How does a hydraulic gun turret works

Basically the same principle as the electric powered turret. A hydaulic motor is attached to the turret ring with gears. When hyraulic fluid flows through the pump/gearbox, it turns the gears one way or the other to move the turret. Valves control which wat the fluid flows to control the movement of the turret.
For pros and cons:
Pros: hhydraulics are usually more reliable than electric motors. Also, you draw a huge amount of amps to power an electric motor large enough to turn the turret.
Cons: The vehicle engine has to be running to keep up hydraulic pressure to operate the turret. Hydraulic fluid is very flamable if the vehicle is hit and catches fire, bad news for the crew.

I must disagree with the very flamable part. The fire resistant stuff we have at work won't light no matter how hard we try. They probably didn't have that fire resistant stuff back in the day.

Of coarse I mean that older AFV's didn't have fire resistant stuff

Hydraulic motor attached to the turret ring? - Let's take the M1 Abrams for an example. The Hydraulic pump (which draws non-flammable hydraulic fluid from a 17 gallon reservoir) is attached to the turbine engine through an accessory gearbox. Two lines (feed and return) feed a distribution manifold on the hull floor under the basket. From here fluid is driven into the slipring (below the main gun) and fed at about 1500psi to the traverse gearbox and the elevation mechanisms. The gearboxes are regulated with solenoids which open/close a variety of valves. The gunner or TC input through thier "Cadillac" controls. The turret traverse and elevation are backed up by an accumulator which through the use of inert gas, keeps fluid from bleeding back into the Hydraulic reservoir. When the engine is off, an electrically powered aux pump takes over. The performance is not as good, but it gets the job done. Older tanks feature electric drives and even a combination of manual and electric mechanisms, still older ones are all manual traverse and elevation.

Steve

So which system did most WW II tanks use? Or was it a mixed bag?

In WW2 , I think most were manual , or electric, ( most cases a combination of both).but some tanks like the Panthers , and Tigers , used a " power take off " located beneath the gun , on the turret floor , and driven via , the drive shaft that connected the engine to the transmission. Tanks have manual controls , as a back up , when , all else fails.The Leopard Tanks in the Canadian Army are hydraulic , similar to the M1. There was some trials , in reguards to electric drive , for our Leo's turrets , but there trials didn't get past the prototype stage.
Frank
" PERSEVERANCE"

Call me old fashioned, but I prefer the hydraulic turret to the electric. The electric seems too choppy.

As far as the hydraulic fluid, we haven't used flammable stuff in decades. The old "cherry juice" (red in color) was flammable, but the FRH we use now is not (Flame Resistant Hydraulic). That stuff's been gone since the 70s.

Rob , good feed back! I found electric drive in our Cougar ( a 6 wheeled tankette , with a 76 mm gun, unique to the Canadian Army.Yes, an Army fascinated by a " Wheeled Tank," I.E. the Stryker MGS, what are these people in Ottawa thinking ?!) , choppy , the final lay of the gun , is manual. I like hydraulic, it's smooth and easy to lay on a target with.

Frank
" PERSEVERANCE"

Thanks guys, now I have a better idea. Sorry for the late way overdue gratitude. BTW, if I am correct, by seeing the pics of the older T-34 (1940/42), I guess they used only manual power. Can you imagine how it feels using arm muscles to turn the turret in a crappy two-man turret. Chairman Stalin rally knew how to treat his army tank crew.

didnt some tanks have a combination of all three turret traverse methods