The Commercials : Leyland T45 Constructor

 AROnline gets down in the dirt as we take another look at the T45 cab system Leyland introduced back in the early 80’s. Another big seller in the commercial vehicle sector was the Leyland Constructor – a range of 6 or 8 wheel vehicles up to 30 tons GVW. Mike Humble gets into gear and takes a journey back…

This official Leyland picture was taken in 1980 – The T45 cab still looks modern 32 years later!

The T45 Constructor 6 & 8 replaced the elderly but hard working Bison & Buffalo ranges that had been the stalwart Leyland tippers through most of the 1970`s. Leyland’s chassis engineering had always been excellent so little was changed in this respect with the exception the front most section of the ladder frame to accept its new cab. Much improvement had been made with its braking systems too in recent years, so all in all it very much a case of improving and modernising a decent formula.

Getting to grips with engineering:

The Bison had originally been fitted with the revolutionary yet disappointing 500 series fixed head OHC high speed diesel, but following Leyland modernising its legendary 680 unit into the L11 & TL11, towards the end of its life the Bison became a hard act to follow for operators both fleet and owner driver looking for a no frills, hard grafting machine. Towards the end of the 70’s it became obvious that no matter how reliable it had become, it was dated by design and had its roots from Leyland & AEC designs going back to the 60’s.

The Constructor was launched in 1981 in 6 or 8 wheel format with both rear bogies and front axles along with its chassis being directly carried over from the Bison. Its cab was also based on the Road train or Cruiser in ‘low datum” form on six wheelers and ‘high datum” on the eight, with either a day or sleeper cab. Six wheeler tippers were initially fitted with Leyland’s relatively new TL11 6 cylinder high torque diesels with power options of 181 or 209bhp, higher power options up to 260bhp came later.

Alternative power units:

The eight wheelers could be opted with Rolls 220 or the Gardner 6LXC-T 230 but no other engine options were offered on the six. In order to keep existing drivers happy, Leyland opted not to change too much as far as gearboxes were concerned, opting to use the familiar Eaton 400 which had it roots as far back as the old AEC Mandator. For heavy duty applications the 6 wheeler could be ordered with a nine speed Fuller transmission, while the eight could be fitted with a 10 speed Spicer gearbox.

Its tandem rear drive axles with hub reduction gearing were also carried over from earlier designs and were the source of some trouble on earlier Constructor’s with cases of half shaft failure being known during arduous working. Other problems these vehicles suffered were damage to the bottom of the radiator owing to a poor design of radiator guard on the 6 wheeler and fractured wheel studs were not uncommon, though once various lessons were learnt, the Constructor proved to be popular in service.

Class leading credentials:

Inside the cab, the plush carpeting found in the Roadtrain was substituted for a thick padded rubber flooring to ease the mucking out at the end of the day and a vinyl seat trim could be specified in lieu of the tartan cloth if requested. As the years progressed, the engine options expanded and the eight wheel Constructor could be offered with power from Perkins as well as Cummins, the latter option being very popular with owner drivers. Power ratings varied right up to 300bhp and the Constructor 30:30 was the most powerful tipper on the market for a while.

The most famous Popemobile was this 1982 Constructor 6 which recently sold at auction for £37.000

To cope with the extra power and to keep production costs down, the Albion sourced double reduction rear axles on the 30:30 were substituted with units supplied by Eaton. Fame came to Leyland with the Constructor 6 being chosen as the ‘Popemobile” for his 1982 UK tour, and some readers may well remember the Not The Nine O’ clock News sketch – `I Like Trucking” with HGV licence holder Rowan Atkinson at the wheel of a press demonstrator Constructor. As with the Road train, shortly after the merger with DAF trucks, some product revisions or deletions took place.

Product rationalising & re-engieering:

The Constructor range was re-badged as the 60 series, and at the same time Leyland’s own power unit was phased out along with all the other engine options. A DAF sourced 11.6 litre in line 6 with 300 or 330bhp available, itself a development of the Leyland 680 became the sole power unit. Standard transmission became the Eaton 12 speed twin splitter, while at the rear, the Leyland/ Albion U25 hub reduction axles were replaced by the well known and robust Rockwell type. Production was eventually phased out in 1994 with the launch of a new DAF designed 85 series / CF range, of which CF production continues at Leyland.


