Jack Stands (Safety Stands)

Overview

Jack stands, commonly referred to as "safety stands" or "horse stands", are mechanical devices designed to provide rigid, stable support once a vehicle has been jacked up. Their primary function is to take over from hydraulic or mechanical jacks as a solid, long-term load-bearing support, preventing the vehicle from dropping abruptly should the jack suffer hydraulic leaks, mechanical fatigue, or sudden loss of pressure.

In simple terms, the jack is for lifting, while the jack stand is for securing . Under workshop safety regulations, working beneath a vehicle supported solely by a jack is strictly forbidden. Once the car is hoisted to the desired height using a jack, jack stands must be positioned immediately beneath the factory-designated jacking points. The jack is then slowly lowered until the vehicle rests securely on the stands before anyone crawls underneath.

Structure and Working Principle

Jack stands typically feature either a ratchet (pawl) or pin-type height adjustment mechanism. Constructed from welded heavy-duty steel plate or angle bar, they sit on a wide four-leg or flared base to maximise ground contact stability. Operationally, they provide positive mechanical locking—bearing the load entirely via rigid metal-to-metal contact without relying on hydraulic fluid or compressed air, effectively eliminating the risk of pressure bleeding off due to failing seals.

Take ratchet-type stands, for example: the central column is cast with evenly spaced teeth that engage with a spring-loaded pawl on the base collar. When raised to the required height, the pawl automatically slots into the teeth, creating a positive self-locking mechanism that will not slip under vertical load. For added peace of mind, heavy-duty variants often incorporate an auxiliary safety pin for dual-locking protection.

Specifications and Selection

Jack stands are primarily classified by their rated load capacity, typically ranging from 1 tonne, 3 tonnes, and 6 tonnes, up to 30 tonnes for commercial heavy vehicles. When choosing a set, select a rating that is not lower than the vehicle's Gross Vehicle Weight (GVW) based on its kerb weight; a 3-tonne pair is generally sufficient for most passenger sedans, hatchbacks, and SUVs.

Furthermore, stands come in low-profile and high-lift designs. Low-profile versions usually offer a maximum height below 580mm, whereas high-lift models can extend beyond 720mm to cater to taller chassis and different undercarriage clearances. In terms of build, heavy-duty stands are often forged from high-tensile alloy steel or robust 63×5mm angle iron, weighing between 21kg and 24kg for maximum structural rigidity.

Key Usage Points and Safety Prohibitions

Proper Procedure for Use:

1. Park the vehicle on a level, solid surface, engage the handbrake firmly, slot into 'P' (for automatics) or 1st/Reverse gear (for manuals), and chock the diagonally opposite wheels.

2. Jack up the vehicle to the intended working height.

3. Adjust the jack stands to the appropriate height and place them under the vehicle manufacturer's designated jacking points (typically reinforced pinch welds along the sills).

4. Gradually release the jack pressure, allowing the vehicle's weight to settle gently onto the stands.

5. Give the vehicle a firm nudge to verify that the stands are seated securely and there is zero wobble before sliding underneath.

Strictly Prohibited Acts:

• Never use jack stands that show signs of structural deformation, cracked welds, or severe corrosion;

• Never position stands under structurally weak components such as the engine oil sump, gearbox housing, or suspension lower control arms;

• Never place stands on soft, slippery, or sloping surfaces without proper base reinforcement boards;

• Never work underneath a car held up only by a jack—a cardinal rule drummed into every workshop safety course.

Relevance to Vehicle Inspection

While jack stands themselves are not an item inspected during routine vehicle roadworthiness inspections (such as Puspakom), improper lifting practices carry severe indirect consequences. Should a jack give way and drop the vehicle, the resulting structural damage to the undercarriage—such as twisted chassis rails or cracked suspension linkages—will likely be flagged during undercarriage visual or dynamic inspections, leading to an outright inspection failure. Ultimately, deploying jack stands correctly is not just the baseline safeguard for personal safety; it also preserves the vehicle's chassis integrity against catastrophic damage.