A long sleeve cartridge for being inserted into a fluid end block of a pump is disclosed. The long sleeve cartridge includes a body and a sleeve bore extending through the body. The sleeve bore includes a first inner diameter and a second inner diameter. The first inner diameter is less than the second inner diameter. A first aperture is located on the body, and a second aperture is located on the body in a radial position substantially diametrically opposite of the first aperture. A packing seal assembly is secured within the long sleeve cartridge. The packing seal assembly includes one or more seals and a biasing mechanism to provide a compression force on the seals. The packing seal assembly is arranged within the second inner diameter when the packing seal assembly is disposed within the long sleeve cartridge.