MG Midget and Sprite Technical 10th Anniversary year: roller release bearings. BBS discussion at MG-Cars.net

MG Midget and Sprite Technical - 10th Anniversary year: roller release bearings.

As this article is for the Spridgeteers (ex Kent midget & Sprite Club area group) quarterly (March edition) news letter I have redacted several names. Image 1: a 948 release bearing. Image 2: the currect 1275 bearing for use on 1275s with a stock clutch. 10th Anniversary of producing Clutch release bearings. Where does all the time go? This month (March 2026) will be ten years of my making roller clutch release bearings. The carbon release bearing as fitted to our A Series engined Sprites and Midgets was a good design proven over many years not just in our cars but others too many to name. Problems arose, however’ about fifteen, or more, years ago when the carbon started to fail early in service: some times less than 200 miles. I certainly was not the first to modify the stock release bearing casting to fit a suitable ball race with suitable faceplate but having been gifted a Myford lathe the opportunity arose for me to make my own. Shaeffler, manufacturers of bearings, confirmed my choice of bearing being suitable for the intended application. I then set-to boring the stock casting, although some castings required boring and lining, before the bearing could be pressed into position. I then had to turn and fit a faceplate. Strangely the castings that caused some of the original complaints re failures proved to be best for modification. In the photo a hole for a roll-pin can be seen. The use of roll-pins on some manufacturers stock appeared to cause cracks in the carbon contributing to its failure. The first recipient of one of my 948 roller release bearings was xxx to be fitted to his Alexander engined Frogeye. Ron sometimes uses a 1098 engine in his car so the 948 was modified so that it could share the 1098 rib-cased gearbox. It was just a matter of fitting an early Morris Minor engine back-plate and using the larger diameter Morris Minor clutch as described in the BMC Special Tuning manual.initially Xxx had one each of my release bearings one 948 and one 1098 but after the conversion the 948 release bearing was redundant so it was transferred to my own 948 Frogeye where it still gives good service, at home and abroad, having covered several thousand miles. Because of the offset, ie the distance between the face and the spigot centre being larger, for the 1098 creating problems for machining to fit a ball-race without risk to life and limb development led to a Mark three type bearing. A Mk2 type, indicated by its red base is shown. The Mk3 type did away with the original casting and a bearing was fitted to a fully machined support with spigots. Xxx (Wiltshire Masc Area Rep) was kind enough to road-test this last configuration which has now proven itself over thousands of miles. Copies have subsequently been fitted to other cars. Sometime visitor to our meetings, Lawrence Slater, whilst on an MG Enthusiast technical site, showed a release bearing that he had made for his 1275 engined car. I felt that I could improve upon it. I chanced upon an actual release bearing that was lightweight at under 250gm, could self centre and, to a degree, run off centre. It was just for me to modify it a little and mount it upon a backplate fitted with spigots. When I, subsequently, showed the result to Lawrence he thought others might want copies as it is a direct replacement for the carbon release bearing without the need for any modifications. Certainly when first shown at a meeting it received enthusiastic comments. Xxx became so enthusiastic that he had his Company’s draughtsman produce workshop drawings of the spigots and backplate, he even produced a laser copy of the backplate to check the dimensions! He then suggested suppliers for production so that, with the aid of a welding jig that I had turned, I was left to weld the CNC’d spigots to the laser cut backplates, assemble, and finish. Thanks must also go to Xxx who converted the original backplate drawing to CAD to suit the demands of the supplier. Demand has been constant from enthusiasts and trade. I now no longer make the release bearings for the 948 & 1098, except perhaps for a friend, as they are labour intense. Robin Human has taken up the baton with these two engine categories: his 948 release bearing being shown. I am glad to have helped him in a small way with his product’s dimensions. Occasionally I experiment with other bearings or make a bespoke item for someone such as shown. As well as Sprites and Midgets my 1275 release bearings are now in use in a couple of A35’s, one a saloon and the other a van, both fitted with 1275 engines and latterly I have supplied two Turner sports car owners whose cars again are fitted with 1275 A-Series

Alan Anstead

This thread was discussed between 02/01/2026 and 05/01/2026

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.