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Spare Parts


ECU – 

ECU, or Engine Control Unit Spare Parts is the system which manages the operation of the engine – and maximises power whilst minimising fuel consumption. ECU’s also handle the sensors and let you know if there are any faults or damage with the engine. As these units are a computer, they are delicate and can be damaged by either physical ingress of water or dust, or electrical reasons suchspare parts as voltage spikes.
When an ECU is damaged, generally the entire engine will cease to function, and the ECU needs to be replaced to get the machine up and running again. Your options here are to buy from your local main dealer, or from an overseas stockist of genuine parts. As ECU’s are highly specific for the particular machine you are working on, there are no aftermarket suppliers who can reliably build replacement ECU’s. Feel free to contact us, we are happy to advise on your options on this.

Slew Rings – 

Slew rings were developed for hydraulic excavators and cranes, where it is necessary for the machine body to rotate on the base chassis. Slew rings are a large diameter ring with teeth on the inside rim, which engage with the slew motor. The slew motor is a hydraulic motor which rotates the upper.
As the slew ring is put under high stress loads, and is constantly in use, the teeth can wear and shear, resulting in a malfunctioning part. In this case you may have to look at replacing the slew ring. Reconditioned slew rings can provide you with a very good quality product at a low price, and enable you to get up and running quickly. If you are looking at used, non-refurbished units, you should pick one from a machine with low overall hours, where the slew ring will still have plenty of life left in it. New genuine CAT slew rings can be sourced from your local CAT dealer, whilst aftermarket units are available from many suppliers.
Sigma are glad to help advise you on your options on this, and help you with the best solution to your issue.


Hydraulic Motors – 

Motors are part of the hydraulic system on excavators, wheel loaders, crusher and screens, and other construction equipment. They use the pressure and flow from the pump, and convert the energy into rotary force, and are used for driving wheels, conveyor belts, and slew rings.
Replacement hydraulic motors are available from many suppliers, however at Sigma we recommend you look at sourcing the same pump that was fitted onto your machine when new. This will ensure that the motor will fit straight onto the machine when it arrives, and also ensure the longest serviceable life.
We are glad to discuss options on repairing or replacing your damaged motor, please let us know your situation and we will advise!


Hydraulic Pump – 

Pumps are driven by the engine, and produce the pressure needed for operating construction machinery. Because they are working under constant pressure, pumps wear and can break or require rebuilding. This is common especially with older machines which have done high hours. As a guide, pumps often require repair/rebuilt every 15-20,000 hours, although heavier applications may wear the pump sooner, whilst lighter applications may delay pump failure.
Sigma can advise best options to repair damaged hydraulic pump, we have options to help you with finding used hydraulic pumps. If rebuilding your pump is a better option, we have bought rebuild kits to make pumps work again. We also work on fast shipping times to help your machine get producing again quickly.

Hydraulic Ram – 

Hydraulic rams are an integral part of hydraulic systems on construction equipment. Rams often get damaged, and the chromed rod can get pitted or corroded with dust. Options to repair a damaged ram on a machine are either to rechrome the rod, or replace the entire cylinder. This may be a preferred option either where there is not an option to rechrome the cylinder rod, or where the ram has sustained other damage. This is possible, as rams are exposed on excavator booms and are liable to damage. Bucket cylinders, dipper cylinders and boom cylinders are especially prone to damage.
Sigma can advise on the best option for hydraulic cylinders, we have experience in rechroming rams and also we have fitted new cylinders onto machines. Hydraulic cylinders are built by manufacturers, like Caterpillar or Komatsu, and also aftermarket suppliers.

