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Thanks to several facelifts and upgrades, Mercedes-Benz got well over over 20 years of life from its SK cab design, which can be regarded as a classic of its time
Words: Pip Dunn The raked Mercedes SK cab broke cover in 1973 and became one of the most familiar vehicles on the road not only in Europe, but across the world. In the UK it was one of the most popular trucks, until replaced by the Actros in 1996, which in its original form has ‘only’ lasted until 2011 courtesy of two facelifts.
When the new trucks were first sold in the UK in 1974, they were up against not only the first of the imports from Daf, Volvo, Scania and German compatriots Magirus Deutz and MAN, but also against a then-healthy UK manufacturing base – which included ERF, Foden, Guy, Leyland, Bedford, Ford, Atkinson and Dodge. It was a tight market and any newcomer, especially one from across the channel, had to be good.
Sadly for the UK manufacturers, the Mercedes trucks were good. Very good in fact. The LPS cab-over engine and LS bonneted trucks had already started to win over traditional UK-buying customers, and the new SK range raised the bar even higher. It was a stylish design that was almost ahead of its time.
UK manufacturers were slow to respond and when the SK came out, alongside Daf’s 2800, Volvo’s F88 and Scania’s 110, UK truck builders were still turning out Atkinson Borderers, ERF A-series and Scammell Crusaders (although it was not long before the Seddon Atkinson 400 and ERF B-series appeared).
The new generation
The initial new generation Mercedes SK models that replaced the LPS range were the 1619, 1626 and 1632 fourwheel tractors and the 2026, 2032 and 2232 six-wheel tractors – the former two 6x2 twin-steers the latter a 6x4 double-drive. Rigids were the 1619 4x2 and the 2419 6x4, while for drawbar applications there were the 2619, 2626 and 2632 versions.
Engines were the naturally aspirated OM401 192hp 9.5-litreV6, OM402 256hp 12.7-litre V8 and OM403 320hp 15.9-litre V10 – the latter rather meaty for the era. In the UK only the V6 and V8 models were offered.
The initial cabs were the S-day cab, the short M-type sleeper and the L-sleeper. Despite its cramped size, the M-cab was available as a double bunk option, while the L-cab had a double bunk as standard, although there was also a single bed option. In 1975 the new cab was used on lighter trucks with engine options including the smaller in-line six-cylinder engines – the OM352 5.77-litre 130hp and the turbocharged OM352A at 168hp – as well as the OM401. These were the 1013, 1213, 1017, 1217, 1417 and 1419 4x2 rigids. The smaller 7.5-tonners still used the older LP cab (a smaller version of the LPS cab) and did so until 1984 when the new LN range was unveiled.
From 1979 a new 1638 was offered on the Continent, with the new twin-turbocharged V8 14.62-litre OM422LA engine producing 375hp and featuring the wider G-sleeper cab.
This engine was a beefed-up version of the also naturally aspirated OM422, 276hp unit, which was put in the new 1628 model while the OM427A – a turbocharged version of the same bore – produced 350hp.
That same year, as well as the new 1628 and 1938 models, Mercedes unveiled the 1625 to replace the 1626, while the 1617 superseded the 1619. The range was enhanced with the new 201hp 1621 and turbocharged 328hp 1633 models, which were offered in the UK.
Weight increases
In 1983 UK hauliers were preparing to embrace increased legal maximum weights as the 32.5-tonne limit was upped to 38 tonnes, albeit with the need to move from four to five axles.
Many who had four-wheel tractors found it cheaper to add an extra axle to their tandem-axle trailers, while others opted to do the same on their tractors – a more expensive modification, but one which brought the added benefits of cheaper tax and less likelihood of suffering an axle overload either when fully laden or as the load diminished during the day’s deliveries.
But for those operators buying new kit, either to replace existing trucks or to meet the new weight limit, manufacturers were quick to offer new three-axle tractors. These also came in different types. Most 6x4s were generally deemed to be too heavy, as the added axle usually had single tyres and was either a lifting tag axle behind the drive axle, or a steering or pusher axle in front of the drive axle.
Mercedes was quick to meet the UK’s need with the twin-steer version of its 1628 4x2 tractor.
The 2028, as it was badged, used that whopping 14.62-litre V8 engine that was naturally aspirated and produced 276hp, just over 7.25hp a tonne. It was offered with all three cab options; the S, M and L.
