JACKING & LIFTING

Lifting and supporting a 4x4 safely requires not just a jack to provide the lifting force but also axle stands, wheel chocks and spreader plates (for soft or uncertain ground conditions).

Jacks

The first piece of equipment most of us will buy for lifting our vehicle will be a Jack. Jacks come in a variety of shapes and sizes ranging from simple ‘scissor’ jacks to hydraulic trolley jacks. Frankly, we’ve yet to see a screw or scissor type jack that we would trust to lift a 4x4 with the exception of very big ex military ones originally used for lifting 10 ton Bedford trucks!

A Scissor Jack is relatively cheap and very effective for smaller vehicles but is not recommended for use on 4x4s

Far better then to stick with a Hydraulic jack since it will be far easier and safer to use and operate if correctly chosen at the time of purchase and correctly inspected and maintained thereafter.

For the home mechanic, hydraulic jacks come in two guises; bottle jacks and trolley jacks.

Automotive bottle jacks are designed to lift vertically in a straight line. Whilst they are excellent at this it is also their prime weakness because they have relatively little sideways (lateral) stability. As you can imagine, when you lift a vehicle the changing angle of the lifting point will always impart some sideways force into the jack. This is especially true if the vehicle shifts or rocks backwards or forwards. Bottle jacks then can be inherently unstable when used on a vehicle and so should only be used for very short periods (eg when changing a wheel) and never when access is required under the vehicle even for positioning axle stands.

Beware too because most bottle jacks only have a relatively small circular end piece, that is in contact with the item being lifted. This end piece must only be applied to a strong flat surface and so it cannot be used under circular axles. Be very careful when jacking that the small end piece doesn’t just push right through the point being lifted. This is especially common on rotten chassis or on the thin, formed steel sections (especially sills) on monocoque vehicles. Some Landrover bottle jacks have been adapted to deal with this and have a ‘U’ type section welded onto the end piece that fits snugly around the axle.

Another shortcoming of bottle jacks is that their design means that they cannot be positioned under lifting points that are closer to the ground than the jack is high. Nor, unlike trolley jacks, can they be moved around whilst carrying a relatively light load, such as when positioning an axle for refitting to a vehicle.

A bottle Jack can lift impressive loads but lacks sideways stability and concentrates the lifting forces into a small end pieceTrolley jacks on the other hand are far more stable than bottle jacks. They use a similar ‘bottle’ type piston and chamber for developing the lifting force but this is applied through a large cup type end piece and the whole assembly sits on steel wheels to allow it to move, thus shifting to accommodate any lateral forces during lifting.

Trolley jacks then are the safest choice for lifting your 4x4 but even these have limitations so here’s a few tips for choosing and using the right trolley jack.

Lifting capacity is all-important. Any jack should have its lifting capacity clearly described on either its original packaging or, more preferably, on the jack itself. All good quality lifting equipment will have a factor of safety built in so that, in reality, the point at which it actually fails is well beyond the lifting capacity marked on it. However, you should never ever deliberately exceed the marked lifting capacity, and given the size, weight and axle articulation of most 4x4’s, always buy a jack whose marked capacity at least equals the vehicle’s gross vehicle weight (not unladen weight). We recommend a lifting capacity of 3-5 tons for the majority of 4x4 vehicles, up to and including, Land Rovers. Some may argue that lesser jacks are adequate, but is it really worth the few pounds that you might save?

Having sorted out the amount of lifting force required, there are a few other factors to consider too. The first will be the footprint of the jack, or, in other words, its length and width. These are important because the bigger they are, the greater the stability they provide. Whilst the majority of trolley jacks have an adequate length (which should be greater than 400mm from front wheels to back wheels), unfortunately, the same cannot be said for their width. For lifting a 4x4, an outer width of at least 250mm is required, measured across the wheels of the jack. This is extremely important, because most jacking accidents occur as a result of the jack tipping over rather than actually failing. While you are checking the wheels of your trolley jack, make sure that they are of solid steel construction with no plastic or rubber "tyre". The front wheels of the jack should be fixed to a solid axle running across the width of the jack, and the wheels themselves should be at least 40mm wide. The rear wheels should be of heavy-duty castor variety, fixed to strong steel brackets welded to the body of the jack itself. These castor wheels should again be of steel construction and set at least as wide apart (preferably wider) than the front wheels

