Trailer Repairs: Cracked Drawbars, Chassis and Floors

Most trailer damage is welding work: a cracked drawbar, a split chassis rail, a torn ramp or a floor that has rusted through. Caught early, these are usually repaired on the spot. Left alone, a small crack keeps growing every time the trailer bounces over a cattle grid, and a drawbar that lets go on the road is a serious accident. We repair box trailers, car floats, horse floats and stock trailers where they sit, across the Barossa, the Adelaide Hills, the Murraylands and Adelaide.

Where trailers crack

Trailers take a beating that a car never does: overloading, rough farm tracks, corrugated roads and years of sitting in the weather. The damage tends to show up in the same places:

• The drawbar. Where the drawbar meets the front of the chassis, and around the coupling, are the high-stress spots. Look for hairline cracks in the paint, rust weeping from a joint, or a drawbar that has bent down.
• Chassis rails and crossmembers. Cracks start at welds, bolt holes and where rust has thinned the steel, often above the axle.
• Spring hangers and axle mounts. A broken hanger lets the axle shift, and the trailer starts pulling to one side.
• Ramps and tailgates. Hinges wear and crack, and ramp edges get torn up by machinery and hooves.
• Floors. Steel floors rust through where water and manure sit, and timber floors rot at the edges and around the fixings.
• Stock crates and frames. Gates, latches and rails bend when stock push on them.

Check it before the next trip

Give the trailer a proper look with a torch before harvest, a show or a long haul:

1. Clean off the mud so you can see the welds and joints.
2. Look along the drawbar and the front corners of the chassis for cracks, bulges or flaking rust.
3. Lift the drawbar and watch the joints. Any movement between parts that should be solid is a warning.
4. Check the spring hangers, U-bolts and axle mounts on both sides.
5. Walk on the floor and press on any soft spots.
6. Work the ramps, tailgate and crate gates through their full travel.

If you find a crack in the drawbar, do not tow the trailer until it has been looked at. Take a photo and send it to us first.

What we can fix on site

The rig carries the welder, a generator and cutting gear, so most trailer repairs are done in the paddock, the shed or the driveway. Typical jobs:

• Grinding out and welding cracks in drawbars and chassis rails, with plate added where the steel needs more strength.
• Cutting out rusted sections of chassis or crossmember and welding in new steel.
• Repairing or rebuilding ramps and the steel around them.
• Patching or replacing steel floor sections.
• Repairs to stock crates and frames.

We weld steel, aluminium and stainless with MIG, TIG and arc, so alloy trailers, ute trays and toolboxes are covered too. Bigger rebuilds can come back to our Mount Pleasant workshop and go home fixed. See our welding repairs page for the rest of the repair work we do.

Repair, modification or rebuild?

A like-for-like weld repair puts the trailer back the way it was built. Changing the design is a different matter. In South Australia, light trailers (up to 4.5 tonnes ATM) have to meet the Australian Design Rules, and the national guide to building them is Vehicle Standards Bulletin 1 (VSB1). If a job would change the drawbar length, the coupling, the axle position or the rated mass, check with the Department for Infrastructure and Transport or a vehicle engineer whether it needs certification before the work starts. We will tell you if we think your job falls into that category.

Sometimes the honest answer is that a trailer is past repairing. If the chassis is rusted thin along most of its length, or the frame is twisted, new steel throughout can cost more than the trailer is worth. A photo of the whole trailer and close-ups of the damage helps us tell you which side of that line you are on.

What to send us

• The type of trailer (box trailer, float, stock trailer, plant trailer) and roughly how old it is.
• Photos of the damage, plus one of the whole trailer.
• Where the trailer is, and whether it can be moved.
• What you need it for and by when, for example before harvest or a show.

Send it through our contact form, or call Sean for anything urgent. We are based in Mount Pleasant and work across the Barossa, the Adelaide Hills, Murray Bridge and the Murraylands, and Adelaide. If it is a farm gate rather than a trailer, our guide to heavy gate repairs covers that.