Hydraulic Ram Seal Kit –

Pressure seals on hydraulic rams, pumps and motors often develop leaks due to the harsh conditions and high pressures involved. It is regularly required to reseal a hydraulic ram or other component due to hydraulic oil leakage. If the leak was not treated, the level of hydraulic oil in the machine would gradually drop as oil leaked, and potentially cause damage to other components on the machine.
The good news is that replacement seal kits for construction machinery are relatively cheap and very high quality. We can vouch for both OEM and aftermarket seal kits with long operational lives.
If the chrome on the rod is cracked, damaged or corroded, the oil will leak, and this will not be rectified by changing the ram seal. In this case, the rod will need rechroming, which is where the cylinder is dismantled and the rod is resurfaced in chrome to allow the seal to work. In extreme cases, you may need to replace either the rod or the entire cylinder. View our CAT Seal Kits here.


Hydraulic Hoses


Sigma PlantFinder supply wearing parts such as a full range of European hydraulic hoses, for all types of machinery and heavy equipment, together with fittings, couplings and ferrules. Our pipe-making machinery is built in Britain, for robust and simple operation. This enables you to take complete control of your on-site hydraulic repairs, whilst minimising cost and only using the pipe you need.wearing parts

Manufacturing hydraulic hoses is relatively simple, given the right equipment and proper training. The pipe must be cut to length, to avoid looping or bending too tightly, both of which can reduce the life of the hose. The cut end is then cleaned, or skived, to allow the pipe fitting to sit perfectly. Once this is done, the correct fitting is selected and crimped onto the end of the pipe using a phydraulic hosesipe crimper or pipe swaging machine.

We provide full training, both onsite and video-based, to ensure your staff have the highest proficiency in manufacturing hose. And we can deliver boxes, single pallets or full containers of hoses and pipe fittings in our monthly container service to major African ports. For more information on the wearing parts we can supply for your machinery, please contact us today.

When buying a machine or parts from us, if you need, we can send out a fully qualified engineer to set up the machine or fit the part. They will be fully certified for this job and will travel to your jobsite.


Sigma can supply you with a wide range of Piling Rig Spare Parts. Whatever part you need for your Piling Rig Parts, please contact us and we can source these for you tailored on your requirements.

Kelly Bars –

Kelly bars are used in rotary piling rigs, to allow the rig to drill deep foundations. Kelly bars are either telescopic (used on self-propelled rigs, like Bauer rotary piling rigs) or fixed, which are used on crane mounted rigs like the Soilmec RT-3.

Telescopic Kelly bars are either friction or interlocking. Interlocking units are generally used on higher-torque or larger diameter piling operations.
If you are looking for used Kelly bars to replace a damaged or broken Kelly bar, Sigma recommend you look at a new option. Sigma can supply new, European and Italian-built Kelly bars which are interchangeable with Bauer Kelly bars, Soilmec Kelly bars and Casagrande Kelly bars. These have the added advantage of being similar price to a used Kelly bar, but in new/unused condition.

piling rig parts

Pile Breakers –

Due to the diversity of foundation techniques worldwide, the range of pilebreakers have increased considerably. The latest technology makes it possible to break prefab piles (square, hexagonal, octagonal and round) and cast-in-situ piles (round). The entire process is 10 times faster than conventional breaking methods and done in a controlled and safe way.


We can provide a range of attachments and wearing parts for piling and drilling rigs. Soilmec Ltd provides a complete drilling tools range which includes both standard drilling tools and customized drilling tools. Making sure your machinery is in top working order is vital because if it isn’t then you will not get the full capacity and capabilities from the machine. Some more wearing parts and attachments we can provide include; boring buckets, core barrels and augers.



We are the industry leaders in exporting replacement parts and at making sure they reach you in a record time.

Our Quarry Parts include:
Quarry screen mechanism parts, screen mesh and rubber conveyors belts.
Jaw crusher jawstocks, jaw plates, cheek plates, flywheels, mainframes and pitmans as well as eccentric shafts, labyrinths, spacers and end covers for most popular brands.
Cone crusher mainshafts, head cones, socket liners and eccentric bushings as well as gasgets, filters and seals. All our products are manufactured in the UK and are compatible with popular brands.

