Gman88667733 said:

What I did want to ask, was that when the front was jacked up and the wheel was off, I had to start the engine to rotate the caliper so I could see a bit better. When I started the engine, it all started rotating as if it was moving. The car was in neutral obviously. It was only the one side that was jacked up. Why would this be? Not sure if the opposite side did it too as I had no need to start the engine on that side.

I've never had this happen before? Revving the engine a touch seemed to make it all spin faster too.

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Did you actually have the car in gear while working on the brakes? the car should not be in gear when working on it, use wheel chocks to stop the car moving, The easiest way is, you jack the car in the middle and use axel stands, both wheels are off the ground, so you should only have needed to switch the ignition on to position 1, so the steering lock would be off.
The spinning wheel is normal.

The car was in neutral, of course.
All I did was start the engine to turn the steering wheel.

Gman88667733 said:

The car was in neutral, of course.
All I did was start the engine to turn the steering wheel.

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That's off then the wheels shouldn't move at all-in neutral with the engine running?

Wheels should no move with box in neutral but cold gearbox oil might be enough to transmit enough power to turn the axle. When one wheel is on the ground and the other lifted you can engage any gear. The raised wheel will turn with zero power going to the grounded wheel.

The car was cold.
Hopefully it was just that!
Either way, it drives and stops fine :-D

Hi, Gman, DaveMcT's right, it's absolutely nothing to worry about

When the car's running and in neutral, then all gearbox internals will be moving, with the exception of the output shaft.

Some of the gears themselves will be spinning freely on this output shaft.

Transmission oil is quite viscous, especially when cold, so if one of the driving wheels is up in the air, the turning gears can cause the gearbox output shaft to slowly rotate as there is very little resistance, turning the lifted wheel with it. It can be stopped by hand.

Just in case you're interested, I found these very old American educational films useful for explaining in simple terms how a gearbox and differential work. They're for a rear wheel drive car, but the basics still apply:
https://www.youtube.com/watch?v=JOLtS4VUcvQ
https://www.youtube.com/watch?v=yYAw79386WI