To find the correct number you first need to state the car model number. This is quoted on one of the plates under the bonnet. It should commence with 'R' or 'S'. With this part number one should be able to identify the bearing unequivocally.
My parts book (PR 1104, showing all later models) gives the following parts numbers for the bearing : this seems to apply to all models including the smaller (earlier) rear hubs fitted to 845cc vehicles.
— inner : 77 03 090 267. dimensions given as 25 x 47 x 15.
— outer : 77 03 090 266. 20 x 42 x 15.
I would guess that even if you cannot find a Renault part then if you quote these dimensions to a bearing manufacturer they can probably supply one aftermarket.
The parts book also shows a kit containing both bearings, grease cap and bearing outer ring. This is 77 01 460 642. There are umpteen available on eBay from various dodgy locations such as Lithuania, Germany, Great Britain etc.
