[Fot] TR4 Rear Hub Removal

[Larry Young]

Jim,
That sounds like a useful fixture.  I wish you would put a picture up
somewhere, so I could see what it looks like.

Speaking of hub removal.  Check out the bidding on ebay item
13008552474.  I think I'd rather make a fixture and use a press.
Larry Young

Jim Prettyleaf wrote:

>  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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