Austin Seven Late Model Axle Repairs - Thanks to Ashleigh Ford
In rebuilding a late "D" type differential for a current project, I found I had a collection of damaged axles and hubs. Most of these had the gear end of the axle in excellent condition. With the help of Ashleigh Ford, of the Austin Seven Club of South Australia, we decided not to go the way of normalizing the axle, building up the material and then remachining it etc... Instead, Ashleigh cut about 8 inches off the old axles, turned up new axle ends with the 3 degree taper using ASSAB M709 axle steel suitable for this application.
After measuring the correct overall length, we used the services of a local welder that specializes in axle welding. Ashleigh then cut new parallel keyways. Heat treating is not required after this process. This process has a successful history here on V8 and speedway axles. As for the hubs, we machined the centres out completely and welded in newly-machined inserts with the matching 3 degree taper. Once again we needed to use an outside source to cut the internal keyways in the new hub centres.
All of the hubs had damaged outside threads – this is the thread that the hub puller would normally use. As an alternative to building up this material and cut new threads, I decided to add a ring (about .250" thick and .250" wide) in place of the thread. This was neatly welded on to the hub in a position forward enough to allow a standard puller to be used. This suits a special were hubs may be pulled fairly regularly.
New axles are available for about $250 (Australian). Including the cost of having the keyways cut, this process costs about a third of the new axle cost and is a lot of fun? I must stress that one MUST know the correct steel to use for this process and that a knowledgable person carries out the welding process once again using the correct materials for this process. Otherwise a broken axle IS highly likely!