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If you leave it clamped overnight most if not all of the air should be gone.
Then leave the bleed nipple closed and pump the fluid in to push out the pistons. It should not use that much fluid.
If you remember how far our the pistons were when you started that is how much fluid will be required. One bottle should be plenty.
Once they start to bite, you may have to bleed them a little more to get rid of the last bit of air.
Okay leave the bleed nipple ope, the master cylinder cover open and the lever pressed in overnight or just the lever pressed in overnight? 😜Thank you so much for helping me with this. 🙏
Last edited by kylehasyourfrenchtoast; Jul 4, 2023 at 04:21 PM.
Close the bleed nipple.
Leave the top off the reservoir.
Clamp the lever, leave overnight.
Start pumping again in the morning and eventually the pistons will clamp on the disc.
After that you might have to bleed a little to remove the last of the air.
Would you suggest the culprit is having an eBay front brake lever master cylinder?
the OEM is much larger and maybe will bleed right away? All of the caliper rebuild videos move on to bleed and finished. They don’t mention the long amount or large quantity of bleeding.
I say this in dénouement of having a matching hydraulic clutch master cylinder and was defective and didn’t flow. This front brake lever has never had issues.
Last edited by kylehasyourfrenchtoast; Jul 4, 2023 at 10:19 PM.
Shouldn't really be an issue. If it was working ok before then it should be ok for now.
I suppose it would depend upon how far back the pistons have been pushed back that would determine how long the bleeding would take.
Some folk also use pressure bleeders to carry out this task so may be easier than manually doing it.
Okay AI1040. The process I followed was pushed air to get the pistons out. Coated the chamber and pistons before placing back in the caliper and they were flush. Maybe I should pull the pistons off and leave a bit of a gap for fluid to pull into? Have you ever rebuilt these I couldn’t get the brackets off and the rebuild kits come with those boots. Could try that if the pistons don’t place pressure on the brake pads; pushing the pistons out as they were when the pistons were taken out of the caliper AI1040. My mistake. 🤨😅
Everything seemed fine until you stated that you could not get the brackets off, they should separate and slide freely on on the pins, you brake performance will be severely restricted if they are not able to move on the pins. The boots are to protect the pins when greased to ensure that it is free to move.
If not, make sure you:
1. Pull the lever a few times to build up pressure - hold it pulled.
2. crack the bleed nipple and immediately close it
3. release the lever
You will get to a point where more and more pressure is getting built up in the lever - but you must NEVER pause with the lever entirely pulled with the bleed nipple open, or release the lever with the bleed nipple open - you want the release of the lever to pull more fluid into the master cylinder, not more air into the caliper.
Most people open the bleed nipple and frantically pump the lever - that's not how it's done.
Additionally, in addition to proper squeeze-open-close-release procedure, you're also fighting laws of physics. Bubbles are rising from caliper to MC at same time you're trying to force them down with new fluid. Depending upon how quickly you can do each cycle, bubbles may rise faster than you can push through new fluid.
One way I've found that works 100% of time in more leisurely fashion is not to fight physics. Make bubbles move in direction you want naturally, from MC to calipers. I do this by placing calipers above MC by putting them on shelf on ladder over front-end of bike. Then I can take my time squeezing-opening-closing-releasing without worrying about bubbles working their way back to MC. You'll notice fluid in catch-bottle runs clear after couple squeezes. Can dump old stuff and can re-use new fluid. Typically doesn't require more than 1/2 bottle of new brake-fluid to bleed system using this method anyway.