Mike Humble


  1. I couldn’t help looking for Rowan Atkinson’s NTNON ‘I Like Trucking’ sketch and found it funny and brilliant – thanks for the heads-up! 🙂

  2. I wonder what the person who bought the popemobile will use it for?  I guess it would make an OK campervan if you made curtains to cover the windows, although it would be rather an expensive one!

  3. @Mike – thanks for the NTNON link – I’ve never seen that programme before (I would have been about seven at the time) and it’s superb!  Now going on YouTube to watch some more.

  4. @Mike – Think BCVM Leyland still have Popemobile SCW533X.  There were two made and at one point they had both.

  5. I Like Trucking – Brilliant! Love the P6 in front of the truck (4 cyl). As it was said “It still looks modern” and I do agree. Trucks have not progressed much in style.

  6. Constructor 8s were developed and built at Watford at the Scammell works then I believe production moved back to the LAP at Leyland with the Scammell closure. The 8 had the premium (full width) cab and choice of engines, including RR & Cummins whereas the 6s had the lightweight (narrow cab)and Leyland engines, either 411 (160) or TL11D (190) or TL11A (220) originally. Only the 6 had the 4 spring T14 bogie, or 6 and 8 could both use the T6 2 spring.

  7. Hi all,
    Could anybody please help. I am considering buying a leyland 8×4 (T45 I think)for work.It is H reg with rolls royce 265 diesel & 9 speed spicer gearbox. I would be obliged if a knowledgeable person would comment on this layout,
    ciaran dempsey

  8. Hi All,

    There was also an 8×4 Constructor with the ‘narrow’ six-wheeler cab & engine / transmission options offered, designated Constructor 30.26. Here is an image of one from flickr:

    In my opinion this made a much better looking eight-weeler than the ‘wide’ cab versions.

    Please can we ensure that this varriant features in ‘The T45 Book’?

    Best regards, Andrew.

  9. Don’t forget the Scammell S26 when you come to do the book.

    The company I worked for British Fuel Company (Sheffield), we had a Freighter 160 Turbo and a Constructor 6 24.21 Bulk Tipper Coal Blowers.

    The 6 was a dog, and anything that could go wrong with it would. We tried to get it replaced even though it was only 7 years old. The Freighter was okay, only trouble was a gear linkage that would break. ZF Nottingham kept no stock and it would take a day for the part from Germany.

    We looked a the lightweight 8×4 as an alternative, we were going to have a partition door halfway along, so 2 deliveries could be made without going back to the Pit. The onboard weigher was another option, but it wouldn’t be authorised as legal delivery note at the time.

    I put a big tender out in 1991 to all the local Commercial Vehicle Sales firms, (except, M.A.N.(Didn’t do a 6),Foden & Renault who had no presence in South Yorkshire) and it came down to the Volvo FL7, E.R.F ES8 with a Cummins 265bhp engine or the Leyland DAF (can’t remember what it was called at that time). I wanted the E.R.F.

    (Disappointed that Seddon Atkinson couldn’t meet the criteria, on length. The Iveco EuroCargo 6 hadn’t come out yet).

    Anyway. You might want to try the Open University. They did a programme on the T45 cab. Saw it during an insomnia period. Interesting that the Leyland Committee, had been informed by the Labour Government of 1975, that Women would make up 25%, of all the HGV Drivers in the future. So it went on, and they got a current Female Lorry Driver, and she said, “You want a good, reliable and powerful engine, lots of gears that you can change quickly and smoothly and Brakes that Don’t Fade. She was driving a Scania Series 3.

  10. Hi,we ran a fleet of 8x4constructors the first had a TL11A,david brown six speed gearbox and albion hub reduction gearbox. The second had a 6LXCT gardner with spicer gearbox. We also had ones fitted with rolls 265l,265li,300li and 300le engines,and fitted with rockwell axles,and even an oldball running soma axles.

  11. My brother has a t45 260 turbocharged, and I’m looking for a gearstick 5 speed splitter he has no chassis number can anyone help, his truck is in the west indies

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