Hi @Ben7974,
DC04 is an early Dyson upright vacuum which has been out of production for many years. Although we continued to support it far outside of its original 2-year guarantee period, we’re no longer able to supply spare parts or arrange repairs.
You may be able to find any remaining stock of genuine Dyson belts for DC04 from third party retailers, and these will have been manufactured to the right dimensions and with the correct tension to work effectively with the machine, as well as meeting our high quality standards. There aren’t any alternate belts we can recommend - DC01, DC04, DC07 and DC14 models without the brush control feature all share the same belt.
Belts are a consumable part - but if you’re finding that they seem to fail prematurely, it’s worth double checking that the brush bar rotates freely, and is free of debris. If it feels like there’s resistance when rotating the brush bar, the brush bar itself might need replacing.
Sorry I can’t give a definitive answer for you, but hope this insight helps a bit!