I own three trucks with stock Huck brakes and all of them have a brake pedal return spring. That spring in the master cylinder is not strong enough. You need one even if that is not the cause of your problem. Based on your symptoms, I think 3B has it right. It sounds like you don't have enough of brake pedal free play. You need to adjust the master cylinder to allow it to release the hydraulic pressure on your system. Good luck,
Kent

Last edited by Lightholder's Dad; 07/26/2018 1:36 PM. Reason: clarification
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