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Putting fluid in new empty brake lines

Discussion in 'Technical and Troubleshooting Torque' started by mattb, Oct 30, 2008.

  1. G'day All.

    Bleeding lines is a topic about which there are many threads, and something I've done easily in the past, but I've a slightly differnt problem. Fitted a braided line to by front brake today, and can't get any pressure in the brake. I don't know if there's a proper technique for putting new fluid into an emply line (as opposed to putting new fluid in on top of old fluid) so here's what I did: replaced the line, bolted soundly at both ends (had checked that the hole in the banjo was level with where it was on the old banjo). Undid the nipple on the caliper and started pumping the brake lever and putting new fluid in the reservior. Came out the nipple in no time. While the lever was depressed, with fluid trying to spill out of the nipple, I closed it. Then I pumped for a while expecting either to feel resistance or see the reservoir level decline. Neither happened. Bubbles for a bit then nothing, but still no resistance. Any suggestions at this point? I'm thinking trapped air in the line maybe...

  2. You often can't pump it through with the master cylinder whilst there is so much air in the system. I use a big horse syringe with a small length of clear fuel line on it attached to the bleed nipple on the caliper and fill it one syringe at a time till it reaches the master cylinder. Get one from your vet or chemist.
  3. i did this on a DR600 a year or so ago, or maybe a KLX, anyhoo i spent near on an hour flicking the brake leavel to get the little bubbles, hundreds of them, took a long time.. then i got a plastic syringe, small hose and put it over the brake bleed nipple, and one hand on the spanner to open the blee valve and the opther to depress the syringe (full of fluid) then as the fluid is almost all pushed from the Syringe into the brake line, clamp off the nipple.. refil syringe, repeat, until the fluid is coming up in the master cylinder resivor receptical on top.. some rags around the bars to stop spillage etc.. and the air is pushed up in front of the fluid.. works quick adn well.
    there are systems for doing it, I htin about $100, mabye someone has one?

    good luck al
  4. Geniuses!

  5. Seen a couple of people having issues doing this so I thought I'd make my first post a useful one to say hi.

    Here goes...

    The fastest, easiest and cheapest way to to this is with a vegemite jar, some clear plastic tube from the hardware the right size to go firmly over the bleed nipple and an old compressor out of a fridge.

    The compressors also draw vacuum on one line and they're FREE!!

    So you've got one line from the bleed nipple goes through the lid of the vegemite jar to the bottom where you put a little bit of fluid so it's immersed at the bottom. The other tube to the compressor /vac pump just goes into the lid a little.

    Fill the brake reservoir completely switch on the compressor then open the bleed nipple.

    Keep a check on the level in the reservoir so you don't empty it and put air into the lines again.

    Did this recently when I replaced the all of the brake lines on my tintop. I can't remember if I needed someone pumping the brakes or not.

    Two people, one checking the line from the belled nipple to the jar for air once the fluid starts to flow and switching the vac pump on and the other person to work the brake lever and keep a check on the fluid level in the reservoir.

    Check on the net for details on wiring the compressors as bigger ones need the start capacitor to kick over and some don't like being restarted immediately after being switched off.

    In this case closing the bleed nipple will stop the reservoir draining and the vac pump will chug away happily.

    This is a really quick way to change all of your fluid also just by inspection of the colour change through the clear tube.


  6. Tried it this evening with a syringe and tube, first draining the lines and reversing the entry point as recommended. With this method the whoe job took about ten minutes, and the actual task itself about one or two minutes, and worked perfectly!

    I took the bike for a quick spin to check the brakes. Didn't brake too hard as I was wearing no other gear than my pudding basin helmet and it was wet, but the method worked, and it seemed as though the brakes were more sensitive - go the braided lines! I've had the brakes fade badly on several occassions toward the end of a long hot ride, looks like the 30 year old rubber was to blame. Any way, if anybody's looking for cheap braided lines, I got mine for $30 here http://stores.ebay.com.au/Motorcycle-Parts-Worldwide