You may have to repeat starting from step one several times until no air bubbles comes out.

If you have the whole system apart it is easier if you bench bleed everything first, the master and slave cylinder, and the line, while you have everything apart. That means put everything together with fluid in it and air purged out. Then you don't need to transfer as much fluid during bleeding. It is not necessary when bleeding up, but still nicer and less work. It also lets you know if fluid is moving through things like the master cylinder if you are having problems.

Gary

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