Slightly off topic but, when I first apply the brakes after starting the engine there is a noticable “clonk” from the dual servo. This only happens the once and does not recur until after the engine is next started. All mounting bolts, clevis and pedal bolt have been checked and are secure. The servo operation remains the same and braking efficiency remains the same i.e. brilliant!
As a theory: The diaphragms seem to be on two in-line but physically separate push rods. I guessed this from the fact that before fitting the unit I could move the primary push rod sideways (when fitting the clevis over the fixed pedal bolt) which would not be possible if the rod was attached to both diaphragms. I wonder if there is more residual vacuum in one sevo chamber than the other so that as soon as the engine starts and supplies more vacuum, pressing the pedal makes one of the diaphragms respond a little faster than the other to take up the slack. Has anyone else noticed the same? Peter.