Armed with various measuring devices, I checked the dimensions of Range Rover & 90/110 type hubs against Series III. They are not quite the same
dimensions internally, but near enough for the modification I needed to do.
I found out that I had a 90 front axle & a Range Rover rear, no worries, easier in fact, because the internal hub dimension of a 90 seem to be the same
as a Series III
set of freewheeling hubs (with 24 spline internal shaft fitting)
pair of Series III front or rear half shafts with castle nuts & split pins
length of motorcycle fork tubing large enough internal diameter to take the half shafts. (definitely not mild steel here!)
another old pair of freewheeling hubs to cut down (optional)
Access to a lathe, pillar drill & welding equipment is vital. If you don't have these tools, find a friend who has, and is willing to undertake the work.
In my case, welding is always done by my good friend Mr. John (gas axe) Bolt.
A trip to "Dewsbury 4x4 Centre"(01924 455456) came up with a second hand set of "AVM" type freewheeling hubs for a fiver (Thanks to Mick)
Then George at "ATV" in Castleford (01977 603081) gave me load of old broken bits to play with which were from the same type of hub unit.
The half shafts of course came from my donor vehicle (1971 Series III)
90/110 or late model Range Rovers have the CV joint integral with the half shaft so it becomes a much easier job. With old Range Rovers, the CV joint
is a beautifully machined separate unit, so a new outer short half shaft is needed.
Doing The Job
The Half Shafts:
If you have the equipment & skill, it is possible to machine the splines on each end of a piece of the correct type of hard steel, This could prove difficult
in practise, so I opted for the easy way out.
With all raw materials at hand, the first thing to do is cut the half shafts. The overall length of the new shaft was determined at this stage by setting up
the CV joint, stub axle, main hub, freewheeling & hub unit, on the bench in correct order, in order to make sure that there can be no error. You will
notice that a spacer of approximately half an inch thick will be needed between the hub & freewheeling hub, in order that the stub axle does not foul the
latter's inner bearing. Cut the old shafts long enough to allow for the machining of a plug on one & a socket on the other.
A hand hacksaw is no good here, the shafts are made of really hard stuff!
I completely wrote off my bandsaw blade after cutting just one! Maybe the angle grinder is a good idea.
I used John's oxy-acetylene torch. But if using a gas axe, cut the shafts longer than needed & machine them down, because I am a little concerned about
the locally applied heat affecting the steel's hardness/temper rating. When machining them I used carbide tipped tools & high speed.
If you use Series type front half shafts, one of them is tapered so it will have to be machined parallel at this stage. (It is easier to use Series III rear
The geometry of the larger of the two splines allows my 3 jaw chuck to grip the shafts just enough at the spline end for the machining process. If the
chuck doesn't hold them true, machine up a bush from brass or similar soft metal, & tap the shaft into this. It is vitally important before turning them, to
make sure that the shaft runs true in the lathe's chuck. Carefully turn them both down to suit the internal diameter of the motorcycle fork tubing. Make
sure there is no slop, to ensure true running.
Face off the nasty cut end, then centre, drill & ream/bore a half an inch hole for a depth of just over an inch.
On the other end, machine a one inch projection to fit the hole (interference fit).
Make sure, before fitting them together using "Loctite 601" retainer, that the overall length of the complete halfshaft is correct.
Next, machine the shaft outside diameter to fit the internal diameter of the fork tubing. Leave at least a quarter of an inch of half shaft clear before the
spline at each end to allow for the weld.
Assemble the parts & check for true running, between lathe centres. Correct any errors now, before the next operation.
Now, generously weld all the way around the shafts at both ends, ensuring good penetration at all times. Put plenty of weld in, & build it up to allow for
the clean-up. A substantial welding unit is useful here. John Bolt uses a big yellow MIG welder for the job. A small welder should be ok, but turn the wick right up If you can't get the amps, try turning off all unnecessary electrical appliances (except life support machines) in the entire surrounding area
& don't let anyone use your electric cooker 'till you've done welding!
