07-03-2019, 08:31 PM
Brake and Clutch Cleaner works very well. Don't buy it in spray tins, most motor factors will supply it in 5 litre cans. It is quite searching and a lot less unpleasant (and less dangerous!) than thinners or petrol. I have not long done this to the RP's back axle. That looked as if it had been filled with steam engine oil it was so thick. Refilled with SAE140 and ran it for about 100 miles. Just drained it and refilled and the axle is noticeably quieter.