Removing valve seats from the brake master cylinder

[stovebolt]

To remove the old valve seats from the brake master cylinder, the service manual, page 5-19, says to drill the valve seat with a 13/64" drill bit and tap 1/4 X 20. This size drill and tap seems awfully close to the diameter of the valve seat. Is this an error in the instructions or am I worrying for nothing. I'd appreciate comments from those who have done this job. Thanks, Joe.

[stovebolt]

The mystery is solved. What I thought were the valve seats were actually the bottom of the bores, as someone had previously removed the valve seats, check valves and springs during a rebuild, and did not replace them. I'll simply install a new set. Joe.