Put a kettle of boiling water over it ??
Wheel off , punch and hammer in hand and a few gentle taps on the top of the pads should release them - failing that knock f**k out of the caliper with a Monday hammer.
K
Not that it helps in your situation, but in future, spray Atom Mac on the discs, stops corrosion. I use it when the S63 is tucked away for the winter
hot water, or brake cleaner should do it. Be thankful they are steel and not carbon ceramics as it lifts the top layer of the disk and that can get very expensive!
Sincere thanks to all for your suggestions, the collective intelligence of our amazing forum never ceases to amaze me. With your suggestions I successfully released them earlier this evening.
I went to Wickes this afternoon to find a wide diameter punch to reach through the wheel spokes but still transmit a sharp shock from the hammer. The punches were all much too narrow so I bought the heaviest gauge bolster they had, so it had the widest surface area and the greatest length.
I used a combination of hot water and impact, starting gently and progressing in stages to use the minimum amount of heat and minimum amount of force to do the job. First I tried a short piece of wood on the face of the disc and hit it gently with a hammer, building up the force of impact. No joy.
Then I used very hot water from the tap, poured very specifically on the disc around the caliper and pads, but I could only do that on the outside face. I did that twice and tried driving forwards and backwards with my left foot gently on the brakes. Again no joy, so I upped the stakes.
I then added more hot tap water, and placed the blunt flat end of the bolster against the brake disc - through the spokes of the wheel - and struck the the sharp end with the hammer, and tried driving forwards and backwards covering the brakes. Still no joy so I called in the big guns.
I boiled a kettle of water and waited a minute or so, and then poured it down a rubber mat which I used as a funnel to direct the hot water towards the disc near the caliper, the pads and the caliper itself. I then placed the blunt end of the bolster on the face and hit the sharp end harder with the hammer.
I drove it forwards and backwards and it was slightly more willing to move with fewer revs, so I gave it a touch more revs in Drive, trailing the brakes as I did it, and the resistance gradually reduced as I pulled forward. Success, the car was rolling without dragging a wheel.
I took it for a spin around the block in the rain so it’s now dirty again and ironically will need another wash, but at least it’s now driving. I repaired the urge of driving out to a dual carriageway for a few high speed progress stops, but firm braking feels fine from 40-50 mph, so hopefully fine.
Thank you once more. A combination of hot water and metal to metal impact was the the final solution, building up the heat and the force of the impact.