One thing you can try is pounding on the bars to try to vibrate any bubbles up into the reservoir. Just an idea. It has worked for me in the past.
It sounds as if you are sucking air into the line when letting go of the lever. It could just be a coincidence with regards to timing. You might just have a bad seal.
It sounds as if you are sucking air into the line when letting go of the lever. It could just be a coincidence with regards to timing. You might just have a bad seal.