How to Build Your Own Rock Sliders in Australia: A 7-Step DIY Guide

Most guides on how to make rock sliders come from America. They use inches, American cars and American rules. This DIY guide is for Australian 4WDs and 4x4 utes like the Hilux, Patrol, LandCruiser, Ranger, Navara, Triton, D-Max and BT-50. Everything is in millimetres, and it explains the Aussie rules too.

In this article+

• Words you'll see in this guide
• Do you need rock sliders?
• What tools do you need?
• What materials do you need?
• Steps 1 to 7
• What are the rules in Australia?
• How long does it take?
• Real builds from Aussie 4WD owners
• Are DIY rock sliders strong enough?

Words you'll see in this guide

Do you need rock sliders?

• Rock sliders protect your sills and the bottom of your doors.
• They attach to the chassis, so they can hold the weight of the car if it drops onto a rock.
• Most side steps can't do that. They're made for climbing in and out.
• If you only drive on bitumen and smooth dirt roads, you probably don't need sliders.
• If you drive rocky tracks, steep rutted hills or tight bush tracks, sliders can save you an expensive repair. A dented sill is hard to fix.

What tools do you need?

What materials do you need?

• Steel tube for the rails. In Australia you buy metric round tube or pipe, often sold by "nominal bore" (NB). Our kits use 32NB mild steel tube: 42.2 mm across the outside, with a 2.6 mm thick wall. Ignore the inch sizes in American guides.
• Short tubes for the infills, the same as the rails.
• Tube for the legs, which go from the slider to the chassis mounts.
• Chassis mount brackets made from thick steel plate. Ours are 5 mm thick.
• High-tensile bolts, nuts and washers. Ours are M12, grade 8.8, 200 mm long, with nyloc nuts that resist shaking loose.
• Gussets, to strengthen the joint between the legs and the mounts.
• End caps, welded over any open tube ends and ground smooth.
• Welding wire and gas (or gasless wire).
• Paint: primer and topcoat, two-pack, or powder coat.

Building from scratch takes more tools and time. Here's how it compares to a pre-cut, weld-together rock slider kit:

Step 1

How do you plan your rock sliders?

Get under your 4WD with a torch before you cut or weld anything.

• Measure the length. Measure along the sill, from the front wheel arch to the back wheel arch. The slider has to fit between the wheels with a little gap at each end.
• Pick a shape. A straight slider (standard) sits close to the body. A kickout sticks out more at the ends and can also be used as a step. On our kits, standard designs are 185 mm wide and kickouts are 237 mm wide.
• Find your mount spots. Look along each chassis rail. Note anything in the way: body mounts, fuel lines, brake lines and exhaust hangers. On a GU Patrol, for example, a body mount sits right where you'd want the front slider mount.

Step 2

How do you lay out the tube?

• Lay every piece out on a flat bench or flat concrete, in the shape of the slider.
• If your tube is already notched, the notches show where each piece goes.
• Sort out the left side and the right side before you start welding.

YouTuber Grouse4x4 built a set for his Patrol and summed it up: "So it's like a jigsaw puzzle."

Step 3

How do you tack rock sliders together?

• Tack the outside frame first: the top rail, the bottom rail and the ends.
• Leave the small infill tubes out for now.
• Measure across both ends. If they match, your frame is square.
• Measure the gap inside the frame and divide it by the number of spaces you want. That tells you where each infill goes, so they're evenly spaced.
• Tack the infills in at the top and bottom.

Here's her whole build:

Step 4

How do you weld out the sliders?

• Check every measurement one more time.
• Weld a little bit at a time. Swap between ends and sides. Heat can bend the frame if you weld one area for too long.
• Clamp the frame to your bench if you can.
• Let it cool down, then look along the rails to check they're straight.

Step 5

How do you make the chassis mounts?

The mounts hold all the weight, so take your time here. There are two main types.

Here's how our universal clamp-on mounts go together:

1. The brackets have long slots (100 mm). Slide the bolt up or down to match the height of your chassis rail.
2. Move the brackets in or out to match how wide the rail is. Then cut the bolt to length.
3. Slide two small plates onto the bolt like washers and weld them to the bracket. This stops the bolt sliding in the slot.
4. Weld in the triangle gussets to make it stronger.

Reubs from Reubs Modification's built two sets like this with his mates. He said the slots let you "clamp them around the chassis and shift the bolt up and down depending on the height of your chassis."

Step 6

How do you set the height and angle of rock sliders?

This is the fun part, where you make them yours.

1. Sit the slider under the car on three jack stands.
2. Line it up with the body line under the doors.
3. Choose how far out you want it. Tucked up close gives more clearance. Further out and flatter makes a handy step.
4. Use your angle finder so both sides match.
5. Measure from the slider to each mount. Cut the legs to length and notch the ends.
6. Tack the legs on, take the slider off, weld everything out, then add the gussets.

Here's his build, with an LN65 Hilux and a GU Patrol done side by side:

Step 7

How do you paint and fit your sliders?

• Weld an end cap over every open tube end, then grind the weld smooth so it's ready for paint. A flap wheel gives the best finish.
• Go over any sharp edges and rough welds with the flap wheel too. Paint sticks better to smooth steel, and sharp edges aren't allowed (see the rules below).
• Bolt them on and tighten everything.
• Check the bolts again after your first trip.

Your paint choices:

Tarah painted hers by hand and recommends powder coat, because painting all the edges is fiddly.

What are the rules for rock sliders in Australia?

How long does it take to build rock sliders?

• It depends on how good you are at welding, and on your car.
• The slider frames go together quite quickly.
• The mounts usually take the longest, because every chassis is a bit different.

"The universal mounts took us a bit longer than we'd originally allocated so give yourself a bit of time to get those set up for your chassis."
Reubs, Reubs Modification's, after building two sets

Are DIY rock sliders strong enough?

Yes, if they're built and mounted well. The strength of DIY rock sliders comes from three things:

• The tube. Use proper steel tube, the same size for the rails, infills and legs.
• Your welds. Full welds all the way around every joint, not just tacks.
• The mounts. How well they hold onto the chassis. This is where most of the load goes.

Take your time on the welds and the mounts, and ask an experienced welder to check your work if you're unsure.

Real builds from Aussie 4WD owners

Here's what each step looks like in real sheds and driveways around the country. These photos come from customers who built a set and sent them in.