How can you change a pressed wheel bearing without a hydraulic press?

Heating a bearing beyond 300 degrees Fahrenheit will likely compromise the bearing by changing the metallurgic structure of the component.

180* is usually adequate, and 250* is a good max to work with. The important thing is to use a rose-bud with a torch (not a regular tip) or an induction heater and heat the component evenly but focus the heat around the key-way if there is one. Remember that the steel expansion rate is about 6 mils/inch dia/100 degree F>

Make sure you have everything in place beforehand, as you will only have a few seconds to install the bearing once it reaches the appropriate temperature. An infrared thermometer will aid greatly in this endeavor.

use the correct tools or a mechanic is ALWAYS the best answer. In regards to the heating and cooling method mentioned before, one poster stated heating the bearings would likely damage them, well in the videos others have mentioned you DO NOT heat the bearings, heat the KNUCKLE that the bearing goes into... your FREEZE the bearings... i have not tried this method nor would i recommend it if you have a set up like the tundra where your knuckle also houses your upper ball joint... but, if you have no other choice research the method carefully.

I used to install steel bushings all the time in machinery all the time. We never heated the receiving bore, just submerged the bushings in liquid nitrogen until the boiling stoops. Usually under a minute. They just slide right in and expand when they come back to normal room temp. That being said, I never tried it with a bearing. MAKE SURE TO USE GLOVES AND NEVER REACH INTO LIQUID NITROGEN TO GET THE BEARING/ bushing! Use a coat hanger or similar to retrieve.

Late answer, but there is no good way to do it yourself. You can heat the knuckle and freeze the bearing overnight as some have mentioned, but it is not ideal and only works sometimes and you need access to a heat source.

Do not use a hammer, you will likely damage the bearing. I do all my own work too, but a pressed bearing is one I pay a shop to do.