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Can't get the brakes to bleed

Discussion in 'XJ Technical Chat' started by corner27, Jun 17, 2008.

  1. corner27

    corner27 Member

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    I have been trying to bleed the brakes on my 80 XJ650 maxim. I put a long clear hose on the bleeder screw and put some brake fluid in it. I pumped the brakes, and worked all the air out, and the darker color of brake fluid in the resivoir worked it way to the bottom and out that hose. I closed the bleeder screw, and pumped the brakes a bunch, it gets a tiny bit tighter, but not alot. If I spin the wheel and apply the brakes it will slow down, but it's not a sudden stop like it should be. Is there something I'm doing wrong??
     
  2. Altus

    Altus Active Member

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    You've still got air in there I'm afraid -- one trick that sometimes works for those last few air bubbles is to open the bleed screw, squeeze the brake lever right to the bar, then close the bleed screw and tie the brake lever there (at the bar). Elastics, cords, rope - whatever. Then leave it at least overnight or more.

    When you come back, remove the ties and give it a few pumps. I've seen this one work to firm the lever right up.
     
  3. corner27

    corner27 Member

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    Does it matter of the resivoir cap is on or off?
     
  4. Altus

    Altus Active Member

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    Nope - in fact on would be better - no chance for moisture to get into the system
     
  5. MiCarl

    MiCarl Active Member

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    Maxims tend to trap air because of the rise out of the master cylinder. You can minimize this by having the motorcycle on the center stand and the bars turned all the way to the left.
     
  6. BlueMaxim

    BlueMaxim Active Member

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    Just to make sure that what I read is what you are doing. You state that you attached the clear line and opened the bleeder screw, pumped the brakes then closed the bleeder screw. You should be opening the bleeder screw, pulling the brake lever in, holding it in and closing the bleeder screw. Unless you have speed bleeders instead of stock bleeder screws you have to close the bleeder screw before releasing the brake lever. Not doing so will suck air back into the system through the open bleeder screw. You also have to make sure the reservoir doesn't get low on fluid or you will suck in air from there.
    I use a Mity-vac to bleed my brakes and it works like a dream! Speed Bleeders are about 1/3 the price of a Mity-Vac and work even if you don't have the tool box with you since they mount on the caliper.
     
  7. wizard

    wizard Active Member

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    put a snug fitting ring spanner on the bleed nipple, then the tube, loose end into a jar, squeeze the brake lever, then turn the spanner, this way you feel what is occuring, hold the lever and tighten the nipple. repeat, nice steady pulls, allow 20 mins for each calliper, if you get the air out quicker than that, great. i can't see how you can do it with the cover on, you must pay attention to the fluid level, don't let it get below half.
     
  8. Polock

    Polock Well-Known Member

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    you can do it without closing the bleeder each time, it just takes more pumps
    but they go faster
    put some teflon tape on the bleeder threads, just on the threads, so no air goes in that way
    do like Altus said give any bubbles a chance to come to the top, you want that to be the master cylinder
     
  9. RickCoMatic

    RickCoMatic Well-Known Member

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    I wrap the Bleed Nipples threads in Teflon.
    I use a One-way Valved "One-man Bleeder'
    I put Brake Fluid in the collection jar and submerge the One-way Valve.
    I Open the Bleed Nipple with the hose attached.
    Fill the Master to at least half and keep it filled at least one half.

    I pump the lever and force the fluid out the One-way Valve until it is as clean coming out as the new stuff in the Master reservoir.

    Once the clean fluid shows-up in the Bleeder Line I begin pressure pumping.
    Close the Bleeder
    Pump the laver slow a few times then HOLD it with steady closing pressure while the Bleed Nipple is opened.

    When the Lever hits the Throttle Grip ... Hold it steady and close the Bleed Nipple.

    After a few Pump-ups and Pressure releases ... all the air is out and Brake Pressure is returned to the system.
     
  10. wizard

    wizard Active Member

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    you can do it without closing the bleeder each time, (quote)

    if it is a standard bleed nipple, that is just plain wrong. :!:
     
  11. Ease

    Ease Member

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    Try slowing down the speed of the pumping.
    ...Nice and slow, crack open the bleeder... let some come out, tighten it up, release, repeat.

    I was having the same issue, then I slowed it down and it worked fine...
     
  12. Hillsy

    Hillsy Member

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    Many years ago, a bike mechanic showed me his method of using a 20CC syringe with a small tube. He pumped the fluid through the bleed nipple back up to the resevior. All bubbles gone in seconds.
    I've used this method for years and it has worked EVERY time. Even on linked brake Guzzi's and servo assist BMW's.....