Let the weld cool, then place the complete shortened half shaft in the lathe, if you have one, use a live revolving centre in the lathe's tailstock & clean
up the weld. Not entirely necessary, but it does look better, & makes sure that the shaft doesn't foul the internal diameter of the stub axle.
Repeat the above process for the other one, & now you should have two very neat half shafts.
An important safety precaution .... Drill a hole in the side of the CV end splined part of the half shaft where it fits, up to the CV joint and knock in a
spring pin. leaving a projection to the top of the splines. This is to stop the splined part slipping into the CV joint's internals, if shaft breakage should
occur. If this ever happened, it would be difficult to go around corners, say no more!
Clean & de-grease the Range Rover hubs.
Using epoxy putty or body filler, fill up four of the five original bolt holes in the hub face. (Or leave the original holes alone, should you ever wish to revert back to the fixed hubs at a later date just in case!).
When the filler has set, clean up the jointing face so no filler protrudes.
Bolt the freewheeling unit to the hub, using the remaining bolt hole.
Around the base of this type of freewheeling hub, is a machined groove with an "O" ring in it. You will need a considerably fatter "O" ring to centre the unit on a Range Rover main hub.
90/110's are the same internal diameter as a Series III, so no further action will be needed.
Now, make sure that the freewheeling hub is exactly central on the main hub, which it should be if your "O" ring is doing its job.
Using a drill bit the same size as the hole in the freewheeling hub, deeply centre through onto the face of the Range Rover hub. Check the thread of the bolts used, mine, which is a 90 type I believe, was found to be about M10, but they may vary from model to model. You will need to obtain taps of the size to match your existing bolts.
Remove the freewheeling hub & drill to the same depth as the remaining threaded hole using a bit which is tapping size be careful here, ( ie: the drill must be the size of the bolt diameter minus the threads, to allow the tap to cut threads in the hole's perimeter - as a rough guide, try two imperial drill sizes lower than the clearance drill). Then, with the original clearance drill used for the centre pop, recess the hole slightly, to the same depth as on the original bolt hole. This will guide the tap & ensure true cutting of the thread.
Clear all swarf from the holes at this point.
Now you will need your thread tapping tackle, consisting of taper & plug taps plus a tap wrench would be useful. If you don't have a tap wrench & use a spanner, go easy on the tap, they break surprisingly easily. Also, make sure that the hub you are working with, is on a solid surface or even gently clamped in the vice. To have the lot drop on the floor is sure to break the tap, if not your toes as well......!
The hub is made of high grade cast iron material, so a lubricant for the tap is not needed. But be careful, as a broken tap inside the hole will spoil the work. Back off the tap frequently. When nearly there, remove tap & clear swarf. Go in again to the bottom of the hole with the plug tap.
Now you should have a beautiful 6 bolt Range Rover type hub to take the 6 bolt freewheeling hub unit.
Repeat the above procedure for the other one.
As mentioned earlier, the stub axle is too long to allow bolting up of the freewheeling hub so we need a machined spacer of about half an inch now. This is made from a scrap freewheeling hub base (there are plenty of these about). Just cut it off & clean it up in the lathe, face & bore the spacer for the freewheeling hub "O"ring location, so that the two fit together snugly. Alternatively, a spacer could be machined up from a large piece of mild steel bar, if your lathe is big enough to take it. I found the former plan to be easier, as the projecting "O" ring locating bit for the main hub is already there.
Now we have all the parts. Thoroughly clean them all in solvent to remove any possible swarf contamination. Wheel bearings don’t go round too smoothly or for too long, with metal bits in them! Re-fit the Range Rover hubs & bearings as normal.
Assemble the freewheeling hubs with Series III paper gaskets, screw in the hub end caps, preferably using stainless bolts (much easier to get off later) fill the swivel housings with oil & sit back & admire your handiwork. A well deserved cup of tea is useful at this point.
I think that this modification is well worth the effort for a Series Hybrid Landrover, apart from less drag & noise, if nothing else it saves wear & tear on your front prop shaft universal joints & differential gear when travelling on the road. It looks good too to have technical looking fiddly bits on your front wheels!