How to fix old LEGO train wheels

If you had a LEGO train set in the 80s or 90s, chances are that some of the wheels have come off by now, and they just won’t attach to any of the common LEGO axles.

These are the wheels I mean. They have small metal axles and attach to a thick 4×2 block. In my wheels, all the little axles are long since missing, and all that is left is a wheel with a small hole through it.

Lego train wheels

What I did to fix mine is drill the holes out to fit standard LEGO wheel axles, like in the image below (see ‘the plan’).

The plan

Train wheel plan

You’ll need:

  • A drill press*
  • A 3.2mm drill bit (optional**)
  • A 3.5mm drill bit
  • A 4.5mm drill bit

* You could try this without a drill press, but you won’t get consistent results, and you may get some tight wheels and some loose.

** The 3.2mm drill bit is used to set the depth stop to the perfect depth without trial and error. You can do this with a ruler or something else if you need to.

The steps are:

  1. Enlarge the hole all the way through the wheel with the 3.5mm drill bit
  2. Insert the 4.5mm drill bit and set the depth stop using the 3.2mm drill bit
  3. Drill the hole larger part way through the wheel until the depth stop is reached

The wheels should now snap perfectly onto the axle and spin smoothly without being too tight or too loose.

1. Enlarge hole to 3.5mm

Insert the 3.5mm drill bit in the drill press. Place a block of wood on the platform to ensure you don’t drill into the platform itself. Carefully but tightly hold the LEGO train wheel in place with one hand, and very slowly drill through the centre of the wheel all the way through. Because there is already a hole, the drill centres itself and ensures the hole is perfectly vertical.

Drill 3.5mm hole


  1. Although I wouldn’t normally recommend just holding the work piece between fingers, if you hold it steady and drill slowly you shouldn’t have a problem. The plastic is soft and shouldn’t snag.

2. Set up 4.5mm drill bit depth

Insert the 4.5mm drill bit in the drill press. Now lay the 3.2mm drill bit on the block of wood directly under the inserted bit and lower the drill press until the inserted bit sits on the 3.2mm drill bit. Now set the depth stop so that the drill press will not drill any deeper than that.

Setting the depth stop


  1. A depth of 3.2mm gives the perfect depth for the lego axles to click in place and allow the LEGO train wheel to freely spin. 3.5mm results in a tight wheel and 3mm allows the train wheel to move (too much slop).
  2. If you don’t have a 3.2mm drill bit, use the 3.5mm drill bit from the previous step, and then carefully lower the drill press a tiny bit more before setting the depth stop. It is best to drill the hole too shallow than too deep. You can always drill it a tad deeper later if the wheel is too tight.

3. Drill the 4.5mm hole

Finally, drill the 4.5mm hole in each wheel, lowering the drill press until the depth stop is reached. Remember to drill from the front of the train wheel towards the back!

Drill the larger hole


  1. Make sure you drill from the front of the LEGO train wheel to the back, like in the photo.
  2. Hold the LEGO train wheel securely, and drill slowly. You do NOT want the plastic shavings to snag and pull the train wheel upwards, or you’ll get a hole all the way through the wheel and it will be ruined.
  3. Drill down to the depth stop, not all the way through the wheel!


Hopefully your wheels now snap onto the axles and spin nice and freely! Have fun.

Caravan fun

I haven’t posted in a while – mostly because I’ve been busy on all my other projects – so here is a very quick update of progress with some pictures 🙂

First job was installing the roof.  Carbonised bamboo on either side, with a panel of Lawson Cypress in the middle and remote-controlled 12v LED down lights.

Roof raised ready for work on ceiling
Roof raised ready for work on ceiling
Working on the electrics for the downlights
Working on the electrics for the downlights
New ceiling is in!
New ceiling is in!
Roof raised under carport to work on ceiling
Roof raised under carport to work on ceiling

After a few camping trips, Wife and I were ready for a better bed. We decided to put in a a permanent (almost) full-size double bed to replace the folding table and squabs.  The mattress was made to order by a local bed manufacturer and is only 3cm shorter and the same width as a full double.  We also removed the wardrobe to get extra room for the bed.