    This method works on the principle that air bubbles rise in a fluid – so you are working with gravity (rather than against it) to eject any air through the reservoir. The bleed nipple on the caliper is usually the lowest entry point in the brake line system, so this is the point where the fluid is introduced.


    1. Go to the local chemist and buy a 20cc syringe. Tell them it’s not for drugs. These are about $1-2 each (the syringes, not the drugs).

    2. Get yourself some clear hose – the same stuff you probably have used for normal brake bleeding duties. Cut a piece that’s about 10-15cm long and push this on the end of the syringe. Now you are ready.

    3. Open the reservoir cap and suck out the old fluid (if any) with the syringe and tube. Discard this fluid.

    4. Place a suitable ring spanner on the caliper bleed nipple (normally 10mm). Make sure it has enough "swing" room to open and close the nipple (about one third of a turn).

    5. Fill the syringe about 3 quarters full with fresh fluid (straight from a new bottle). then hold the syringe upright and draw some air into it, clearing the tube of fluid.

    6. Push the tube over the bleed nipple. Facing the syringe down, open the nipple slightly and draw a SMALL amount of fluid out of the caliper with the syringe. This will fill the tube with fluid and allow any air to rise to the top of the syringe. Don’t draw too much or you will suck air into the master cylinder.

    7. With the caliper nipple still open, push the fresh fluid from the syringe into the caliper. Be careful not to push any of the air from the syringe back into the caliper. When this is done, close the nipple and remove the tube (a good tip here is to close the nipple and draw the syringe – creating a suction effect in the tube over the nipple. Remove the hose and any remaining fluid will be sucked back into the syringe. Nice and tidy).

    8. Repeat the process from step 5. Keep an eye on the reservoir level – if it approaches full, use the syringe to remove the fluid as per step 3 (if you’re stingy enough, you might re-use this fluid for your next attempt at step 5).

    9. If you have twin calipers, move to the other caliper and start the process again from step 5.


    You can also use the syringe to draw fluid out of the caliper. This is handy when you are bleeding the system from dry, as there will be air in the caliper above the brake line entry point that you won’t be able to push back up the line.

    With a bit of practice, you will find that this method is the quickest way to bleed a brake system – and you will use minimal brake fluids in the process.
     
  13. RickCoMatic

    RickCoMatic Well-Known Member

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    If you aren't getting pressure built-up, you night need to rebuild the Master Cylinder and put a new Seals Kit in there.

    When the Seals are worn-out, the brake lever pulls without developing hydraulic pressure becausue the internal seals are leaking-by.

    A Kit for rebuilding the Master Cylinder has all the Seals and other parts and is a pretty straightforward exchange.
     
  14. corner27

    corner27 Member

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    I figure it out. Well, with may peoples help that is. I put teflon tape on the bleeder screw, and now it built up pressure. I must have been letting air in.
     
  15. Polock

    Polock Well-Known Member

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    not doing the loosen tighten thing might be wrong but it sure works
    demo
     
  16. TIMEtoRIDE

    TIMEtoRIDE Active Member

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    Time for 2 more techniques !

    1--My 750 didn't bleed, or make pressure, until I put a long clear tube on a caliper bleeder, and sucked with mouth vacuum. I also had a 3 foot clear tube on the resivor filler (the fork mount master cyl) full of new fluid.

    2--The "Redneck" bleeder trick. Cost $0 . Just crack open a beer with your left hand, and crack open the bleeder and put your right thumb on it, and slowly pump the brakes. You will hear the air squirt out, along with brake fluid everywhere. Makes a big mess. This method won't bleed a dry system.

    + 1 on Polock's "demo"
     
  17. flash1259

    flash1259 Member

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    I had the same problem took off the plastic hose off the bleeder filled the reseviour and open the bleeder walked away got a soda a few minutes later it was dripping . then i was able to actually bleed the air out . they work good now.
     
  18. wizard

    wizard Active Member

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    Hey TIME to RIDE you got any pictures of that method?
     
  19. corner27

    corner27 Member

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    I finally got it. I got fed up and ordered a Speed Bleeder. It's pretty much a bleeder screw with a one way valve. I was amazed! I pumped through about 3 resivoirs full and tightened the bleeder and the lines were instantly full of pressure. I couldnt believe it. Well worth the $7!!
     
  20. TIMEtoRIDE

    TIMEtoRIDE Active Member

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    Here's the set-up. Just masking tape, clear tube, and a funnel.
    Keep that brake fluid off your paint !
     

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