I often get a request for bearing cross reference numbers or alternate suppliers. This is often a knee-jerk reaction to perceived high prices from British parts suppliers (sometimes correct). Other times people may simply want to find a part at a local bearing supply house for immediate procurement (and maybe avoid shipping time and costs). The first thing I will do is to explain how to find bearing cross reference numbers for alternate sources.

Cross references for standard parts are generally easy. First you need one manufacturer's part number (any manufacturer). For a ball bearing or roller bearing the manufacturer's name and part number will be marked on the side of the bearing race. Give this information to any bearing supply house, and they can immediately cross reference it to other manufacturers. With a bit of luck they may have one on the shelf or be able to get it within a few hours or a day from a local warehouse.

If you don't have the part number, but you can get the bearing dimensions from the mating parts, then write down the Inside Diameter, Outside Diameter, and Width. Give these dimensions to a bearing supply house, and they can look up bearings in that size (with multiple manufacturer's part numbers).

If you do not have an original part in hand to know a part number or size, then look in the Service Parts List to find the MG factory part number for the bearing. Do a web search for that number (Google it). This may turn up lots of things not related to bearings, so you may need to narrow the search like this:
"2K7477" +"bearing" +"MG" - - - (This is part number for the rear hub ball bearing).
Look at the search results to find British car parts suppliers. This sometimes yields in-house stock numbers from alternate suppliers. Fairly often it may mention multiple applications for the part, giving more clues where to look for hard to find parts.

Occasionally one of the British parts suppliers may note the manufacturer's part number or dimensions of the bearing. In this case I found County brand bearing number 4208, which turns out to be the standard bearing number. Doing a web search with that number turns up multiple manufacturers like SKF 4208, INA 4208, etc.

There will be hundreds of companies making ball bearings. SKF is a big name that can be cross referenced to other manufacturers. The 4208 bearing is very generic and commonly used in other applications. There are a bunch of Chinese manufactures by now. so the part should be relatively cheap through a local bearing supply house.

There are multiple grades of bearings for slightly different internal clearances, and that can affect the price somewhat. Virtually all rolling element bearings in the MGA have a large safety margin for load capacity. As such, pretty much any available bearing will do the job well, so it is okay to select the cheapest one available (if you have a choice).

There may also be options for open bearings, side shields or side seals (one side or both sides). Seals are exactly what it sounds like, usually sealed on both side (except on special order). These seals keep grease in and dirt out expecting zero maintenance for the normal service life of the bearing. They do not allow for through flow of oil for cooling, could be good for front wheel hub bearings that normally use grease, not so good for rear hub bearings that are normally bathed in oil. Shields look similar to seals but are not sealed. Shields are intended to keep trash out of the bearing while allowing oil to flow in or out in limited amount for cleansing and cooling. These could be okay for a rear hub bearing or gearbox bearings that are normally bathed in oil. Do not use seals or shields where the application depends on oil flowing through the bearing for drainage or to lubricate other parts down stream.

See some bearing cross reference numbers on the following page.