OK, I've got a front and rear set of 2010 Deore brakes. The bike was left in a shed for a couple of months when something newer and shinier came along, and when I returned to the bike both brakes were squidgy.
I bled the brakes per the instructions (down from lever to caliper until the bubbles stopped at both ends), and performance returned albeit temporarily. However, leaving the brakes for any more than around ten minutes returns them to softness. Given that this happens on both front and rear brakes, is it likely a technique thing leaving air in the system or are my brakes goosed?
The Avid Juicys that were in the shed at the same time are fine, and similarly I've never had any problems with another, far older, set of Shimano brakes - 7 years old and never bled.
