Vibration damper unit

A method for assembling a vibration damper unit, said vibration damper unit comprising at least one tube member having an axis and two ends and defining a cavity therein, a piston rod guiding and sealing unit adjacent a first end of said tube member, a piston rod member extending in axial direction through said piston rod guiding and sealing unit, a piston unit connected with said piston rod member inside said cavity and slidably movable along an internal circumferential surface thereof, a bottom valve unit provided adjacent a second end of said tube member, two working chambers inside said cavity, namely a first working chamber axially between said piston rod guiding and sealing unit and said piston unit and a second working chamber axially between said bottom valve unit and said piston unit, said piston unit being provided with piston unit valve means and said bottom valve unit being provided with bottom valve means, a collector space adjacent said bottom valve unit on a side of said bottom valve unit remote from said piston unit, said working chambers and at least part of said collector space containing a damping fluid, said bottom valve unit being axially positioned adjacent said second end of said tube member by a positioning sleeve member, said positioning sleeve member being adjacent said internal circumferential surface of said tube member on an axial side of said bottom valve unit remote from said second end of said tube member wherein said bottom valve unit being disposed between said sleeve member and said second end of said tube member,

• the method comprising the steps of:
• a) providing said tube member;
• b) slidingly introducing said bottom valve unit and said positioning sleeve member into said tube member along said internal circumferential surface with said bottom valve unit preceeding said positioning sleeve member during an introduction movement in an axial direction toward said second end;
• c) securing said bottom valve unit, by said sleeve member, against axial movement under predetermined operational or preoperational conditions;
• d) introducing said piston rod member and said piston unit into said cavity;
• and
• e) closing said cavity at said first end thereof by attaching said piston rod guiding and sealing unit.

A method of disassembling a vibration damper unit, said vibration damper unit comprising at least one tube member having an axis and two ends and defining a cavity therein, a piston rod guiding and sealing unit adjacent a first end of said tube member, a piston rod member extending in axial direction through said piston rod guiding and sealing unit, a piston unit connected with said piston rod member inside said cavity and slidably movable along an internal circumferential surface thereof, a bottom valve unit provided adjacent a second end of said tube member, two working chambers inside said cavity, namely a first working chamber axially between said piston rod guiding and sealing unit and said piston unit and a second working chamber axially between said bottom valve unit and said piston unit, said piston unit being provided with piston unit valve means and said bottom valve unit being provided with bottom valve means, a collector space adjacent said bottom valve unit on a side of said bottom valve unit remote from said piston unit, said working chambers and at least part of said collector space containing a damping fluid, said bottom valve unit being axially positioned adjacent said second end 0f said tube member by a positioning sleeve member, said positioning sleeve member being adjacent said internal circumferential surface of said tube member on an axial side of said bottom valve unit remote from said second end of said tube member wherein said bottom valve unit being disposed between said sleeve member and said second end of said tube member,

• the method comprising the steps of:
• a) removing said piston rod guiding and sealing unit from said tube member before or simultaneously with
• b) withdrawing said piston rod member and said piston unit from said cavity through said first end of said tube member;
• c) introducing a withdrawal tool into said cavity through said first end of said tube member;
• d) engaging said withdrawal tool into an engagement location of one of said positioning sleeve member and said bottom valve unit;
• and
• e) withdrawing said positioning sleeve member and said bottom valve unit from said cavity along said internal circumferential surface with said positioning sleeve member preceding said bottom valve unit during withdrawal movement in an axial direction towards said first end.