The middle o-ring on the bolt is one of a number of points in the Quest's bolt kit where air from the HPR and air from the LPR are separated just by the o-ring. If one of these o-rings leaks, then HP air will mix with the LP air, causing the pressure to rise. So that is the reason for your problem.
Why is the o-ring appearing to seal after one cycle of the bolt? That's a little less clear cut. Possibly the cycle of the bolt is causing grease to redistribute throughout the bolt kit, and that is helping the o-ring to then seal better.
Another possibility is that the LPR itself is the cause of the spike. The LPR piston uitself may be slightly stuck prior to completing a cycle. This could lead to the LPR core staying open longer due to the piston not moving away from it as pressure builds. The pressure could rise above the normal setting prior to the piston moving away from the LPR core, and the core closing off the air supply to set the pressure.
Last edited by Uziel Gal : 09-16-2009 at 06:53 AM.