Take a good look at the thickness of the steel used in the construction of the jacks chassis and lifting arm; on a good, strong heavy duty jack, it will be at least 3-5mm thick. The jack handle itself (often supplied in two pieces that bolt together), should at least reach to waist height in the fully upright position. Once assembled, it should be held captive on the jack itself whilst allowing easy operation of the lifting and lowering valve. This valve is tightened by rotating the handle (usually clockwise) until it is tight, prior to pumping it up and down to lift the load (note some jacks can also be pumped up with a foot pedal or compressed air). It is loosened in the opposite direction to lower the jack and load. It is essential that the operation of this valve is smooth and gentle when the jack is fully loaded. There is nothing worse than opening the valve slightly to find that the jack and the vehicle that was resting on it has collapsed suddenly and dramatically to the ground! If you cannot lower your jack and load gently, it should not be used.

Examine too the ‘saddle’ that actually comes into contact with the vehicle being lifted. It should be of a good thickness of steel (3-5mm) and at least 75mm diameter. Some also have rubber pads fitted to prevent scoring or scuffing of the vehicle.

Hydraulic jacks require hydraulic oil for their operation, so check too that you can identify the oil reservoir and that the jack comes with instructions on how to check and, if necessary, top this up (note: only use the manufacturer’s recommended hydraulic oil for topping up the jack).

Hydraulic jacks, whether trolley or bottle, should also be fitted with a built in safety valve to prevent overloading and will also have a bypass system to prevent the lifting piston extending too far.

Having concerned ourselves with the jack’s general construction and ease of operation, we also need to consider how high it can lift, and how low it can lower. Typically, trolley jacks can lower to between 100-150mm, with most coming in around 130mm. Maximum lifting height needs to be at least 400-500mm for use on a 4x4 with its inherently bigger wheels and tyres.

A strong, wide, well designed and well constructed trolley jack.

Lastly a few words about care and maintenance of your jack.

Always store the jack in the fully lowered position since this retracts the lifting piston and prevents it become corroded, damaged or heavily soiled. If the piston surface is anything less than perfect the seals within will almost certainly become worn or damaged and this can lead to dangerous fluid leaks and even catastrophic failure. When you are buying or using a jack, always inspect the extending piston when the jack is fully raised to just to make sure it is in tip-top condition. Any signs of a fluid leak means the jack should not be used under any circumstances. Although spares are available for repairing fluid leaks, we would strongly advise against attempting this as a DIY repair. Either have the jack repaired and tested by the manufacturers service agents or at a professional hydraulic services company (look in Yellow Pages) or for the relatively small cost (compared to paying your own funeral bill) involved go and buy a new jack!

Before using the jack, check the hydraulic fluid level in accordance with the manufacturers instructions and top it up if necessary. If the jack is using a lot of fluid it must be considered faulty and should not be used but rather repaired as above.

Store the jack indoors and if in an unheated garage or shed spray it thoroughly with AC90, WD40 or similar to prevent rusting. Lubricate the jack periodically in accordance with the manufacturers instructions. Typically this involves applying grease to any lubrication nipples and light oil (3 in 1or similar) to the wheels and linkages.

Store the jack on a level surface, as it would be if it were in use. Don’t be tempted to store it on its side or inverted since this can lead to air becoming trapped in the hydraulic circuit within. Before actually using the jack, loosen off the lifting valve with the jack handle and pump it a few times to work the hydraulic oil through the mechanism.

Properly stored, maintained and used a good quality trolley jack will last many years so look after it and it will look after you.

Axle stands

As we have already mentioned, jacks are made for lifting vehicles but they should never ever be relied upon to support the vehicle whilst working on it (with the exception of an emergency wheel change following a puncture, and even then always keep well clear of the underside or wheel arch of the vehicle).

When working on a vehicle after lifting, some other means of support must be used, and one of the most convenient and safest forms of additional support are axle stands. Axle stands are steel supports whose height can be varied to suit the height of whatever is being supported. In use, the vehicle is raised with the jack to the desired height, the axle stands are adjusted to be as close as possible to this height, but still able to be positioned under a suitable supporting point, and the jack is then lowered VERY SLOWLY, such that the weight of the vehicle is transferred to the axle stands. Typically, as befits their name, axle stands are placed under the vehicle’s axles and so are frequently shaped to cradle the curvature of said axle. Axle stands should always be positioned as close to the wheels as the design of the axle allows since this again provides the greatest stability.

