Register | Log in
Subscribe

Trail Savvy: High-lift jacks

79
VIEWS

A controversial picture was recently published in SA4x4 showing a reader using a high-lift jack, but not in the correct manner under load. (The jacking handle was at the halfway position, not fully up, while he changed a tyre.) Because of this oversight, we thought the timing right to talk about high-lift jacks and how to use them, as they are a very useful overlanding tool but can also be highly dangerous when used incorrectly.

Because they are relatively low priced and have a myriad of uses, they have become a mainstay in the overlanding community and are standard kit items for militaries and rescue services across the world. A genuine cast iron Hi-Lift (1.5 metre I-beam) will set you back in the region of R2 500, a generic version (1.2-metre I-beam) about half that, at current pricing.

Their simple nature and reliable design have remained largely unchanged since the ‘Automatic Combination Tool’ was invented in 1905 by the Bloomfield Manufacturing Company.

HOW IT WORKS

Using a steel I-beam spine with a series of slots spaced equally along its length, a hand-operated ratchet mechanism uses leverage offered by a long handle to climb up the slots in the beam. As the jacking handle is pressed down, one of two climbing pins in the mechanism unseats, lifts up and slides into the next hole above it. The handle is then lifted up again and the process is repeated. Like walking up a ladder step by step, the mechanism keeps stepping up until the top of the spine or the desired height is reached.

In the same way that the mechanism can climb, when the reversing latch is knocked down (it is pulled up to climb the spine) it can also descend the spine notch by notch to slowly lower the vehicle back down. When lowering, the jack requires constant load, and will release when the load is released, dropping the mechanism the rest of the way down the spine.

USES

While we now mostly refer to the tool as a high-lift jack, the original tool was branded the Hi-Lift Jack. However, it was not always that way: it has been touted as a Handyman’s jack, Sheepherder’s jack, Railroad jack, Farm jack, Jack-all, Unijack − and no doubt many more.

It is certainly a versatile tool, and used for many tasks other than jacking up vehicles. These include debeading rims when fixing a puncture, winching, lifting stumps out of the ground, clamping large items, as a press, for stretching fences, and so on. We have even used a high-lift as a traction aid when stuck in deep mud, and it worked, although this is not something I would recommend.  When used for winching, most high-lift jacks will be capable of pulling up to 3000kg before there is a danger of the climbing pins shearing. This is equivalent to a 6600lb winch, although, of course, it is much slower, and takes much more effort to operate. Typical lift loads are up to 2.7 tons, though ideally one wants to work below that to build in a good safety margin.

SAFETY

When used incorrectly, high-lift jacks can be very dangerous. Bear in mind that lifting your rig on unstable or off-camber conditions is never ideal, even if it is sometimes necessary. Treat the jack as if the vehicle is about to fall off it, and take precautions like always securely chocking the wheels that are not being lifted, and placing a spare under the body when changing a tyre.

Having anyone stand downslope of a muddy hill when you are using the jack as a winch is also an obvious ‘no’; but the most common jacking injuries are cracked knuckles, broken teeth, and even a broken jaw. To prevent this, always keep both hands on the jack handle, and your body/head to the side, whenever the jack is not locked in place in the ‘up position. Releasing the handle when the jack is under load will turn it into an extremely potent bat, with the weight of your vehicle powering it.

USING THE JACK

Because many modified 4x4s have extremely high clearance, their standard jacks are rendered useless, and this is where the high-lift jack becomes essential equipment. On the other hand, most standard 4x4s are not equipped with reinforced bumpers or rock sliders with integrated jacking points, which means that you cannot use a high-lift jack on them without causing damage to their bodywork.

