New brakes, new bleed queries

[tig5]

Hey guys,

I received the levers discussed on this thread: http://ridersofvision.net/rovforum/index.php?topic=14907.0

So far, so good. The build quality looks quite acceptable especially considering the price. There is a microswitch on the brake and clutch and the clutch perch has a threaded hole for a wing mirror.
The length of the levers is comparable to the ones I took off so that is no longer a concern. The adjustment switches operate well but I get the feeling I'll be using them on the setting that positions them closest to the bars. If anyone else wants any more specifics about these units let me know.

Attempting my first bleed and I could only get fluid to come out of one of the callipers. I've checked the bleed valve and it seems clear so I'm figuring it just might be a slow process of drawing fluid down the other line. I did some researching and I see that some people use a specialized vacuum system to achieve this and others have had success by sucking on a piece of tube attached to the bleed valve. I'm reasonably inexperienced in the sucking department so I was wondering if a large gauge syringe attached to the valve might be useful for sucking fuid down? Anyone else got any other methods? I squeezed away on the lever for half an hour, one calliper bled almost instantly but the other hasn't shown any action at all.

I was also wondering about the size of the air bubbles that is acceptable. The calliper that did bleed did so pretty easily and I was using a different colour brake fluid so it was easy to see the change. I cleared a few bubbles that were roughly the same diameter as the bleeding tube, then the fluid that followed just contained a few tiny bubbles not much bigger than a pinhead. Are these little guys ok or do I need to bleed it completely clear?

Cheers

[The Prophet of Doom]

I used to fart around with vacuum pumps for bleeding difficult calipers, but now I just use a 2 meter length of clear plastic hose.
2m is long enough to stand up and fill the mc while sucking, and also be safe from ingesting it.  I use new tube each time - it's fairly cheap.  Also, I use PTFE thread tape on the bleed nipples - otherwise using vacuum just pulls air in through the threads.


You may need to bleed several times a day apart when doing a full rebuild eventually there should be no air bubbles at all.  Each bubble makes the braking a little softer since air will compress whereas fluid won't.

[Rikugun]

Another thing you can try is using the large gauge syringe to evacuate the MC. Then, use it and appropriate sized tubing and fill the system from the caliper bleeders up. Use zip ties to seal the tubing on the bleeders if need be. You'll force air ahead of the fluid until the MC reservoir is full. Usually I'll follow with conventional bleeding once more to verify pull. You might want to adjust the lever throw out for this procedure for more MC piston travel.  :)

[tig5]

Great info as always, cheers chaps.