AHP Merkle designs the cylinders in such a manner that under normal conditions there is no drag flow pressure. However, in unfavorable operating conditions it is possible for a drag pressure, which is higher than the pressure in the cylinder chamber, to build up on the rod end.

This can happen, for example, if external forces cause the piston rod to retract in such a way that the seal is not able to return the leak oil – e .g. due to vibrations or impacts. If the drag pressure increases excessively, damage to the primary seal and thus failure of the sealing system may result.