[Fot] TR4 Rear Hub Removal

Fri Mar 9 21:37:14 MST 2007

  Jim,

  I also noticed that the responses were off the topic, and am wondering if others have similar experiences as ours.  I already e-mailed the following response directly to Scott.

  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 Churchill 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.

  Now all you need is a strong enough hydraulic press.  Do not use a 20 ton press, because if no heat is applied to the wheel mounting flange the taper will not separate until roughly 22 tons of force is applied.  When a little bit of heat is applied to the flange with an acetylene torch I have seen flanges separate from the axles with only 18 tons of press force.  Again I do not recommend using a 20 ton press because this is too close to the maximum capacity and things like the press frame and the bridge begin to noticeably bend.

  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 the travel is very limited after the taper releases.

  Jim Prettyleaf
  Cupertino, California
  TR-6 Comm # 55432L

"J.C. Hassall" <jhassall at blacksburg.net> wrote:

  At 11:24 PM 3/8/2007, Scott Janzen wrote:
>Sorry to bomb the list with a non-racing question, but I'm sure many of you
>have a quick answer to this. I just bought a nice original '61 TR4 (#445),
>figured I'd rebuild the brakes before running it, pulled the rear drums and
>found everything soaked with axle lube - need to change the rear seals. The
>manual refers to puller # M86A (doesn't every well equipped TR4 come with one
>of these - hah!) so I'm looking for a source or substitute.
>Also looking for a tire compatible with the car and wire wheels that will
>offer performance without overstressing the stock suspension to replace the
>ancient 165 SR 15s on the car.
Scott

I haven't seen any on-topic responses, so I'll give it a shot. I 
took mine to a shop that rebuilds heavy duty (think dump trucks, etc) 
suspenders, brakes, etc. They had a huge press (100T+). The hubs 
were will supported (very important!). When the axles finally gave 
up heir grip, they let go with one hell of a bang (ok, 2 
bangs). Suffice it to say the special tool wouldn't have come close.

hth

jim
--
Jim Hassall
Blacksburg VA
jhassall at blacksburg.net
'63 TR4 in autox preparation - 90% finished, 90% to go
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