Hi, Its real easy, just take off the lid, unscrew the wire clamp. peel off the seal noting the position of the flap. put on the replacement, make sure it is clipped in all the way around, then just replace the wire clamp and the lid. You need thin arms to fit the seal to the bottom of the drum, you have to work from the inside, but it is not a hard job. My machine ps435 is now 30 years old, I have replaced the seal about 3 times. In Melbourne you can get the spares from Stokes in Ringwood. Easy, don't pay a technician.
Philip Mc, February 2010