4-Ton (8,000 LBs) Hydraulic Bottle Jack Heavy Duty Car Lifter with Safety Valve

Discovering that your jack will not reach is a rough way to start a roadside tyre change on a loaded trailer. A bottle jack's extension screw winds out before the ram moves at all, so the saddle can meet a high lifting point without burning hydraulic stroke getting there.

Heat treatment where the stress concentrates

Bottle jacks give up around the base of the ram bore and the saddle mount, because that is where the load path funnels together. This one is heat treated in those critical areas, which alters the structure of the steel so it tolerates repeated load-on, load-off cycles instead of slowly work-hardening and cracking. It is not a feature that photographs well and no one puts it on the box in large type, but it is the difference between a jack that still pumps cleanly after a decade in the boot and one that starts weeping oil after a season of towing.

The bypass, and what it is protecting

Wind the handle past full extension on a jack with no over-travel protection and the ram can push clean out of its bore. The bypass system relieves pressure at the top of the stroke, so the pump stops making height instead of forcing the issue. Together with the safety valve named in the title, that covers the two ways a hand-pumped hydraulic jack normally gets itself into trouble: too much travel and too much pressure. One practical note — the supplier states this 4-ton size is built without a carry handle.

Read the capacity figures carefully

The title gives two numbers, 4 tons and 8,000 lb, and they are not the same rating. Nothing in the supplier's listing says which one is the rated figure, or on what basis it was arrived at. Both appear in the specifications above exactly as supplied. Take the lower of the two as your working limit, load the jack comfortably under it, and keep in mind that a rating describes what a jack will lift — not what it will safely hold while somebody works beneath the vehicle.

Key features

• Extension screw: adjusts to the working height you need before the ram is called on.
• Steel lifting saddle: engineered to hold the load securely rather than slide off the contact point.
• Built-in bypass system: guards against ram over-travel at the top of the stroke.
• Heat-treated critical stress areas: treated where the load path concentrates, which is where these jacks normally fail.
• No carry handle: the supplier specifically notes this size is supplied without one.

Specifications

• Capacity, as listed in the title: 4 tons
• Capacity, second figure in the same title: 8,000 lb — the two do not agree with each other
• Height range: the supplier lists 212 – 407, printed in the source as centimetres; this figure is unverified
• Saddle: steel, with extension screw
• Over-travel protection: built-in bypass system
• Carry handle: not fitted to this size
• Operation: hydraulic, hand pumped

Before you trust it with a vehicle

• This jack lifts only. Get rated axle stands under the chassis and lower the vehicle onto them before any part of you goes underneath it.
• Work on firm, level ground and chock the wheels that stay down.
• Lift only at the jacking points listed in the vehicle's handbook.
• Keep the jack upright. Bottle jacks will not pump properly on a lean, and the seals do not appreciate it.
• The two capacity numbers in this listing disagree. Use the smaller figure.
• The supplier's text references an Australian and New Zealand standard without any supporting certificate. That claim has not been repeated here and should not be relied on.

Within its rating it suits cars, 4WDs, box trailers and caravans. Keep it in the boot with a pair of rated stands and a wheel chock, and a flat tyre on the highway shoulder stops being an ordeal.