The other day I was driving along and accidentally stuck it in the wrong gear going round a slow corner, the car stalled and I was left rolling along with no power. The biggest impact this had was that the steering went incredibly heavy. I don't just mean a bit heavy, I mean proper, have to hang off the steering wheel to make it turn heavy. Now my current car is quite big but it's *only* 1400kg but I didn't expect it to be so hard.

I used to have a Cavalier that probably weighed the same but had no power steering and I could steer that no problem.

So my question is, why is the steering without power on my current car so hard? Is it because it's configured to be power steered and so I'm moving the servos as well as the steering or something? Is the rack deliberately different in some way? What? I have absolutely no idea how power steering works, clearly.

number of turns lock to lock is usually a lot less with power steering so you have less mechanical advantage, plus as you say you're moving all the power gubbins as well.

Yup, the rack gearing is usually different. That said, maybe you need to get some weights done, while moving (at more than parking pace) even power steering racks are usually fairly easy to move.

I'm looking more and more like a typical roadie at the moment CK, below the waist it's a seething mass of muscle, above it's like a long term inmate at Auschwitz.

That's what I see in the mirror anyway.

yup, the power comes from the hydraulic or electric steering pump which, to keep it simple, is driven by the engine. Therefore if the engine is off/stalled then there's no power to the pump and you do the donkey work!

yes, its cause of the hydraulics.

where as dry steering a car is hard, as the weight of the engine is over non rolling wheels, power steering faliure locks it all up.

the hydraulics stop moving, the pumps stay still, you may as well have no say in it.

dependin on the car, you may not even have a rack.
some cars run by the steering wheel turning a hydraulic pump, that activates linear…. "pistons" i suppose, with an assistance pump inbetween.
the whole system is run under vacum too i think?
so without the vacum pump running, your steering and your brakes are likely to fail.

i know if i move my car without turning it on (rolling to down a slope) i get no steering, have to be aware that the brakes arnt guarenteed to be in a suitable state to use, so use the handbrake (cable link) instead.

then again, i may be talking out my arse.

also on my car (out of interest) if i pump the brake pedal, with the car off, it pumps up and becomes solid, unmovable.

turning to the acc position on the ignition, releases it, at the same time the car whirs (which is the vacum pump preparing the brakes)

I assume your car has hydraulic PAS still?
without the pump running you are really fighting against the hydraulic cylinder that would normally be helping you.

Did you also have to try the brakes without the engine running? Just as scary……

theoretically, its possible to get hydulaic faliure.
I imagine, having your steering lock, and your brakes disappear, at 70+ on the motorway, would be a bit more than "exciting".

touch wood eh

my car has electronic power steering, and the motor failed ealier this year. This gave me intermittent power steering which was terrifying as it would go like the OP described, not fun on a roundabout etc.

Probably also made worse by having a heavy diesel engine hanging right over the wheels.