when changing wheel cylinder. do they need to be change in pairs. only one leaking.
No, but if one is leaking now, can the other be far behind? They are cheap, just change them both.
I’d change them both, and check out the front calipers, too.
With the hour + time to get things set up and then put away when finished the time to replace the second cylinder is nearly insignificant and absolutely the ‘good one’ will almost certainly fail before the next oil change so do both. And yes inspect and repair the front as needed and bleed all 4 wheels.
For the uninitiated it’s best to pull both drums and fully repair and reassemble one side leaving the other side to view for reference.
I’ve changed them one at a time before. Usually that is the way I do it. But as mentioned above I often end up changing the other one not too long afterward. But that’s not a big deal if it happens.
I hope you are not actually a Georgia Tech alumni. If you are I won’t be recommending Georgia Tech. to anyone.
You mean b/c Georgia is the peach tree state?