Excavator purchase tips

By: Randolph Covich, Photography by: Randolph Covich


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With the availability of reasonably priced second-hand excavators over the few past years, more rural property owners are opting to purchase their own machines instead of hiring.

Excavator purchase tips
Excavator purchase tips

I recall about ten years ago, someone telling me that the excavator market was saturated with imported gear and he was getting out of the machinery sales game. This may have seemed like the case to him, but since his departure the flow of heavy equipment to our shores seems to have increased.

Quite possibly my friend's main market of excavator sales back then was to contractors and similar users, with many dealers yet to tap into the rural sector market. It seems that these buyers have since been well and truly discovered with many second-hand excavators finding their way to farms around the country.

Often these hand-me-downs are still in very good working order, with the original owners disposing of them to keep up with the latest models available – an all important factor for dedicated contractors wanting to keep the fleet looking professional and eliminate any downtime due to breakdowns. This leaves a good selection of second hand excavators available for a second not-so-busy life.

Things to look out for when buying a used excavator

Excavator size

It seems the most popular excavators for farm work are in the 10 to 12T range, although machines up to 20T are not uncommon. The smaller machines are quite economical to run and can cope with most work a block of land will throw at them. Resale is quite good with these sizes as well, not to mention they are cheaper to shift should a neighbour up the road want a bit of work done.

Engine

Being good practical folk, most farmers will already be familiar with machinery and know what to look for regarding diesel engines. Generally speaking, excavator engines tend to last quite well as they run at near constant revs and will often still be in good running order when everything else on the machine is starting to fall apart. A problem that can occur is diesel bug. This can happen when the machine sits idle for prolonged periods of time. Prevention for this is to always keep the fuel tank topped right up as it eliminates air in the tank and stops the little suckers breeding. Some turbocharged excavators fall foul of quick shut-downs by impatient operator's which is easily rectified with a turbo timer. These are of little help though if the damage has already been done. Pay particular attention if the machine you're looking at has a turbo.

Hydraulic system

The all-important hydraulic system can be a potential money pit if not maintained correctly. Over a period of time the oil seals on the rams will start to deteriorate. Most of the time this will start with the outer dust seal working itself loose and then grit will work its way into the oil seals. If you see any oil dribbling from around the seals, then they will need to be replaced as soon as possible as grit will wreck the seals and contamination will occur to the hydraulic system. You do not want this to happen, as it is an expensive fix if contaminants reach the complicated valve bank. Replacement seals are relatively inexpensive with most suppliers being able to provide generic seals for almost all makes. My suggestion is to remove any leaking rams and get someone who is familiar with this type of work to install the (provided) seals. Finding leaks on older machines can be difficult and can be camouflaged under dirt and scratches, so look extra carefully. It will be easier to spot leaks on gear that has been sandblasted and repainted. If the machine you purchase is in need of a repaint, then I would recommend getting it done. It is not as expensive as you would think and makes it easy to spot any future oil leaks. Be sure to shop around as prices can vary.

Computer system

Excavators are fairly basic pieces of plant however computers form an integral part of the modern models. Like anything electronic, site dust and constant vibrations cause havoc with computers, sensors and the associated wiring. In my opinion computers are fine when machines are near new, but are problematic later in life. Experience tells me few people that can sort a computer problem out and their time can be costly. If you are mechanically-minded and prefer to do most of your repairs, then you may want to consider a machine without one. They are available and there are even new machines available without computers.

Machine turntable

As long as the excavator has been kept well-greased then the turntable should never cause any problems. When the machine is working, if you can see that the upper body of the machine rocks backwards and forwards while the track frame sits firmly on the ground, then there is wear in the turntable and this will need to be attended to. It's a fix that will require outside help. One other thing to look out for in this area is oil leaking from the centre joint. This is located under the machine, right in the centre of the turntable, and will usually spew oil out inside the main body near where the excavator arm joins the body of the machine. The centre joint is fairly easy to remove although it would require climbing up under the machine. My suggestion is to send it away for refurbishment.

Track gear

Because excavators don't do much walking around, the steel shoes generally stay in good order. This can give the false impression that the track gear is in good condition. The main things to look out for is wear of the pins and bushes in the track chain and will be quite easy to spot when looking in the right place. Heavy wear to the pins and bushes will damage the drive sprocket and free turning idler-assembly so replacement of worn chains is very important. Another thing to look for is free movement of all the upper and lower rollers. Seized rollers will quickly cause wear to the track chains but the good thing is that they can be replaced in a fairly straightforward manner. Track chain wear is a prime suspect in dropped tracks so make sure they are kept well maintained. New chains are available, but are costly. It's very important to make sure you're satisfied with the track chains before you buy.

Pins

The pins are what connect all the parts of an excavator arm together. In an ideal world, these should all be nice and tight with copious amounts of grease on them so they move freely. The pins on the bucket are what will always wear our first, so be sure to take a good look at these. If there is any slop in there then these will need to be replaced – probably along with the bushes that hold them in place. This definitely requires outside help and can be more expensive that it looks.

Slop in the bucket (hence a lack of greasing) is a very good indicator of the condition of the excavator and can usually point to lazy maintenance of the machine as a whole.

I can't impress on you enough how important it is to keep an excavator well-greased. If this is carried out regularly then pins and bushes will last a very long time. When using the machine make sure that the two bucket pins are greased every day. The rest of the machine should be ok with a weekly grease – just make sure it is done!

Summary

Obviously, I haven't covered everything a prospective buyer should be looking out for, but have hopefully given a few pointers that have helped me out over the years. If at all possible get someone with a good mechanical knowledge of excavators to have a look at the machine you want to purchase.

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