The bed folds upwards to allow access to all the storage room underneath.

The kitchen was removed because we never used it and we always cook in the awning.  This allowed room for the bed, too, and I’m making new cabinets to fit the smaller space.

Out with the old table and bed
Out with the old table and bed
Half-way through making the new bed
Half-way through making the new bed

The next job were a few interior modifications. I added a shelf at one end for baskets (clothes etc) that folds up against the wall. We’re removing the wardrobe, so we need extra storage. Another shelf is planned for the other end, but hasn’t been done yet.  Also added a side for one of the beds – our girl was only 1yr old at this stage and we didn’t want her falling out!

Folding shelf - up
Folding shelf – up
Folding shelf - down, with baskets
Folding shelf – down, with baskets
Side on bed for baby
Side on bed for baby

Next up was a new floor to match the ceiling.  The old lino floor looked pretty horrible compared to the ceiling!

Out with the old floor
Out with the old floor
New floor cut to shape
New floor cut to shape
New floor glued down
New floor glued down
New floor finished
New floor finished

Currently I’m building the new cabinets to replace the kitchen that was removed (kept the fridge) and prepping the interior for painting!



Repairing a loose knot

Unfortunately the thicknesser knocked a large knot right out of the timber. The hole is not just unsightly, but may let water and dust enter the caravan from the ceiling space.
Large knot missing

Rather than try to fill the hole with bog, I made a fake knot to fill the hole, and then fixed that in place.  The first step was to cut a small piece of timber from the same plank.  I also removed the loose bark and other material from the hole – note that I didn’t shape the hole in any way – to keep it looking natural.

Cutting the blank

I placed the blank over the hole and roughly marked the shape (oversize!) with a pencil.  Then using a saw, wood file and bastard file the blank was shaped to fit the hole.  The process involved cutting/filing a bit, returning to the hole and marking more pencil, then returning to the vice for more cutting and filing.  Eventually the new fake knot was almost the right size.

Almost the right size

After some final filing the knot fit perfectly into the space left by the loose knot – not too loose and not too tight.  The edges of the knot are not vertical – they are sloped at about 30 degrees so be careful to account for this if you are replicating this process.

Perfect fit

The fact that there is a little space around the edge of the knot doesn’t matter – it makes it look more authentically like a knot 🙂  The final step was to use wood coloured putty to fill all the gaps around it.  On hindsight I should have glued it in place first before using the putty, but I’m hoping the putty will be strong enough to keep the new fake knot in place!

This whole process took maybe 20 minutes.

More middle bit

After tear-out problems preparing the ceiling panels with the thicknesser, I changed the router blades. The difference is remarkable – the finish is now so smooth it almost doesn’t require sanding. I couldn’t be happier.

The three central sections of ceiling panel were run through the thicknesser and honed down to 8mm. I then used the table router to create a sort of shiplap of about 15mm width along the edge of the sections. This allows the sections to overlap when glued instead of simply butting up against each other and triples the area to be glued for a better hold.

The central section is now completely glued up ready for cutting to length and cutting the circular holes for the spotlights.



photo showing the routed overlap. The boards are 8mm thick, the overlap is 4mm x 15mm.

The middle bit

I planned for the ceiling to be carbonised bamboo. This requires 3 sheets of bamboo, with some sort of join between each sheet. After a rethink I’ve decided to split the ceiling and add a central section of Lawson Cypress. The plan is for it to provide some contrast (it is light whereas the bamboo is darker) and tie in nicely with the kitchenette. This way I only need two sheets of the bamboo – one either side of the Lawson – and no panel joiners.

