Help frozen brakes!!!!!!

[Tallbut Buxomly]

Ok well in one of those really clever moments i forgot you shouldn't use your handbrake in sub zero temps overnight.
This morning my rear disks are frozen. The car moves as do all 4 wheels but callipers are still pressing against the disk causing a fair bit of friction and drag.

1: how do i unfreeze them safely ?
2: what causes them to freeze ? Ie what aspect... brake fluid, oil ( i would find that hard to believe) or something else?

[edo]

hair dryer.

[Parrot of Doom]

I'd just pour hot water over them. Its only metal.

[Tallbut Buxomly]

Parrot of Doom said:

I'd just pour hot water over them. Its only metal.

Tried this doesnt seem to have worked.

Hair dryer seems a good idea but i am a guy i dont own a hairdryer???

[Risotto]

Tallbut Buxomly said:

callipers are still pressing against the disk causing a fair bit of friction and drag.

Friction causes heat. If the wheels turn then surely driving it will soon free up the pads fully.

[LeoSayer]

Tallbut Buxomly said:

Ok well in one of those really clever moments i forgot you shouldn't use your handbrake in sub zero temps overnight.

I never heard that before, thanks for the tip.

[TooLateForAName]

Depends on the handbrake system. If you have a sheathed cable which has now got iced up then you need to defrost the cable not the caliper. Driving around won't help this situation because the brakes will get hot but that will not unfreeze the cable and release the brakes - it will just stuff them.

[fatboy b]

Could be the cable has frozen up if there's been any water ingress into it, so the caliper may be fine.

ETA - beaten to it.

Edited by fatboy b on Friday 3rd December 10:35

[menguin]

Supersoaker with hot water - always did the trick with my Alfa, the concentrated spray seemed to work wonders (and I must admit I enjoyed the bemused looks of neighbours).

[Tallbut Buxomly]

TLF it is a B6 audi a4 with a normal handbrake system so it may well be that the cable has frozen but i dont think there would be any water ingress but anything is possible.

[John D.]

I suspect it is water that caused them to freeze.

I'd drive off sharpish if you use hot water to release them. Tried to clean my screen after work yesterday with water (washer jets frozen). It froze solid in less than a second, quicker than I could get the wipers on! Scraped off easy enough

[LuS1fer]

It is usually the cable - the rubber bellows tends to perish and water gets pulled in and freezes otherwise boiling water would free it. Though I would say rusty pivots covered in mucky sludge can also freeze and a quick brush and drop of oil on the operating pivot can work wonders.