Crusher Wearing Parts –

Crushers are quarry machines, designed to handle high stress loads and abrasive products, and work in demanding and rough environments. Crushers get some of the hardest wear of any construction machines, and are designed with removable wear parts that can be replaced with quarry wearing parts as they wear down.

Examples of these quarry parts are as follows:

Jaw Crushers – the main wearing parts on jaw crushers are the jaw plates and cheek plates. These are often reversible, and have wearing surfaces on both sides, so you get double the wear out of each plate. Other items such as rubber conveyors, rollers and conveyor head drums and drive motors often also require replacement, as they handle the stress and wear of carrying the crushed stone.

Cone Crushers – on a cone crusher the concave and mantle are designed to take the wear, as they crush the rock between the two cones. A well-designed cone set will maintain its shape as it wears, and still provide good crushing performance. Cones are specifically designed for a particular model, please let us know what machine your wearing parts are for.

Impact Crushers – as an impact crusher performs as much product size reduction as a jaw/cone combination, the wearing parts on impact crushers can wear very fast. As a result, it is recommended not to use an impact crusher on very hard or abrasive rock, such as granite or basalt. This will result in high costs for wearing parts and downtime, whilst a jaw/cone crushing line will result in a lower cost per tonne. Impact crushers have wear bars, or impact bars, on the central axle, and wear plates round the outside of the crushing chamber. All of these are relatively easy to replace.

Sigma are glad to advise on the best option for your wear parts, and choose the best type of wear plate – whether it is 14% manganese, 18% manganese, or ceramic units.

quarry parts

Screen Mesh –

Quarry screens are designed to separate out different sizes of aggregate, and are built to withstand heavy work loads and abrasive products. Depending on the size of aggregate you require, you may need different sizes of screen mesh to produce the correct size grading. Widely-used sizes are 40mm screen mesh, 20mm screen mesh, 10mm screen mesh, 5mm screen mesh and 2mm screen mesh.
Sigma can help you with woven screen mesh, piano wire mesh, welded mesh, fingers and punch plate. Whatever your application we can support your screen mesh requirements.
Screen mesh decks are fitted into the screen box with long tensioners and tension bolts, we are happy to quote on these if they are required.

When a screen mesh wears it often develops holes, which impacts the accuracy of screening and results in contaminated stockpiles and inaccurate screening. Screen meshes are cheap and easy to replace. Sigma can supply mesh and other quarry parts from the OEM supplier of world-class mobile screening manufacturers.

Conveyor Belts – 

Sigma can provide world-class conveyor belts from the supplier of global brands of mobile crushing and screening equipment. Smooth or chevron belts are both used in screeners, and we can supply replacement conveyor belts for screens such as the Finlay 694, Powerscreen Chieftain 2100, Sandvik QA450 and QA451. If you have damaged conveyor belts which require patching, we can supply conveyor clips which allow pieces of rubber to be patched into the belt.
Sigma can also supply prejoined conveyor belts, and also the tools and equipment required to make endless conveyor belts, where the rubber is glued on a chamfer so no join is visible.
If you require conveyor belts, we can also supply conveyor rollers, conveyor side rollers, return rollers, and conveyor head and tail drum rollers for use in mobile screeners. All our replacement parts are high quality as used by OE manufacturers.


Rock Drill Parts – 

Rock Drills, also called blasting rigs or blasthole drill rigs, are small and manoeuvrable drill rigs designed to drill small diameter (up to 60mm) holes for blasting. Generally less than 20m deep, these holes are arranged in a pattern that ensures the right size rock for crushing is produced from the quarry blast face.
Rock drills are subject to high wear, and drifters must be refurbished every 1500-2000 drilling hours. Sigma can support your drilling operation with replacement drilling rods and drilling teeth or button bits, with high quality replacement parts.
We usually airfreight parts to you, resulting in a 3-5 day shipping time, to keep your equipment producing and reduce downtime as much as possible.

