I need to change the rear drum brake cylinders on a 2006 1.2 Polo. All the car part sites have two options - Cast iron and aluminium. Is there anyway to find out which I have without taking the drum off? 

Thanks.

First Welcome to the Forum.

 

Here is a link to the OEM parts list https://volkswagen.7zap.com/en/rdw/polo+derby+vento-ind/po/2006-461/6/  you will need to find the "PR" code for your car from either the paper sticker in the boot (spare wheel area) or the service book if you have it, other than that you might be able to see the part with the bleed nipple sticking out from the backplate and a scrape with a screwdriver will soon tell if it's alloy or cast iron 

Thanks nige8021,

 

I've tried to decipher the PR codes using one of the online decoders, but still none the wiser. I've attached a photo of the sticker 

OK yeah not showing on there, so the scrape test on the area around the bleed nipple will be the only way to see if it's alloy or cast iron