How to fix a Southern Cross Windmill

How to fix a Southern Cross Windmill

(Also known as “how to fix your southern cross windmill” or how to fix a southern cross wind mill or “how a southern cross windmill works”.)

My Windmill broke after many years of good service; and lacking the tools and knowledge to fix it myself (nothing easy to find on Google prior to this post) I procured a pair of professional windmill repairers to do it, asked them some questions and observed the process. So, here’s some second-hand tips on how to fix your own Southern Cross Windmill.

(work in progress October 2009 – pictures coming soon)

Before we start:

Wind mills can be a bit dangerous and fiddly. They’re often damn tall, and may have 30 metres of (heavy) metal pipe hidden from view under the ground; so you’ll need to be careful working on one. If you’re not confident with heights, heavy tools, etc then this probably isn’t the job for you – proceed at your own risk! Things that could go wrong include:

– getting half way up the windmill ladder and suddenly discovering you don’t go well with heights. (Take your phone with you just in case.)
– getting all the way up, then getting knocked off by a suddenly spinning windmill.
– Undoing something at the wrong time and losing bits for ever down the hole.
– Grabbing at something that is rapidly falling into a hole, taking part of you with it!
– Winching up a pipe, hitting the top of the windmill by mistake and breaking something. (Hopefully not winching your ute up the windmill!)

How they normally work.

Well the top bit is kind of obvious. The fan-shaped bit spins around, and some metal rod moves up and down with it. (If these two things don’t happen together you might have a gearbox problem. I didn’t so unfortunately I can’t give you any tips here. There is oil in it ‘tho so it could be worth checking if you’re up there.)

A metal rod then travels down the centre of the pipe that you can see, all the way to the bottom where it joins into the ‘pump’.

The pump is actually quite simple. It’s just a 2 foot long hollow metal cylinder with a plunger in the middle – a bit like you’d find if you took apart an old bike pump. And, just like how cars have cylinders and rings; this plunger-thing has a couple of rings made of either Neoprene or Leather to form a seal. (Those in the know seem to refer to these as ‘buckets’.)

Of course, this design would not quite work without some sort of valve – because you want to lift water ‘up’ the pump but not push it back out again on the down stroke. There are two parts that work together to solve this problem.

At the end of the pump is a non-return valve. It lets water into the pump from the bottom, but (ideally) not back out. So, this means on the upstroke the plunger bit can suck up some more water.

Now, on the downstroke the water can’t get out, so in the centre of the plunger there’s another valve that lets water flow past it on the downward stroke, ready for the next big suck & lift.

In some cases, they may have added a second non return valve to a section of pipe below the pump – presumably as an insurance against one getting stuck open with a bit of grit, and / or to allow any crud sucked up on the up-stroke to have a chance to settle back to the valve and out at a later stage.

So basically you have a reverse bicycle pump, lifting water out rather than pushing air in. The column of water is eventually ejected from the pipe – usually via a T piece, and drained into a tank.

What can go wrong

A few common things that go wrong:

1 – Rust in the pipe causing a leak underground.

Assuming your pipe is metal, it is possible that over time the pipe might rust. If the pipe rusts, then it may develop a leak. You’ll probably hear this as the sound of water being pumped and then immediately drained back down the hole. This would lead to a reduced output, with you only getting water on particularly windy days; if at all.

The rust point is generally near the depth of the water line, and may also be encouraged if the bore casing is metal as well due to electrolysis. (You can now get Poly pipes instead to reduce this risk.)

2 – Buggered Buckets?

Like the piston rings in your car, if the buckets are no longer snug, they’ll have a reduced lifting ability.

3 – Non-return valve stuck.

If your non return valve (or foot valve?) has become stuck open it will let the water back out. I guess you’d have to be unlucky but it can happen.

4 – Siezed pump

If the bore runs dry, it’s possible that the buckets will get hot and sieze. (Apparently more common with neoprene ones.) This then puts significant force on the central rod which might bend it to buggery.

5 – Others.