Rubber conveyor belts are built from high-performance rubber composite, designed to handle both the surface wear from carrying crushed stone, and the internal stress imposed by the conveyor drive system. Good quality conveyor belting is essential to keeping your quarry operation producing effectively.

Submit your Enquiry For Parts Here


Injector – 

Injectors are very delicate items, and well-performing fuel injectors are critical to good engine performance. Poor fuel quality can damage injectors, especially when fuel is impure or contaminated with water, soot, dust or algae. In the case where diesel injectors are worn, this will show in blue smoke from the exhaust on the machine. Diesel injectors on Caterpillar excavators moved from manual to electronic systems on the “C” series. Sigma have experience in getting injectors rebuilt, which is often the cheapest way to repair the engine.


spares parts


Air Filter – 

Air Filters are an important part of your machines. Diesel engines have a reputation for being bulletproof. Today’s models are no less durable than before, but due to changes in exhaust emissions technology, they also require extremely clean fuel and air to function properly. Fail to provide either and you could be looking at expensive repair bills.
Hot and dusty conditions prevail on many earthmoving jobsites. This means close vigilance is needed when it comes to airborne dust on the jobsite, but also maintaining a best-practices regime when it comes to your equipment’s air filtration. If the water truck breaks down or fails to show, your machines may be facing a huge increase in the amount of dust they must filter out of the intake air.
Dust contains silica, which if it gets into your engine, acts like a lapping compound. It is highly abrasive and when stirred into your lube oil, blown turbochargers or a dusted engine are likely results.

Cleaning air filters unwiselyair filter
Years ago it was common practice for operators to remove their air filters and clean them. Some used compressed air, some used a wash system; and as a field expedient technique some would just bang the filter on the side of the machine to knock the dirt out. Today this is not recommended for two reasons. “First, you reduce the effective future life of that filter by 20 to 40 percent every time you clean it,” “Second, you increase the likelihood that you’re going to open up holes in the media and that’s going to give dust a direct line to the engine or the safety filter. It’s putting a major piece of equipment at risk.
Once your filter reaches maximum restriction, you may not notice a performance change at first, but most modern engines will eventually start to deteriorate. At the next stage, the engine could force you to limp the vehicle back home. The engine does this to protect itself from further damage.
Know how your air filters work and how to change them to avoid big repair bills!
Air filters are especially necessary with modern electronic engines, which have much higher injection pressures and less tolerance to impurities. Any CAT, Wirtgen, Komatsu, Volvo or Dynapac equipment with electronic injectors will require high performance fuel filters to help prevent damage to the injectors. Alternative manufacturers to the main engine brands are Donaldson, Baldwin and Mann Hummel filters. Please ask us for a competitive quote for the filters you want to buy.


Engine Filters – 

Engine oil filters are changed as standard on most machinery engines every 250-500 hours. Engine oil passes through the engine block to lubricate it and provide cooling, toEngine Filter maintain a constant operating temperature. It is then recirculated into the oil sump, which acts as the central store of oil for the engine.
Engine oil routinely picks up contaminants, such as metal worn from the engine block, dust and dirt. This then collects as sludge and increases the wear in the engine.
Effective engine oil filters collect this mixture of contaminants, and ensure a lower wear rate in the engine, and longer engine life.
All diesel engines have engine oil filters, so whether your equipment is fitted with a CAT, Cummins, Perkins, Deutz, Komatsu or Volvo engine, you will need to replace the oil filters regularly.

In addition, changing the oil is also a requirement to maintain a healthy lubrication system, and maximise the life of your engine. For service intervals recommended for your machine, please enquire for a Maintenance and Service Manual for your machine. Sigma regularly supply these for our machines, and we would be happy to quote you for these.
Sigma can support you with your engine oil filter requirements, so please ask us for a comparative quote for the filters you need. We can price for Donaldson filters, Parker filters, Mann & Hummel filters, Parker Hydraulics filters and Baldwin filters, please let us know your requirements.