If the 2028 was deemed an extravagance, then in late 1983 Mercedes announced the twin-steer variant of the 1625; the 2025. Also offered with the three cab options, the 2025 had the same OM422 V8, but developing just 247hp, spot on 6.5hp a tonne. In today’s equivalent at 44 tonnes, that would be battling along with a 286hp motor.
For the long-haul operator, however, there was a twin-steer Mercedes with a little bit more beef, the 2033, which had the 328hp OM422A engine.
This was only available with the L-sleeper, although haulier Jeff Skellern persuaded Mercedes to sell him the wider G-cabbed version 2033 in 1985. The 2033, the twin-steer version of the 1633, was unveiled in 1979.
The 2025 might have been deemed quite gutless by many operators, even by 1984’s standards, but it didn’t stop Ferrymasters buying a fair few of them with the L-cab. Even the 2028 found favour; Birmingham operator Chambers and Cook regularly took them abroad, while the 2033 was the wagon of choice for trampers and Continental operators.
In 1985 the 1635 and 2035 were added to the range, at 350hp edging ever nearer to the 10hp per tonne hauliers favour as the minimum requirement today. At the same time, the hitherto power conservative Mercedes offered the new king of the power stakes – the awesome 1644.
This featured the full-width G-cab, but there was not a twin-steer offering as a 2044, although some operators did add extra axles, usually rear-lifting tag axles, a feature that was not part of the Mercedes range.
A visual facelift
By 1988, the SK was 14 years old and while there had been much improvement under the cab, the exterior was the same, albeit with a change from silver model designation badges to black plastic in the late 1970s.
The SK range had the first of many external facelifts in the late 1980s and early 1990s. The autumn of 1988 saw the first most notable change. While the cab structure remained the same, new side windows on the doors gave the new range a smarter look. The front grille was changed to extend the full width of the cab behind the side dirt deflectors, while the bumpers were ‘flattened out’ vertically. Oh, and the model designation badges changed again, this time to raised polished silver on a black background.
The changes saw the 1625 and the 2025 swapped for the 1726, with no twin-steer option. The 1628/2028 were replaced by the 1729 and twin-steer 2429 with the OM442 V8 15.08-litre non-turbocharged lump – also used in the 1726. The new 1733 and 2433 were offered with a novel V6 OM441LA 10.96-litre engine as was a new 1735/2435, while the 1644 metamorphosed into the even more powerful 1748 – the latter two having turbo-intercooled versions of the OM442 14.62-litre engine for which a 2448 twin-steer was available. There were also the 2426, 2429, 2433, 3229 rigids.
The next facelift for the SK range came in 1991 and was kept to under the cab. The range was changed to the 1827 (272hp OM401LA), 1831 (313hp OM401LA), 1834/2534 (340hp OM441LA V8), 1838/2538 (381hp OM402LA V8), 1844/2544 (435hp OM442LA V8) and 1850/2550 (503hp OM442LA V8).
Rigids saw the 2422 and 2427 6x4s for construction applications, the 2531 6x2 for drawbars and 3234 8x4 for tippers. This upgrade saw the new Eurocab high-roof cab (CM Feb 9 2012) added as an option on the L and G sleepers.
A minor facelift – evidenced by a new grille and different badges – was introduced in 1994, which also saw a new 1853/2553 model added. This was the last throw of the SK dice because in 1996 the Actros range appeared. The SK cab lingered on in production for rigid trucks until the Atego appeared in 1998.
Worldwide and preservation
The SK range has proved durable throughout the world, and was commonplace almost everywhere, with the exception of North America. Part of the reason you see so few still at work in the UK or on the preserved circuit is because masses of late series models were exported to Africa and South America.
The cab design was also used by other manufacturers, especially in Eastern Europe, such as Fabrika Automobilia Priboj (FAP) in Yugoslavia. It can also be seen on some Tata vehicles in India.
Among the trucks preservation movement, the SK range hasn’t captured the imagination as much as the big Scanias and Volvos, although a few are on the circuit, and Mercedes UK recently restored an 1838 to showroom condition while an 1834 was on display at last autumn’s Retro Truck show.
It is possible to see the odd SK on the road today, especially the 1820 rigids which lasted in production until 1998, but tractors are now pretty rare, although the odd 1834 or 1838 remains. That said, flick through the pages of CM’s classifieds each week and every now and then there will be an SK for sale. ■