Something is prolly struck. Without hearing it myself it may be the rear brakes or the handbrake (common on Astras). Does make the noise as soon as you pull off?

When the vehicle is stationary there is no noise, as soon as the car moves, it starts.

Quote from: knightyit sounds to me like the rear breaks are stuck on...

Bingo!

Had the same thing myself on 2 different cars, both times it was the rear shoes catching because the return springs had gone on one, and on the other the hadbreak cable had snaped (Some cars require the handbreak cable to be used as a return mechanism).  If you want a quick test then jack the back wheels up with the handbreak on and see if you can make them spin.  ALso stick the car in reverse before trying this, dont want the car rolling forward off the jack

Right, I jacked it up a few moments ago while its still light. The rear wheel is fine on the passenger side, but drivers side there is definitely something sticking at a certain point of rotation. The handbrake is working fine as they wouldnt budge with that on.

Brakes sticking then? Is this likely to be the garages fault when the shoes/pads were replaced? Is it servicable by ignorant idiot (i.e me)?

Oh and if I dont sort it out ASAP is my car likely to fly off the road?

If the garage serviced the rear brakes, bring it back to them. Be nice, as its not their fault that an old spring didnt make it through the operation. They shouldnt charge you a copper for it, or if they do, cry uncle and leave.

Otherwise, its easy enough to deal with yourself if you know where all the badgers attach.

Im incompetent, so Ill take it back to the garage  

It should be fine to drive in the meantime, the brakes might overheat a little but thats no bother.

Strangely enough after a good 40 mile round trip earlier it appears to have gone away :? Whats the likelihood of it returning?

How many new badgers did you get installed? The sound could just have been them "getting to know each other", a common enough noise after some brake jobs. Id still get it checked out.

I had both rear shoes replaced, but Id already driven around 300 miles before the problem surfaced.

Theres a good number of parts in a drum brake.  Im guessing broken return spring.

http://auto.howstuffworks.com/drum-brake.htm

Looking at that, if the return spring was broken surely the brakes would be locked on/off or constantly rubbing? As it stands, it all seems to be working fine again.

Surely you value your life enough to have it checked? :shrug:

Quote from: Clockd 0NeLooking at that, if the return spring was broken surely the brakes would be locked on/off or constantly rubbing? As it stands, it all seems to be working fine again.

depends on the design.  Some will back of _just_ enough, or as in your case its possible the edges have worn off the leading edge of the shoes.

Yes I suppose I should get it checked really. At least it isnt going to cost me an arm and a leg. Ill phone the garage in the morning.