Loaded Pickup on a Two-Post Hoist
A 1.7-tonne light commercial pickup is booked for a clutch replacement. The workshop has a 3.5-tonne two-post hoist. The vehicle carries about 600 kg of tools in the rear load bed and has a nearly full 60-litre fuel tank. The technician positions the rear lift arms under the leaf springs and the front arms under the chassis sill, but the right front pad has lost its rubber block and sits metal-to-metal. The vehicle is lifted about 1.2 m, and a trolley jack remains under the rear axle as a backup. The workshop floor is dry, but the area under the hoist is cluttered with drain pans and an air hose. The technician asks an apprentice to shake the vehicle while he checks the rear spring shackles. State the unsafe practices and the correct lift procedure.
1. Identify the unsafe conditions in this lift and explain why each matters in terms of load path and stability.
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The metal-to-metal pad creates a point load on the sill. A sill is a folded box section, not a solid block; point loading can crush it, reduce friction and allow the vehicle to slide. The rear arms under the leaf springs are also wrong. A leaf spring is designed to flex, and lifting on it can bend it, change the load path as the suspension droops, and leave the vehicle unstable. The trolley jack is an obstruction, not a positive support, and it can be struck or become a pivot. Asking the apprentice to shake the vehicle while someone is underneath introduces a dynamic load that can walk the pads off the lift points. The drain pans and air hose are trip and entanglement hazards.
The combined mass is roughly 2.35 t: 1.7 t kerb, 0.6 t tools and about 0.05 t of fuel. That is below the 3.5 t rating, but total capacity is not the only limit. The rear-biased load means the front arms may be lightly loaded while the rear arms and posts carry more. A two-post hoist must be loaded per its load chart, with the centre of gravity kept between the posts. The safe answer is to stop the lift, remove the load, use the manufacturer's reinforced lift points and correct pads, and recheck stability before anyone works underneath.
2. Describe the pre-lift and lift procedure you would require, including how you would confirm stability before work begins.
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Before lifting, I would check the hoist inspection tag, arm locks, pad condition and the load chart. I would remove the 600 kg of tools to lower the centre of gravity and reduce arm loading. I would position the vehicle so its centre of gravity sits between the posts and use the manufacturer's specified lift points, not the leaf springs or an unreinforced sill. All four pads must be correct and in contact; a missing rubber block must be replaced, not improvised.
I would raise the vehicle about 150 mm and stop. With the vehicle just clear of the ground, I would push and rock it at the bumper, not while anyone is underneath, and check that all pads remain seated, the vehicle is level, no sill is deforming and the arm locks are engaged. Only then would I raise it to 1.2 m, engage the mechanical locks, remove the trolley jack and clear the floor. If any pad loses contact or the vehicle shifts, I would lower it and reposition. No one shakes a vehicle on a hoist while another person is under it. If work requires extra stability, I would use rated stands or a four-post hoist.
3. The vehicle is later found to have a rear-biased centre of gravity. How does this change your lift-point and hoist selection?
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It changes the positioning, not the lift points. I would not move the arms off the manufacturer's reinforced points just to chase the centre of gravity. Instead, I would remove the rear load and reposition the vehicle fore or aft so the centre of gravity is centred between the posts, then check the hoist load chart for the resulting arm loads. A rear-biased vehicle can unload the front arms and overload the rear arms even when the total mass is within rating.
If the centre of gravity cannot be placed within the arm travel, or if the front arms cannot be kept properly loaded, the two-post hoist is the wrong choice. I would use a four-post hoist, a scissor lift rated for the axle loads, or floor stands under the recommended points. I would also keep the working height low until stability is proven. The decision should be based on per-arm loading and the load chart, not simply on 2.35 t being less than 3.5 t.