Other possibilities could include the rod joins rubbing a hole in the pipe, gearbox breakdown, pipe getting a swing up underground, etc.

How to take one apart?

You’re gonna need some fairly heavy duty stuff for this job. Since I’m an IT guy I don’t know all the jargon. You’ll need at least
– a winch or (block and tackle)
– possibly some sort of pulley if you’re winching from ground level.
– a stilson, looks like a wrench, might actually be a wrench
– a pipe grabbing thing. (looks like a motorbike chain on a stick) (Maybe a second stilson / wrench would do – you want to grab two bits of pipe and twist y’see.)
– Some sort of grabby thing so you can attach your winch / lifting thing to your pipe. (They had some special tool for this.) [edit: Advised this might be called a pipe clevis or pipe dog – I can’t find an exact match on the ‘net but you might get some ideas from ]
– A second grabby thing that can hold the weight of the remaining pipe while you unscrew the section above it.
– One or two vice grips. (Google ’em.)
– Other stuff.

The most important thing here is to have some way to lift the rather heavy pipe out of the ground. You might use a winch and a pulley for this purpose.

You’ll also probably need to remove one or two of the side supports so you can get enough room to get the bits of pipe out and have easy access to the bore area.

1 – Secure the fan so it can’t spin. (I guess a rope will do.)
2 – Unbolt the gearbox from the rod.

3 – Unscrew the T-Piece going to your tank. (It’s probably just resting in the tank’s opening so there’s nothing to stop you just unscrewing it and pushing it away.
4 – Unscrew the top section of pipe from the bottom section of pipe. Lift this a couple of feet and you should find the first join on the inner rod. This also unscrews. You do not need to worry about the inner rod falling into the hole unless there’s a major problem down below already (such as a pipe having completely rusted through.)

5 – Unscrew this inner rod using two pipe grabby tools and then remove the upper portion from inside the now suspended bit of pipe.

6 – Now, lower and remove the bit of pipe.
7 – Devise a way to lift the remaining length of pipe.

In my case, they positioned a pulley at the top of the windmill which they threaded a winch through, with a grabby thing on the end.

My suggestion would be to try to have some sort of backup grabby thing down below too just in case the one up top let go.

Proceed to lift the pipe until you get to the next join. Note that the length of pipe might be taller than your windmill, which is a pain as it will mean you’ll need to clamp the pipe and lower your grabby thing. You’ll also need to be careful that the top of the pipe doesn’t hit the top of the windmill; and that if your grabby thing has a remote release rope you’ll want to make sure it doesn’t get caught on something and release when you really don’t want it to.

When you finally get to the next join, you repeat the process by somehow twisting the two pipe segments apart. You might have to do a bit of swearing at them. Applying heat might help them loosen, or just allow you to burn yourself.

Once they are separate, lift the top section a little further so you can now hopefully see the next inner rod join. Unscrew this and like before, remove the rod from the bottom of the suspended pipe. (This might be fiddly so you might need to lift the suspended pipe fairly high to get enough room.

Repeat the process until you finally get to the pump.

You can disassemble the pump by unscrewing the bottom end and then pushing the rod out of it.

If you elect to hone the pump (that is to resurface it) you may need to use new leather buckets as these will expand to fit the new surface. Neoprene ones may not.

Putting it back together?

Umm, I didn’t take it apart. You did 😉

I’ll cover that later. Suffice to say you might need some of that magic plumbers tape that they put on thread. (Probably known as thread tape?) You’ll also need all your fancy lifting gear but in reverse this time. Actually you might be able to cheat with some ropes and a horse knot, but not sure. (A horse knot is where you just wrap a rope around something three times and friction takes care of the rest!)

