Sunraysia wheels on Mokes used a unique wheel nut, and it is very important that they be replaced with only the correct nuts.
Part of the problem is they are a closed nut, so they need to have the correct thread depth and stud to tighten on the rim - especially with disc brakes. Sunraysia's also have an unusual 60 degree taper, and can't be swapped for any 'may fit' nuts.
With the right studs and nuts you shouldn't have any trouble - but are you sure that's what you have?
The originals are are getting pretty old now, and some may have been lost over the years or damaged by over tightening.
You really need to have a close look at what you have, and make sure they are up to scratch. Here's a few of the less desirable ones I've had to throw out.......
And this is an original one that has been severley over tightened, used on a damaged rim, or used to hold the spare on where the rim is reversed.
If you have any like this - throw them in the bin where they belong! Or at least put them on the back until they can be replaced.
Missing nuts are often replaced by a standard steel wheel nut - which is better than nothing, but can damage the rim. Check the seat area closely for rounding of the edges. Sides should be straight and clean, with no burring. Damaged seats can easily be repaired with the right tools - but it must be done before fitting new nuts or they will be damaged too! For more information click here.
There are plenty of new nuts out there that will fit a Sunraysia rim - but not all of them fit correctly!
From left to right in the photo above....
Australian Reproduction Nut
Standard UK SN2 Wheel Nut
UK Safety SN5 Wheel Nut
Ebay 3/8 UNF Nut
Australian Reproduction Nuts
Fortunately, reproduction nuts are readily available. They are a bit longer than the originals, but a full set is still cheaper than getting your old ones re-chromed.
Original nut on the left, and reproduction on the right. These nuts are available from all major Australian parts suppliers, and are a good fit as supplied.
UK Mini Wheel Nuts (that may look like they fit)
It is a little known fact that every Mini made in the UK since 1984 has the same 60 degree seat angle on the pressed steel wheels and use a very similar looking wheel nut.
Original on the left, reproduction nut in the centre and Standard UK SN2 nut on the right.
A bit longer again, they are a quality nut with a good finish, quite cheap and often seen on eBay or UK parts sites. However, they are designed for pressed steel wheels and have a much larger base diameter - easily seen here.
Also available is the SN5 'Safety' nut, which has a larger taper designed to have a larger contact area on the steel wheels. Again, these have a larger start to the taper and not suitable for Mokes.
With a Sunraysia wheel either of these nuts would have a very small contact area, and may not even engage the tapered hole. They are not designed for Sunraysia wheels, and should never be used with them.
From time to time there are 3/8 UNF nuts available on ebay that are advertised as suitable for a moke. They are easy to pick, having a larger 19mm or 3/4 hex. Not only do they have the larger start to the taper like the UK nuts, they are also a forged nut which means the thread is not actually in the centre of or square with the taper!
While they are cheap, they simply do not fit Sunraysia rims.
You may also come across reproduction nuts with a groove in the taper - this is not original, and are best avoided.
Don't muck around - buy the proper Australian made reproductions that are correct for your rims.
Whatever nuts you use - the originals or brand new replacements, I can't stress enough the importance of cleaning out the thread to the full depth. If you don't have one, buy a good quality 3/8 UNF bottoming tap like a P&N. Old nuts will be full of crap, and the new ones have been chromed after threading - and are never fully threaded anyway. You should get at least two full turns more out of them just by re-tapping.
This is probably the most important thing you can do - and if you get nothing else out of reading all this, at least buy a tap and clean out your wheel nuts!
Using the correct studs is very important. For drum brakes with one inch spacer drums you should use the 55mm 21A1278 studs. For disc brakes you need to use the shortest 31mm NAM5645 studs.
There is a very easy way to check if your studs and nuts are the right ones. First take the wheel off and have a look at the studs.
This is the difference between the correct disc brake moke stud on the left and a mini stud on the right.
It's fairly obvious that one is longer, but also note the thread on the longer one doesn't reach the face of the flange. Often the longer studs are cut off to the right length, but the nut will still run out of thread before reaching the rim. If you're not sure, look for hacksaw marks on the end like this..
The best check is to screw the nuts on with your fingers - they should almost touch the face of the drive flange. Here is a best case on the left with the correct stud and original nut - and a worst case on the right, reproduction nut on a standard mini stud. There is no way that will hold a wheel on!
If you can't screw the nuts on all the way with your fingers, try running a die nut on the studs.
Can you spot the incorrect stud in this photo? And guess which one snapped when putting the wheel back on!
I know nobody uses a torque wrench when putting the wheels on - but it's the only way to get the right tension on all the nuts. 40- 45 ft/lbs is plenty, and more is definitely not better. Don't let a tyre shop use their rattle gun! A bit of copper grease will help protect against rust and binding, and don't forget to do them up in a diagonal pattern.