Assuming that your vehicle does have reinforced jacking points, this is the standard procedure:

  1. Put on a pair of gloves, and place the jack on a base plate if the ground is soft. Chock and block the wheels of the vehicle.
  2. Before jacking, make sure that the mechanism (including the Pitman arm bolts, shear pins and springs, and I-beam holes) is lubricated, and free from rust and dirt. Without a load, pull the reversing latch upwards and work the mechanism up a couple of notches to make sure it operates smoothly. Push the latch down again and check that the pins disengage and that the jack slides down freely.
  3. Place the lifting nose of the jack securely into the jacking point.
  4. Yank the reversing latch into the UP position. Begin jacking, pushing the handle all the way down and releasing it all the way to the up-position as the mechanism climbs up the spine one notch at a time. Lifting occurs as you push DOWN. Be sure to listen for the clicking sound as the pins lock in place.
  5. When the load has been raised to the correct position, push the handle upright against the I-beam and, if necessary, keep it in place using the standard spring clip.
  6. When lowering the vehicle, bang the reversing latch into the DOWN position and begin lowering the vehicle. Resistance on the handle will now be in the opposite direction. Remember to keep both hands on the handle at all times, and to keep your head and the spectators clear. If the jack handle slips away from you when you are lowering the load, it may bang up and down violently, so don’t try to regain control of it at this point.
  7. If there are no recovery points on the vehicle (or the vehicle has very long-travel suspension), a ‘Lift Mate’ that hooks onto your vehicle’s wheel may provide a useful lifting point. This accessory cancels out the effect of wheel-droop due to suspension travel, but obviously is useful for recovery purposes only, and not for changing a wheel.

ACCESSORIES

Wheel straps

The Lift Mate uses two hooks connected to a jacking point via sturdy straps. By connecting the two hooks to your wheel rim and jacking from the aforementioned jacking point, you can lift up a wheel without jacking as high as you would from the body, due to suspension droop.

Jack stand

Vital in soft conditions, the jack stand provides a sturdy base and spreads your jack’s load over a wider area when you use it. You can use a block of wood or metal plate to achieve the same effect.

Extender/adapter

A bolt-on round pin adapter to fit alternative round jacking points (often the case on bull bars and rock sliders), and enable the hi-lift to be used further away from the vehicle’s bodywork.

Winch kit

The winch kit should be standard in any decent recovery kit, and includes a short length of Grade 80 chain (rated for overhead lifting work) and a short polyester strap like a tree-trunk protector. The chain can be hooked to the high lift at any point along its length, and the strap is necessary for securing it to a tree or other anchor point.

Hi-Lift repair kit

Be prepared for any eventuality with a basic repair kit. The simple kit includes two climbing pins, two climbing pin springs, two cross pins, a shear bolt and lubricant. Bear in mind that, for fitment, you’ll need a screwdriver − flat or star, depending on your jack.

Even if you regularly lubricate and clean your jack, the zinc-coated climbing pins will eventually wear out with regular use and may begin to corrode, preventing them from moving in their bores, and thus preventing the jack from climbing or lowering. Avoid replacing pins with stainless-steel units as they could have a lower shearing strength.

High lift handle isolator

Another vital piece of kit. This polyurethane isolator slides over the spine and the handle, to keep the handle in place away from the spine of the jack, and to prevent it rattling over rough terrain. Most jacks are supplied with a clip to secure the handle, but this is insufficient when the jack is vehicle-mounted.

Jack bag

When buying a high lift jack, make sure that you get a bag or case for it at the same time, to protect it from dust and rain. Left out in the elements, a jack could well be useless when you need it most.

MAINTENANCE

Like any mechanical device, a high lift jack must be regularly maintained. Unfortunately, most jacks are stored externally because of their size, and left unprotected from the elements. A corroded or dirty mechanism may cause jamming − and severe swearing attacks as the operator unjams the climbing pins at every pump of the handle.

Make sure that the jack is regularly oiled and repainted to avoid rust. The mechanism can be effectively lubricated with a light penetrating oil like WD40/Q20, but avoid using grease, as it attracts dirt. If shifting pins do get jammed, some penetrating oil and a tap with a screwdriver usually frees them.

By Andrew Middleton

Post your comment

To read more articles from this issue please click here. To buy a copy of our magazine, please click here.

Free news, reviews, travel features and more… everything you need to know from the 4x4 and outdoor industry.

preloader