A possibly useful and interesting site is at


  1. Josh Roberts says:

    Um hello I was just curious as I have bought a property with a comet wind mill on, how much wind is to much & when should I release the tail so as to turn the fan out of the wind. An information will be greatly appreciated. Kind regards josh

  2. john marshall says:

    please draw witch way up or down large and small buckets go

  3. darren says:

    Mate thanks for that i don’t have the money to get some one in so will give it a go now cheers mate

  4. Mick says:

    Question …. how does the pump rod come off the bottom of the gear box …

  5. Dixie Nott says:

    Good summary thanks for your humour and wit. Been offsiding at this job since I was a nipper(female) now faced with the full deal of ‘how to’: but good thing is no bore just a dam.

  6. Bobby PEPPER says:

    I honestly think you have explained on how to fix a windmill pump was very quite clear,I have had a fair bit to do with Station country mills and like a lot of things that need a bit of TLC, every bit of advice is very handy

  7. aaron says:

    Liked what you’ve saidthere is a easy tool to make up ans usr to hang on to the pipes

  8. Brodie says:

    don’t suppose you have any tips on retrieving a column from a bore I was pulling one this morning and the fibreglass column broke in half dropping the bottom half down below the water line I was wondering if there was some sort of clamp or something for grabbing it again and pulling it back up

    • cccmikey says:

      Hi 🙂

      Unfortunately I don’t have any tips for you. I was just an observer when they repaired ours, and have no other experience with windmills.
      I can imagine it’s frustrating! Hopefully you find a solution, or maybe the bore is big enough that it won’t interfere.

      Cheers, Mike.

  9. Sandra ayton says:

    The inertial rod to the pump is hitting the outside we put a capon the top and centre a hole in the top so the rod runs strat.

    • Bill says:

      Any rubbing of two metal surfaces will cause wear.
      You should be able to locate a bearing grade plastic which could be shaped to allow the rid from getting roughed up and worn. Im sure that would help.
      However, I’d recommend that you check the rod and what ever you choose to guide the rod on a regular basis.
      I have seen some rods made of stainless steel.
      There is one set up in the States which I have seen on Youtube (cant remember the Clip’s name, sorry).
      These are of course new and very slick. Stainless steel used to be expensive but now-days, I have found prices make mild steel so much more uneconomic. I suggest seeking a rod made off 316 grade.
      Stainless sliding through industrial grade plastic or nylon should give MANY years of trouble free service.

  10. Peter Allitt says:

    My pump is only providing a small flow of water. I have changed the buckets, dug down to the base of the pump and cannot detect a leak. Is it possible the pump has filled with debris and if so what is the best way of cleaning it out without dissassembling it?

    • Bill says:

      Tis a bit late (now 6 months after your question) but I have just read your Post re not getting much water flow from your Bore.

      Maybe the bore has filled up with too much sediment so actual supply or quantity maybe limited because the Bore has less area for available water.

      One way of cleaning it out (the only way I have heard of) is to get the delivery pipe out of the Bore and replace it temporarily by the following method.

      You will need a large compressor (like, one that takes up a Hire Center’s trailer’s deck)and then lower a hose down to the bottom of the bore.
      It would be best to have a length of pipe VERY SECURELY attached to the end of the hose.
      This is so that it goes down easier and also doesn’t bend when in use.
      I’d double up on methods of securing it to the Hose’s outlet end.
      If it comes off, its probably the last time you will see the pipe.

      Secure the top of the hose also, in some manner, in place at the top of the Bore.

      Then start the compressor and fill the compressors LARGE Air Receiver Tank.

      When the Air Receiver Tank is fully charged, stand well back from the Bore’s surface outlet, pull your Sou-Wester down over your head and neck and reasonably quickly, blow the compressed air down the hose to the bottom of the Bore.

      This will exit all the mud/sediment from the bottom of the pipe and up out of the Bore at ground surface level
      Every thing will get covered with mud but when it all settles down and the only thing that is coming out is a gush of air, it’s done.

      Wait a while (maybe half an hour, or possibly more) and let the bore refill to static level and maybe, do it again.

      It will take a while for the Bore to come back to life, as it used to be, as there will still be sediment in the cracks in the rock fissures that feed the Bore.

      Replace the pipe work again (after checking or replacing the foot valve) and take the compressor back to the Hire crowd.

