AUSTIN THE AUSTIN MOTOR CO. (CANADA) LTD. P.O.BOX 130 STATION "C" HAMILTON, ONTARIO		MORRIS MORRIS MOTORS (CANADA) LTD. P.O. BOX 189 STATION "C" HAMILTON, ONTARIO
NORTH AMERICAN SERVICE BULLETIN NO. 38 VOLUME 4
SUBJECT REAR AXLE HUB OIL SEALS.		DATE 11th December, 1957.

TO ALL DISTRIBUTORS AND DEALERS

Gentlemen,

     When cases of oil leaks are reported from rear axle hubs, the
following procedure should be followed:-

 1.  Ensure that the seal bearing surface on the axle housing is 
     smooth and free of tool chatter marks.

 2.  Check the hub for running true on the axle.  Eccentric hubs
     should be replaced.

 3.  Make sure that the axle breather is in operating condition so
     that no pressure build up at any speed may occur.

 4.  Ensure that only S.A.E.80 or 90 lubricant is used.  Do not over-
     fill the axle but rather fill to about 1/4" below the level of the 
     filler plug.

 5.  Ensure that the spring tension of the oil seal is sufficient.

     In cases where the above procedure has not proved satisfactory, 
     and where continuous complaints have been received:-

 6.  Install an oil seal baffle between the hub bearing and the oil 
     seal.  The part numbers for each baffle applicable to the 
     three series of axles are given below:-

                  "A" Series   ...  Part No. 2A.7293
                  "B" Series   ...  Part No. 1H.7077
                  "C" Series   ...  Part No. 1B.7525

                                    Yours very truly,

                                     Peter Millard,
                                     General Service Manager
                                     North America.
PM:MF

Note that this service bulletin did not come from M.G. Car Company Ltd. It came from Austin/Morris Motors Canada, the Canadian distributor of Austin and Morris cars. The baffle does have a BMC part number on it, but the memo does not refer specifically to MG cars. As far as I know, neither M.G. nor Austin ever issued such a service bulletin for the MGA. I have never seen one of these baffles, not even a picture of one. There is also no mention of it on the internet that I can find, other than this page on my web site. I don't know what the part looks like or where to get one.

Installation of a Speedy-Sleeve (prior article) and a new seal should stop the leak. You might check to assure that the vent on top of the axle housing is not clogged (almost never an issue). If it has oil inside the brake drum it would be an issue with the O-ring and paper gasket at the hub outboard flange. If it leaks down the inboard side of the brake backing plate, then it is getting past the rubber seal. A badly worn wheel bearing or a loose bearing retaining nut could result in a seal leak.

Addendum November 27, 2021:
Here we have a picture of the disassembled rear wheel bearing hub with the baffle (flat shim shape piece next to the bearing), compliments of Peter Baxter in Machico, Madeira, Portugal.

For assembly, put the seal in first, flat side down, open side to run in the oil, and fully seated against the inboard shoulder. Then drop in the baffle, which must be positioned on top of the seal within the same bore, not to extend above the second shoulder. Then install the bearing to be pressed full home against the second shoulder. Keep the assembly horizontal while installing the bearing so the baffle will not fall off center.

If the baffle is misaligned off center to be trapped between the bearing and shoulder, the bearing will not seat properly, and everything is wrong. The hub would be positioned too far inboard, and may drag against the brake backing plate to stop rotation. The outboard rubber O-ring and paper gasket would not seal, and the clamping flanges could be distorted when the nuts are tightened. All bad, and then you have to disassemble it and start over.