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made a rookie brake bleed mistake


MachineJoe

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I need advice on what to do next.  Here's the lead up to my mistake

I removed both front brake calipers and brake pads from the calipers and cleaned everything thoroughly. Then I suctioned the old fluid out of the reservoir and proceeded to push back the 8 brake pistons. After that I blocked the pistons and filled the reservoir with fresh fluid. I proceeded to mount the right side caliper and put the brake pads in place and started pumping the new fluid as one would normally do.

This is where the error took place.

On the far (left) side as i was pumping the brake, the block that was holding the pistons in place moved/slipped enough to allow one piston to push out completely and fluid was dumping out of the ejected piston. I reinserted the piston and needless to say had a ton of air to purge out. After I thought all the air was purged I still don't have a solid feel from my brake lever.

I've stopped working on it as my brain needs a brake  (haha)

any suggestions?

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Ouch.....

Me personally would now turn the the handlebars to the left until the main reservoir is as level as possible. Take the brake reservoir lid of and tie the handle back as far as it will reasonably go. Use velcro or even a plastic cable tie that you can cut off later. Leave it like that for a day/night. This will help any air-bubbles that are trapped in the line to rise and escape via the reservoir.

 

 

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10 hours ago, MachineJoe said:

I need advice on what to do next.  Here's the lead up to my mistake

I removed both front brake calipers and brake pads from the calipers and cleaned everything thoroughly. Then I suctioned the old fluid out of the reservoir and proceeded to push back the 8 brake pistons. After that I blocked the pistons and filled the reservoir with fresh fluid. I proceeded to mount the right side caliper and put the brake pads in place and started pumping the new fluid as one would normally do.

This is where the error took place.

On the far (left) side as i was pumping the brake, the block that was holding the pistons in place moved/slipped enough to allow one piston to push out completely and fluid was dumping out of the ejected piston. I reinserted the piston and needless to say had a ton of air to purge out. After I thought all the air was purged I still don't have a solid feel from my brake lever.

I've stopped working on it as my brain needs a brake  (haha)

any suggestions?

Morning   MachineJoe

 

Tell us more__ At any time did your master cylinder reservoir run low on fluid or go dry?

 

Is the caliper that the piston popped out of still hanging free with a block in it or is it now reinstalled? If still free make sure the caliper it is sitting at about the same angle that it would be mounted at (or at least the bleed nipple is at the top). 

 

When you pushed that piston back in you probably pushed a pretty good slug of air back up the brake line so you have to get that out.  

 

Try pulling the front brake lever as far as possible with just your finger tips, then when in as far as possible allow the lever to slip off your finger tips & snap back out with speed (do this a few times) then re-bleed.  Sometimes allowing the compressed lever/compressed air in the fluid to quickly un-compress & move will allow it to then bleed out.

 

 

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2 hours ago, dirtrider said:

Morning   MachineJoe

 

Tell us more__ At any time did your master cylinder reservoir run low on fluid or go dry?

 

Is the caliper that the piston popped out of still hanging free with a block in it or is it now reinstalled? If still free make sure the caliper it is sitting at about the same angle that it would be mounted at (or at least the bleed nipple is at the top). 

 

When you pushed that piston back in you probably pushed a pretty good slug of air back up the brake line so you have to get that out.  

 

Try pulling the front brake lever as far as possible with just your finger tips, then when in as far as possible allow the lever to slip off your finger tips & snap back out with speed (do this a few times) then re-bleed.  Sometimes allowing the compressed lever/compressed air in the fluid to quickly un-compress & move will allow it to then bleed out.

 

 

Morning DR,

 

the master cylinder never went dry or ran low.

The piston was reinstalled and the caliper was mounted, after that I spent quite some time bleeding the air out through the speed bleeders

I did set my brake lever as Alfred02 suggested last night and this helped a lot as I have a fairly rigid feel to my brake lever now.

I’ll try your suggestions at lunch time.

Thank you DR. and thank you Alfred02 for your suggestions

 

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All is well with my bike. I took it out for a ride just now and there’s no runs, drips or errors

A tip-o-the-hat to Alfred02 and DR for their advice and Boxflyer for making and posting the video series 

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