How to install a Four-Post-Car Hoist

The Installation of a Four- Post Electro- Hydraulic Vehicle Hoist

There are many different makes/brands of vehicle hoists. I have many years of experience installing many of the different models, namely, Stenhoj, Bosal, Kismet, Ravaglioli, Mobi Jack, Bradbury and OMCN, etc. Most of these hoists differ only slightly from each other in the manner in which they have been manufactured. For example: in length, width, load capacity, safety features, etc. Therefore it would be almost impossible to give a detailed account of how each hoist works or is installed. I will however, endeavour to detail the manner in which most of them are installed keeping in mind that certain things will vary from hoist to hoist. The following is a general overview of how a four post hoist might be installed. Figure 1.1 shows a complete four post car vehicle hoist. I will be referring to figure 1.1 below throughout much of this section.

overview-four-post-hoist





1. Power Box
2. Oil Tank/Reservoir
3. Power Column/Post
4. Power Column Cover
5. Pulley cover
6. Power Beam (Cross Beam)
7. Fixed Stop
8. Pulley Cover
9. Auxiliary Column
10. Auxiliary Column Cover
11. Left Hand Platform
12. Right Hand Platform
13. Cross Beam
14. Chock Ramp (Flaps)
15. Centre Beam Cover
16. Side Beam Covers
17. Box Cover

Figure 1.1 A Complete Four Post Vehicle Hoist

1.1 Tools and Materials Required

 Trestles
 Square
 Spirit Level
 Extension Cord
 Creeper
 Hammer Drill with Drill Bits
 Toolbox and Tools
 Plumb Line
 Sleeve Anchors
 Hydraulic Oil (E.g. Castrol AWS Hyspin 32)
 Shims (to level Posts)
 Vehicle Hoist Installation Instruction Manual

1.2 Prepared surface

A vehicle hoist has to be installed on a properly prepared surface. The type of concrete that must be thrown in order for the machine to be safely and securely bolted down would typically consist of cement, sand and stone of which make up MPA… and from a size perspective the section has to be long and wide enough to comfortably accommodate the hoist on. The surface must also be level.

1.3 Installation Process

Before the installation proceeds, sufficient consideration is given regarding working distance from the walls, especially in front of the hoist in cases where it will be used for wheel alignment. If it is new, the hoist is carefully removed from its crating. The parts are carefully laid out in their respective places on the area earmarked for the installation. With the platforms and the cross beams resting on the trestles in a similar manner to the one shown in Figure 1.2below. Usually the electrical point is installed before the actual installation of the hoist. The Auxiliary Column that the Power box is installed on may be erected close to this electrical point

four post car  Hoist on Trestles

Figure 1.2 The Hoist on Trestles

Then follows the process of installing the cables and the pulleys (two double pulleys in the front and two single pulleys at the rear) underneath the static/main platform which is usually situated on the left hand side (figure 1.3 below) of the hoist. They are all pre-checked for wear and tear. This platform contains the pulleys and shafts, the hydraulic cylinder, air hoses (Stenhoj model), etc, while the other platform is void of any of these and is usually able to move either left or right in order to accommodate cars with a wider or narrower wheel base.

vehicle hoist cables being fed through the hoist

Figure 1.3 The lifting cables being fed through the static platform and cross beam.

The cables are then fed through the cross beams and the pulleys (usually four of them) are inserted, one on each end of the same (figure 1.3 below). Great care must be taken to ensure that the cables are fed properly and that they do not overlap, get twisted or are fed through the incorrect channels. It is very important to remember to grease the pulleys and shafts before installing them. The cables are greased after the installation has been completed.

four-post-hoist-pulley-installation

Figure 1.4 The pulleys being installed into the bottom of the static platform and on the end of the cross beams.

Once this is done the cross beams and the platforms are moved together and are squared. This is done by measuring the diagonals Y=Y from the same points on each corner of cross member as shown in (Figure 1.5 below). Before the fixed platform and the two cross beams are tightly bolted together I check that the cross beam’s perpendicular sides are plumb and if not I will shim them by placing body washers above or below the attachment bolt (item 8.3 in figure 1.3 above) in order to make sure that they are. Failure to do this could see the side of the cross beams rubbing against the inside of the pillars thus causing major wear on both of these items, the ratchets (explained below) not locking into the ladders properly and a host of other problems, depending on what brand of hoist I am installing. Adjust if necessary by shimming

squaring the platforms on the hoist

Figure 1.5 The Platforms and Cross Beams of the Hoist Square to Each Other

Items 1, 6 and 11 in figure 1.6 below are

 1 – The eccentric brakes (which come into play if a cables snaps),
 6 – The slides/thrust pads (which prevent distortion)
 11 – and the ratchets which are there for locking the hoist on the ladders,

and are usually all situated on the end of the cross beams. At this point of the installation process, these are all currently exposed and thus are open to be given a thorough inspection before the posts are moved in up against/over them. I check to ensure that they are all lubricated, properly bolted in, and move freely, and are generally in proper working order, etc. The pillars are then moved in up against their slides on the end of the cross beams. The posts are then shimmed using either body washers, or wheel alignment shims to make them level. This is done with the aid of a spirit level. Once levelled, a plumb line is used to insure that they are all square one to another. As the posts are continually being moved during the shimming and squaring process, they are then rechecked to ensure that they are lightly up against the thrust pads before drilling finally takes place and they are bolted down. In order to reduce risk of corrosion on the dyna bolts/sleeve anchors I apply grease to them before knocking them into the ground.