      The Bore will clear its self over time and in an ideal world, (maybe after a couple of months) do the process again. Then it is more than likely to be a really good supply of water for a longer period of time.

      How successful it is, really depends on the soil and rock the water travels through, as well as the length & condition of the casing pipes.

      Id check the static level before you start any of the above, so as you can measure the success of the effort.

      If you want to screw on an Elbow or a Tee on the top of the Bore with the hose going down vertically, it might be a bit of a mission but you might be able to make a suitable fitting for the air hose to be sealed at the Tee.
      However, it would be best to have a easy curved Tee (one which has an extra large radius) so as the air(carrying the mud)can exit quickly.

      If you want to direct the mud away from the Bore, I’d use a much larger diameter pipe than the air line going from the compressor to the Bore.

      Also, an important comment I need to advise you of, is to secure the Outlet Hose and pipe securely, or it might end up dangerously wiping ya & then drown ya in mud as a final act.

      Best wishes

  11. steve says:

    One major thing, you should never undo any of the windmill supports, it is a triangulated structure and by taking any bits off,in doing so you make the structure very weak and likley to fail and collaps. Also, doing work on a windmill can be very dangerous and should not be attempted unless you have some mechanical competence, understand working at heights, use propper lifting gear and find out a bit about your mill . Dont want anyone to get injured and also loose stuff down the hole.

  12. Kerty says:

    What can bend the centre rod at top of windmill, just had someone fix bottom pump and now rod bent

    • geoff barton says:

      If you are talking about the top center bar that connects to the gear box then it sound like what i did in the past and during attachment of the draw bar the windmill was turning and come together with the bottom attachment point where the top pump rod joins with the wood draw bar mount. As the bore pump is at the bottom it can not go down any more. sliding the U mount between the 50×50 hard wood is done when the wood draw bar is at BDC and the top pump needs to be lifted to meet the mount. if the windmill is turning the mount can miss align on the way down and drive into the pump mount and bend the top bar

  13. charlie says:

    Just put up southern cross winmill 10 IZ-C1 / 151909 just wondering what oil is reqd for gear box and how many litres is reqd to top to correct level thanks.

  14. Gayle says:

    Love your commentary.
    We have a windmill.
    We have had the rusting pipes replaced & the pump reconditioned.
    A couple of g’s later still no water & Yes there is water, the fan thingy turns (when wind blows) & it pumps water but only half way up the paddock some 100 meter, then the water starts coming out the Top of the windmill……?? Had water at 100 m point now no water??? Any ideas?? Thanks

    • Rob says:

      Hi Gayle, we have the same issue. It’s possibly the buckets on the plunger allowing water to escape up the shaft to the top of the windmill. The resistance is less than the resistance of pushing the water through your pipe so it goes out the top instead. We continuously have this problem with our windmill, and when we get it repaired, it was the buckets that needed replacing. They usually last at most 2 years for us.

      • cccmikey says:

        Two years is a very short time – ours goes ten years or more before it has issues. Perhaps you have a lot more foreign bodies in the water which is abrading the buckets?

  15. Jeff says:

    It,s recomended that you use 100 weight hydraulic oil such as Bp Bartran 100 or Shell Tellus 100. The oil level is marked by an arrow under the gearbox where the rotating ladder bolts on.

    • tony says:

      hi Jeff , I have a southern cross mill z series and its leaking oil ? are there oil seals in them and how hard are they to replace , dose the head have to come off or can it be fixed up there in a cherry picker ?

  16. Tim says:

    How does the pump rod come off the bottom of the gear box

  17. Paul says:

    Do the main buckets face upwards and the compensator downwards

  18. james says:

    Thanks for the run down. None of it is going to be easy as all the tools are big, the pieces heavy, and likely rusted. But your explanation is detailed enough. If it all falls on me I’ll have the wife send pictures.

  19. FREDERICK PIKE says:

    Should one treat leather buckets with anything say linseed oil before installation?

Leave a Reply

Your email address will not be published. Required fields are marked *