Brakes not releasing

[street]

So after brakes fully stuck on, rebuilt remote servo I worked out the new willwood master brake cylinder install angle was causing it to bind and stay on, all fixed with a few washers to Make it sit vertical. Now the next problem on my short test drives I brake with good pedal movement when I release the pedal the brakes stay on for what feels like a couple of seconds and then they release. I recall reading about installing one way valve off engine head, anyone remember if this is correct or have something else to offer. Thanks

[alan.barker]

What Servo have you fitted. The Servo has to be at a certain angle to allow the Air Valve to release. Some owners have added a light Spring to help release.
Alan