your only option is to get a press if you want to be replacing these seals yourself.
by design you cannot just pull the wheel off and pop out the seal because of the axle flange, so therefore your stuck having to buy these units if you do not have the means to remove the axle to get at the seal.
Also if i remember correctly if you do take the axle out there are shims and also the axle nut has to be torqued and they make a special tool to hold the assy just so you can get that torque you need on it. If you don't get it torqued correctly it will come apart.
This is one of the main reasons they made it this way (unserviceable).
Too many failures in the past from field service work because the reassembly was not done correctly.
If you know what you're doing though it can be done.