Fuel Filter – 

Fuel filters need to be replaced regularly. If water is not removed from a machine’s fuel system, the water will rust and corrode engine parts. Fuel-water separators pull the water out of the system. Just because a product claims to remove 100 percent of the water, doesn’t quite tell the complete story. There are two types of water, one is referred to as “whole water,” and the other is “emulsified water”.Filters
Hard-to-remove emulsified water usually starts out as whole water. As a piece of equipment bumps, bounces and jars its way across a work site, the fuel sloshes around. The more it is stirred, the finer the water particles become. As a result, they are dispersed throughout the fuel and eventually end up in an emulsion, which is difficult to separate.
Free water is visible. If you put it in a jar, you can see the water sitting on top of the fuel. That’s very easy to remove because it’s basically already separated. Emulsified water, on the other hand, has been mixed so well into the fuel that it is composed of very, very small bubbles that are almost attached to the fuel.
Fuel-water separators should be considered from two standpoints: the efficiency of the unit to remove particles and its efficiency in removing both types of water. The job of a fuel-water separator system is to protect the engine.
Given the high injection pressures of Tier 2 and Tier 3 engines, fuel cleanliness is a must. To make sure that the fuel is exceptionally clean when it reaches the injection pump, providers are switching to two-stage, low-micron filtration. The purer the fuel, the more efficient and long-lasting the engine and the machine. You can either use filters which are branded the same as the engine, eg Cummins, Caterpillar, Volvo, Wirtgen. These are called ‘OE’ which stands for Original Equipment, and generally charge a price premium for the peace of mind. These filters will usually be branded as CAT filters, Wirtgen filters, or Dynapac filters. Often warranties on engines are dependent on OE or Genuine filters being used. An alternative to OE equipment is OEM filters, or ‘Original Equipment Manufacturer’.

This is where suppliers who supply filters for machinery manufacturers like CAT also sell filters under their own brand. These are generally cheaper, and still excellent quality filters. The third option is to buy Aftermarket filters, where filter suppliers who have no relationship with the machine manufacturer produce replica filters which they sell as compatible to a make and model of engine. With aftermarket, you must be careful that the quality is good enough – some manufacturers in China produce filters which leak or do not filter to the required performance, which is simply buying yourself trouble.


Hydraulic filters –

Hydraulic systems on mobile plant, such as excavators, wheel loaders, bulldozers, crushers and screens, work on exceptionally high pressures and require very fine tolerances in order to maintain optimum working performance. If contaminants enter the hydraulic system, they can cause accelerated wear on both the pump, which provides the pressure to the system, and the valve block and hydraulic rams.Hydraulic Filter

In order to remove the impurities and contaminates in the hydraulic system, high-pressure, in-line hydraulic oil filters are usually used. These filters remove impurities and extend the life of the hydraulic pump, valves and other components.

All mobile plant which uses hydraulic power, for instance Caterpillar equipment, Volvo machines, Bomag road making equipment and Terex Finlay/Pegson/Powerscreen crushers and screeners, will all require hydraulic oil filters. You need to change these regularly, with either OE filters or OEM filters. Please enquire for a competitive quote for your filter requirements.


Sigma PlantFinder can supply all types of used and new Caterpillar engines. Caterpillar engines are not just fitted into CAT machines – CAT supply their engines as power units to Sandvik, Metso, Terex Powerscreen Pegson and Terex Finlay to drive quarry crushers and screens. Engines can be supplied with starter motor, alternator and fuel pump. We can also help with exhausts, ECU and replacement injectors. Please enquire for the model and condition of engine you are looking for, and we will advise our availability. Sigma has availability of engines in UK, Europe and USA, and we can quote for fast airfreight shipping times at good prices.