[Fot] TR4 Rear Hub Removal

[Jim Prettyleaf]

  When British Leyland dealers were still around one of the dealerships broke the end off of one of the stub axles for my TR-6 when attempting to use the factory approved tool recommended for disassembling the rear hubs.  As you can guess I was rather upset when the Triumph dealer told me that it was my fault for improperly servicing the car and that I would need to pay for the new stub axle.  My opinion was that the dumb-bells in his service department could not decide when to give up and look for a better method, and that the dealer should buy the new axle if I could find a way to take them apart.  This all happened so long ago that I can't recall how I was finally referred to the local expert who knew how to take the TR-6 hubs apart without breaking them; perhaps it was one of my professors at Cal Poly San Luis Obispo who knew this Guru.
   
  According to the local expert the factory tool is not stiff enough, flexes under pressure, and deflects the wheel mounting flange, which then tightens the grip between the flange and the shallow taper on the axle.  The Guru then showed me his homemade fixture which he used to disassembled the undamaged hub, then he machined off the fractured shard of the axle the Triumph dealership broke and used a drift to push out the broken axle.  I was thoroughly impressed and subsequently copied and improved his fixture slightly.
   
  The trick is to hold the wheel mounting flange so that it is flat and cannot deflect when applying the force.  To provide stiffness the top plate of the fixture is made from an 8" square piece of 3/4" thick steel plate and a 2 and 5/8" hole is bored in the middle.  The top plate of the fixture is also drilled to accommodate the four by 4.5 bolt circle of the studs in the flange.  To make sure it cant bend and tighten the taper the top plate is attached to four 3/8 thick by 2 deep rectangular plates that are welded underneath the four edges of the top plate.  After all of the welding is completed the surface that mates to the wheel mounting flange is machined flat using a milling machine.  The top plate does not bend because to do so it would need to stretch four 3/8 thick by 2 deep steel plates.  A steel mandrel that screws onto the threaded end of the stub axle is used to apply the press force.  The mandrel is made with a deep threaded hole so that it completely
 engages and covers all of the threads on the stub axle.  The mandrel also has a shoulder that protrudes past the surface of the wheel mounting flange and applies force directly to the mating shoulder on the axle just past the point where the threads end.
   
  If anyone in the San Francisco Bay Area wants to disassemble TR-4, TR-250 or TR-6 axles just let me know and and we can make arrangements to take your axles and my fixture to a local automotive machine shop that has a 40 ton press.  It is great fun watching the guys that work there cringe when the press is pumped up to 18 tons of force and the small amount of heat is applied to the flange.  Even when the force is minimized by applying a little heat it still makes a very satisfying big bang when the taper lets go.  By the way the mandrel is constructed so that parts cannot fly out of the press and everything is designed so that travel is very limited after the taper releases.
   
  Jim Prettyleaf
  Cupertino , California
  TR-6 Comm # 55432L
   
   

 
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