The section of Lawson will be around 700mm x 2000mm. To ensure that it doesn’t end up weighing too much, I am using very thin timber – the finished thickness will be around 8 or 9mm.

I started by selecting a few nice straight 2m lengths of Lawson ex. 100×50, finished. I cut 12mm slices on the table saw off the thinner edge for a size of 44mm x 12mm. I then ran these through my new (second-hand) thicknesser to get them down to 10mm. I was not impressed by the tearout – almost every piece has some tearout damage. I presume its due to the soft wood, but I haven’t checked the blades yet. They may require some honing.

I then glued the finished pieces side by side in three sections around 240mm wide each.

The next step will be to glue the three sections together and finally sand the entire surface to get a nice, smooth finish (hopefully getting rid of all that tearout) and bringing out the grain. I fear there will be a lot of sanding ahead…

Preparing the lid

Once the roof of the caravan (after being removed) was all squared up on the jig, the next part was to prepare the roof before any future work can commence.  The old covering was pulled off, and the foam insulation was removed using a paint scraper.  It was going mouldy in places, and also covered areas that need access to the fibreglass later, so it had to go.  The glue holding the foam to the roof did not lift with the foam, so this will be removed with acetone later.

The fittings, which were very worn, buckled and oxidised, were also removed.  Some needed a spray with CRC to get them moving – but first I carefully measured and recorded their original location so that the replacements will be mounted in the same place!

Total time around 2hrs for this part (so far) without removing the old glue.


Detail of one of the fittings

Removing old insulation in progress

Removing old insulation (in progress).  The water damage and rot is apparent here.

Taking stock

After spending an hour or so taking key measurements of the inside and outside of the caravan and sketching the dimensions out, the next step was to take the roof off and take stock of damage.

The roof has rails along the inside of it’s length on both sides.  The two end walls have runner wheels attached that move inside the rails.  Removing the roof was a case of removing some rubber stoppers from the ends of the rail and letting the roof slide right off the end walls.  Covering the caravan with a tarp is critical at this stage, as it is open to the elements.

The roof removed from the caravan

It then took me a good hour to clean enough of the accumulated grit off the fiberglass (mostly moss and algae) before I could see the sort of shape that the fiberglass was in.  The outer (gelcoat) surface has many small areas of mostly cosmetic damage, but nothing that I can tell that really needs structural repair (see the photos below).  Because of that i’ll be leaving the repair until the final stages of this renovation. as I don’t want to re-damage the gelcoat after putting hours into restoring it!

Rust stain Paint-over botch repair Holes through the gelcoat Nasty botched repair Algae damage Damaged rubber washers

The next step will be making a jig to support the roof as I work on it. Most of the time the roof will need to be upside-down, and without some sort of jig the fiberglass could very easily be structurally damaged.

The plan

Here is the plan for renovating the 1979 Liteweight poptop caravan:

Happening now

(i.e. Wife has approved)

  • Replace the peeling wallpaper ceiling with carbonised bamboo ply.
  • Install 12V recessed lighting (MR11), 230v driver circuit and wireless switches.
  • Attach small 12v winch and hidden pulley system to automate raising/lowering the poptop.
  • Add railing to one of the pop-out beds for 1yr old baby.

Happening soon

(i.e. Wife is thinking about it)

  • Replace hanging cabinetry with bespoke bamboo cabinetry.
  • Add LED strip lighting for reading lights and kitchen illumination.
  • Thicker foam squabs with new coverings.
  • New window coverings to match squabs.

May be happening (or not)

(i.e. Wide doesn’t know yet)

  • Replace damaged linoleum floor with something stylish.
  • Replace convertible seating/bed with permanent double.
  • Add fold-out table to other end of caravan.
  • New kitchen.
  • Re-paint interior.
  • Re-paint exterior.

Opera camper

The Opera camper has got to be my favourite folding caravan design EVER.  Sad to see it’s no longer in production.  Poor timing with the GFC.