Brake Cylinder Hone

I've seen tutorial posts where a dowel with a slot cut cut lengthwise is used in a drill. A strip of sandpaper or emery cloth is slid into the slot and spun in the compression chamber and worked forward and rearward to crosshatch the inner walls. I don't recall what grit paper was used. I chose not to do this when I rebuilt my R9. Some google searching for rebuild how-to tutorials may help. Unfortunately, a lot of really good tutorial info was lost when Photobucket decided to charge for their image hosting. The Yellow forum switching platforms has also made some great info hard to find.

Good luck on your rebuild!
 
The main reason you hone a cylinder is to break the glaze ( shine ) in the cylinder and create a cross hatch pattern where the seal can grab on to and seal. I have rebuilt hundreds of hydraulic cylinders, brake master cylinders and wheel cylinders But no airgun cylinders.

i used a wooden dowel rod on small diameter cylinders and put 2 hack saw blades in my saw and cut a slit down rod about 3 inches long take some 400 to 600 grit wet / dry sandpaper take half or hole sheet according to size of cylinder. Fold the paper up and slide in slot and wrap around rod and oil liberally with a light oil and run it in and out of cylinder to get cross hatch pattern.You can put a zip tie on the end of split on dowel so paper does not come off dowel. The more paper and tighter wound the paper the more pressure on cylinder. Use this information with your own good judgement. I wouldn’t want to be responsible for damage to any ones property MM