Although much simpler in design and construction than trolley jacks, some similar rules to selecting and buying apply. Firstly, the lifting capacity should be at least equal to the gross vehicle weight, but for a 4x4 we recommend selecting axle stands whose capacity is at least double this, in the 3-6 ton range. These larger capacity axle stands have a bigger footprint, are constructed of thicker steel (3-5mm), and, since they are protecting you from the several tons of vehicle above, are well worth the extra few pounds cost.

You will have to shop around for good quality axle stands and avoid at all costs the skinny, tubular stands (secured by a simple pin) that are frequently seen in motor accessory shops. These seldom offer a big enough footprint or sufficient resistance to lateral twisting forces which can occur accidentally when working on a big 4x4. Far better, are the cast column type axle stands, which have wide angled, bases and are fabricated from cast and thick, formed sheet steel (see picture). Cast column axle stands also have a ratcheting height adjustment mechanism, which is far easier and safer than the removable pin of cheaper, tubular stands.

Cast type axle stands are far more rigid and easier to adjust than their tubular counterparts

However, a word of caution to you all, axle stands are perfectly suited to supporting axles but are less than ideal for supporting chassis or other flat areas of the vehicle. This is because they do not spread the load at the supporting point (so thin and rusting chassis can fail), and the relatively low friction metal-to-metal contact between stand and vehicle can lead to slipping if heavy work on the vehicle is being undertaken. For heavy work on a vehicle, where lots of pulling and pushing is required, or where the axles themselves are to be removed, then the vehicle must be supported by something that will both spread the load and accommodate limited, accidental movement. One of the best solutions to this we have found, is to buy new hardwood railway sleepers cut to around 600mm in length (get them cut for you unless you like lots of hard work and blunted saws). Don’t buy old, split softwood sleepers. These sleepers can be stacked either singly or, more preferably, in pairs, such that they support a large section of the chassis and can accommodate accidental movement. An additional advantage of sleepers is that, stacked side by side in pairs, they are excellent at spreading the load on the ground and so can be used where ground conditions are uncertain (more on ground conditions later).

Never ever use rocks, bricks, masonry or concrete blocks of any description to support a vehicle. These materials can crack, topple or break up, especially if accidentally shock-loaded, and have been responsible for many accidents when used as vehicle supports.

Wheel chocks

We have already mentioned the dangers of vehicle movement whilst it is being lifted or supported. Whilst we have covered the precautions that can help deal with this movement, prevention is obviously far better than cure, and so the wheels of the vehicle (those still in contact with the ground), should always be braced with wheel chocks. These prevent the vehicle shifting forwards or backwards (the most likely direction of movement). Engaging handbrake, 4-wheel drive and locking freewheel hubs and differentials should also be done, unless the maintenance work itself requires otherwise. Never put the vehicle into gear, since an inadvertent or forgetful turn of the key could send it lurching off its supports. In fact, for this reason, the vehicle’s battery must always be disconnected whenever it is being lifted or supported for any appreciable length of time (ie anything more than a simple wheel change).

Better wheel chocks are fabricated from steel or thick aluminium and are wedge-shaped so that they can be pushed into close contact with the wheel. For a 4x4, the wheel chock should be at least 100mm high, but remember those big tyres will start to climb even this if something pushes them hard enough.

Spreader plates

Spreader plates are a means of distributing a load over a wider area, and must always be used under jacks or axle stands where ground conditions are uncertain (see more on ground conditions later). They also offer protection to surfaces such as block paving or tarmac, where unsightly scores and scuffs might be undesirable. Spreader plates can be made from thick steel plate, high-density plastics or timber. As previously mentioned, good quality, cut down railway sleepers are excellent at spreading loads, but may be too bulky for certain applications. Reasonably strong spreader plates can be made by using 25mm thick marine-ply sheet, cut into 600mm x 600mm squares. These should preferably be doubled up in use to form a 50mm thick support and may be laid side by side where support is required over a large area, such as under a larger trolley jack. For obvious reasons, try to place axle stands and trolley jacks in the centre of any spreader plate or combination thereof. Note: spreader plates should be viewed as a ‘belt and braces’ precaution where ground conditions are uncertain (old concrete, ageing or non-public highway tarmac, block paving or where shallow drains and cables are suspected), but should never be used as an excuse to work on unprepared surfaces, such as bare soil. Remember, we are talking about planned maintenance and repair of your vehicle, not life or death emergency repairs.

For further information about any aspect of Jacking & Lifting, Please email: info@difflock.com

These and Other Tools are AVAILABLE NOW! from the Difflock 4x4 Multi Store

Back to TOOLS index