Unfortunately it will not always be possible to have an engineer okay the concrete pad that the hoist twill be installed on. For someone experienced though, It is more than possible to determine by whether the concrete is suitable or not. If in doubt I will sometimes drill a test hole. If for example my drill just sinks into the concrete and/or it is not deep enough, then the owner would be instructed to get a professional to come in and relay the concrete. If my drill struggles through the concrete (in all areas) and if the sleeve anchors pull up nice and tight this is a sure sign that I am installing on a strong, well prepared slab. Obviously I can determine the depth of the concrete by using the measuring instrument on my hammer drill

 The eccentric brake, slides, lock and fittings.

Figure 1.6 The eccentric brake, slides, lock and fittings.

After bolting the post down, the ladders/ratchet rail (Figure 1.7 below), which, with the aid of the locks (item No. 11 in Figure 1.6 above), the hoist rests on for safety and for wheel alignment purpose, etc, are then inserted into each post from the top.

Ladder, Ratchet Rail Shown Inside the Post.

Figure 1.7 Ladder/Ratchet Rail Shown Inside the Post.

The cable ends are then fixed onto the top of the posts (Figure 1.7 below).

Cable Ends Fixed onto the Posts

It is now time to fit the power box onto the main post (usually right front). All of the connections for the limit switches, hydraulic hoses, air piping (if applicable), etc are also done at this central point. The oil reservoir is filled up with the required amount of hydraulic oil. An electrician is then given time to connect power to the hoist and to ensure that he pump/motor is turning in the right direction. In the meantime I can install the Fixed Wheel Stops which prevent car from rolling/driving off the front of the hoist and the Chock Ramps/flaps which assist a car to drive onto the hoist and to prevent it from rolling off the back of it, (figures 1.8 and 1.9 below).

The Fixed Wheel Stops

Figure 1.8 The Fixed Wheel Stops

The Choc Ramps or Flaps

Figure 1.9 The Choc Ramps/Flaps

The installation is nearing completion. The areas around the hoist are cleared. Once the electrician is complete and once I am satisfied that everything is in order and that it is safe to do so, I can now turn the electricity on and push the up button. From here, as hydraulic oil flows into it, the hydraulic cylinder pulls up the slack on the cables, and the hoist is lifted slightly off of the trestles. I will remove these, as they have served their purpose. I will now walk around the hoist to make sure that it is safe. For example, are the cable ends securely in the pillars, have the cables disengaged the spring loaded eccentric locks, is there nothing that could potentially obstruct the hoist form being raised or lowered, etc? I will now lower the hoist to the ground, perform another safety check and then raise it to its highest level while constantly observing it and listening out for any abnormal noises, etc. As the hoist reaches its highest level, I make sure to note that the limit switch, which automatically stops the hoist, performs that its function. Having again made sure that it is safe to do so, I will now lock the hoist on the ladders and enter in underneath it in order to check the following items:

 That the cables are on the pulleys, not twisted and are in their correct place.
 That the cable guides/stays are working properly.
 That the cables are not rubbing against the hydraulic and air hoses, etc.
 That the pulleys and the shafts are securely bolted in.
 That the ratchets are resting securely and safely on the ladders.
 That the cables are securely fastened to the yolk on the end of the hydraulic cylinder
 That there are no leaks on the hydraulic cylinder and hoses.
 That the slack cable limit (if applicable) switch is working properly
 That the hydraulic cylinder is securely fastened to the platform.
 That the overflow pipe from the hydraulic cylinder to the oil reservoir is secure.
 Etc.

After this inspection has been carried out I will lower the hoist to about midway.

My assistant will get onto the hoist and I will then raise it back to the top where it will now be levelled out on the ladders first and then on the cables, again with the use of a sprit level. Once levelled both the ladders and the cables will be locked to ensure that they do not work there way loose and that the hoist does not go out of level prematurely. It will eventually need to be re-levelled once the cables start to stretch.

The hoist will then be lowered once again to the ground the area will be tidied thoroughly and a load test will be carried out on it. Once this is done and the hoist is found to be safe a vehicle will be placed on the hoist and various checks such as locking the hoist at different heights into the ladders, etc will be performed. This will all take place with the operator and manager looking on and taking instruction. The manager and operator will be given strict instruction on how to use the hoist as well as relating to service intervals. I will contact him at these intervals. The hoist can now be certified and used until its next pre planned inspection date. The user manual for the hoist will be given to the manager. This, the safety and load test certificate will be filed and kept by the manager.

/ Vehicle and Truck Hoists

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About the Author

Michael McCabe has 26 years of experience in the maintenance and supply of equipment to the automotive industry. He has approximately one thousand vehicle hoist installations under his belt and is an expert in advising clients on various types of workshop equipment, from vehicle hoists to diagnostics, to electronic wheel service equipment. He has also set up numerous workshops in his time in the automotive industry.

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