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R emanufacturing has always been popular with UK operators. According to
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remanufactu ring specialist HL Smith, when a gearbox fails 70% of truck operators will buy a service-exchange box.
Remanufacturing (reman), or service-exchange, rather than repair, suits the busy UK operator. "Reman cuts down time to a minimum and you receive a rebuilt unit with a warranty" says Russell Smith, HL Smith's managing director. "With repair you run the risk that another component will fail in a few months. meaning more downtime.A repair rather than remanufacture makes sense only if the vehicle is shortly to be disposed of or nearing the end of its life."
Smith says operators should beware of any remanufacturer offering a quick, cheap, fix: "It is essential to strip down the unit to discover the extent of any hidden damage that might affect performance once it is back in service. Whatever core parts are reused, you should always expect the 'soft kit' —the gasket seals, bearings and 0-rings, for example—to be replaced with new parts."
If you are replacing the gearbox, Smith recommends replacing the clutch at the same time to prevent problems later.
There is a similar focus on quality control at the ArvinMeritor's Maudslay drive-axle reman plant in Warwickshire, where production will be increased soon to offer remanufactured brake calipers.
Production manager Andy Hawkes says: "Service-exchange units give a consistent quality at a price that is often more competitive than a workshop repair."
The saving in downtime can he considerable, he points out:"Once the truck is in the workshop, you have to drain the oil, remove the half shafts and withdraw the diff head. That's just to reach the point where the unit can be stripped down to ascertain what parts are defective and need to he ordered. You then wait for the parts Lobe delivered and schedule the repair in the workshop.lhat assumes your initial diagnosis as to the fault is correct."
By way of contrast, there is a 24-hour turnaround for a service-exchange.
Rejects binned
Again, the emphasis is on saving cost by reusing parts that might fail later-but out go bearings, seals, fasteners and any component showing pitting or scoring. It is important to keep crown wheel and pinion as matched sets, says Hawkes— so if one part is rejected, the other is destroyed to prevent its accidental return into the system.
All rebuilt units are subject to a load test to check that performance will be as good as a new axle; they are also subject to a noise test using the same end-of-line test checks used on new diffs. Indeed, the computerised stockcontrol system will not issue a stock number for a rebuilt unit until it has a record of this end-of-line test.
Rernanufacturing has even become popular with some OEMs (original equipment manufacturers). Scania, for example, promotes a range of 'recycled' parts.
With smaller components, the cost-benefit between buying new and remanufacturing has become even more blurred over the past couple of years, with increasing numbers of `will-fit' (non-OEM) parts on the UK aftermarket. These are often sourced from emerging economies such as India and China and are attractively priced, even compared with remanufactu red parts Some parts factors are introducing their own brands of will-fit parts.
"Replacement or remanufactured parts built to the original OE specification will deliver similar service life to the original," according to Tim Ford, sales and marketing director at Knorr-Bremse."Those standards are constantly rising."
Ford cites double-diaphragm parking brakes as an example: "Originally these had to perform 500,000 actuations to meet OE requirements. Now it's one million actuations. When we remanufacture it's to the same standards. Other remanufacturers will reuse the old spring but in our view this is not acceptable as it might result in below-par in-service performance."
If the original parts supplier does not offer a Tema nufactured part. there is usually a good reason for i t, says Ford."Components are more complex on modem vehicles and less easy to remanufacture. Our four-way multicircuit protection valve, for example, is small and doesn't look complicated from the outside. But it does a complicated job of receiving air from the compressor and delivering it to four different tanks on the vehicle, often at different pressures.
Reman unviable
"There are a lot of small internal parts and we do not remanufacture these valves because the time required to do it at a consistent quality makes it unviable."
Trailer running-gear specialist BPW also reports finding poor-quality will-fit replacement parts on the market. BPW tested air bags from different manufacturers, all visually similar to the BPW air bag.While some had plastic pistons, others had metal ones (plastic is preferred because it is non-corrosive, lighter and less abrasive on the rubber bag).The roll property of some bags was also suspect — important if the trailers are regularly carried on ferries.Technical manager Peter Wray explains: "The air bag stretches on these operations and it needs to rollback over the piston cleanly and without kinking or it will crack."
On disc brakes, BPW found a will-fit part that had a 45% worse in-service performance than the BPW disc, mainly as a result of unsatisfactory cracking. Original discs are designed and tested to perform at thicknesses from 45rnm when new down to 37mm."One of the discs had three cracks on it within a very short period," Wray reports. • CONTACT
Knorr-Bremse: 0117 984 6223 ArvinMeritor: 0845 6067733
HL Smith: 01902 373011 Remy Automotive: 01543 442 180