A monotube shock absorber which is capable of high compression damping forces while operating at low pressure for reduced friction is disclosed. The monotube shock absorber includes a pressure tube, a piston assembly, a piston rod, a fixed valve assembly and a floating piston. A variety of methods for securing the fixed valve assembly to the pressure tube are disclosed including use of single piece pressure tubes and pressure tube assemblies. In addition, a method for assembling the monotube shock absorber including an oil filling technique is described.