How to replace roller bushing

Instructions :

In the Spectra melangers, the roller bushes will wear out after a year or two, and is normal. We recommend replacing it every two years or sooner, and where not possible to replace, you may replace the entire rollers as a pair.
The basic concept is the same for all the models. We are introducing in the near future a newer type of bushing where it is very easy to replace the bushing without any tools or machine shop access .. Until then, the the following is the procedure to replace bushing.
We normally use hydraulic presses like in Picture 9 to remove and to press a bushing. However, if such a facility is not available, then, one can use a hammer to remove and press in a bushing, as shown in images 1 through 8 (or a reamer on a lathe to take it out). Also, a chisel and rod may be used to remove the bush head from the old roller if needed (as shown in pic 2).
If the bushing is slightly larger to fit the hole in the stone rollers, it may be gently filed or (reduced on a lathe) for a tight and perfect fit.