Air carrier technician reported that while replacing a brake on a CRJ-200 they configured the brake incorrectly.

Narrative

A Brake change on Aircraft X MLG #3 was written up and MLG #4 tire was needed for replacement; so the tire was changed and aircraft was jacked up and ready to start the brake change when I was told to hold off on the brake change so that the plane would be pushed out for another plane to come in for oxygen. After a while the plane came back in and my time to finish the plane before needing to be RTS (Return To Service) was reduced. The brake that was picked needed to have a change in configuration from a right to left axle and was my first time doing a change in configuration of axle for a brake. I had printed out the AMM (Aircraft Maintenance Manual) 32-43-26-04 Removal and Installation of the Brake Unit and had that manual with me at the brake change location and noticed it had a supplement revision; so I printed out the AMM Supp. XX-XXXX and had that with me as well during the brake unit change and forgot to throw out the old manual and only keep the revised one. I was following the Supplement manual and had gotten up to the Installation Procedure 3 Step A then got up to put my headlamp to charge in the meantime I did the configuration change and when I came back I accidentally grabbed the old manual and at the time overlooked the side margins that say 'refer to internal document' and proceeded to use that manual from Installation Procedure 3 Step A (1) to do the configuration change and continued with the AMM 32-43-26-04 which in that manual it says for Installation Step 3 Subtask 32-43-26-960-001 Step A (11) states 'Turn brake unit (4) 180 degrees to a position to fit on the opposite axle.' I had turned the brake as the manual stated and was removing the bleeder; both plugs; and quick disconnect and begun changing their positions as stated in the manual. I then had to use the bathroom; so I left the area and came back and sat in the position before it was 180 degrees turned and continued working so there was where my confusion was with having the bleeder valve installed on the bottom rather than being on the top. I followed through the old manual till the end of the job and when signing off I went back to the workplace to grab the Supplement manual to sign off the work. I had also put the old brake assembly back in the box where the new one came in and closed the lid on it and since I thought I followed the manual correctly and thought I was using the Supplement version of the manual for the brake unit configuration change. I didn't check how the old brake looked with the plugs; bleeder; and quick disconnect were originally positioned; nor did I check the other brake assemblies for reference of how it was supposed to end up looking and didn't ask another mechanic who has done a change in configuration of axle on a brake unit to verify my job was good. I should have thrown out the old manual as soon as I noticed and printed out the revised supplement for the Brake Unit Removal and Installation rather than having it in my work area. I could have looked at the other brake units to verify that was how the brake was supposed to look after doing the change in configuration from a right to left axle and asked one of my fellow coworkers or crew chief to review how the change in configuration was to see if I had done it correctly especially since it was my first ever configuration change on a brake unit.