Yes, follow the instructions on the B4 instructions to the letter. They need a little air in them, and for them to rebound slightly.
You can download the B4 manual from associated's website:
www.rc10.com
Alternatively, you could put a small bleed hole and screw (the hinge pin retaining ones are fine) in the cap, but you will need to drill the cap, which is not easy.
HTH
Mark