In contrast, my boss and his Dad liked their Leyland Constructors. They ran a D and a G reg both 6wheelers. They tried a Merc SK which replaced the D reg but they weren’t as happy with it overall. The service the Leylands’ gave them means they’re Daf loyal now. The only reason our puddle jumper isn’t a Daf is because Isuzu are much lighter and much cheaper.
Scania have used a modular cab system for years with the p cab r cab and top line added in now you have the g cab and the highline between the standard r cab and top line. Volvo offered the fl then the fm small cabs below the f and fh daf offer the cf below the xf.
Firms on the whole don’t seem as tight now but there was many firms buying fl10 and p cab scanias expecting drivers to be away all week round the UK or even on euro work. The drivers moaned about the lorry but it’s not volvos fault the firm didn’t buy the larger cabed vehicles that they offered.
Carryfast seems to have a bee in his bonnet about the TL12 but everyone else who has either driven or operated lorry’s with it seem to say it was a good engine of its era.
The engine wasn’t a new design it was a reworking of an existing design and any design has a limited life.
Scanias original v8 launched in 1969 was replaced by a new v8 design in 2000 as the original come to the end of its life and that engine wasn’t seen as a flawed design or a failure neither was volvos td120 which was replaced by tge new d12 when the fh was launched.
There was talk here that intercoolĺed version was good for 330/350 but was never released as leyland went down the assembly route which you can see making sense as guy and scammel customers would be used of dealing with various engines and by the mid 80s lay lands priority would be capturing sales of operators running other british makes which offered various engines so there fitters would be used to working on ■■■■■■■ rolls etc.
Daf got the reworked 680 up to 430 by the early 90s in the original 95 but they was ■■■■ compared to volvo and scanias offerings of the era
The LB series was modular too Kev, as were the 1700 through 3600 Dafs and the FIAT cabs used on everything above 10tons GVW, even the TurboStar was based on that cab structure. Door and windscreen apetures being the most difficult and expensive pressings, it made sense to keep costs down by using the same machines to manufacture the whole range.
The T45 cab range was a bold move by Leyland, it was one of the few stand alone cab designs around, many others had collaborated, the Club of Four being a good example and there were other shared cabs too, MAN and Saviem, Berliet and Ford, the Motor Panels cab used on Coles Cranes, ERF MWs, FTF, Guy, Scammell, Seddon and Shelvoke and Dewry to name a few. In development at the time of the T45 launch was the Cabtec joint venture cab, still used by Daf to this day.
Design and production of a complete cab that could be used by everything from a Roadrunner (with the substitution of a rear panel from a Sherpa van) to a Scammell S26 required a massive investment, as Daf found out when the 65/75/85 cab range sent the company into bankruptcy, from which it was bailed out by the Dutch Government before being sold to Paccar.
So don’t take the T45 range lightly, it was a massive undertaking to launch a complete range of commercial vehicles from 7.5tons up to a heavy haulage power unit, no manufacturer had done it before and only the biggest of them all (Mercedes Benz) has done it since and Leyland managed it despite the best efforts of the ailing car division’s to bankrupt the group.
Carryfast:
kr79:
Carryfast:
As for the SA 400 type cab are you seriously suggesting that the T45 let alone Marathon were both better competitors to the foreign onslaught from DAF and Volvo etc.I only drove a full width day cab constructor and the narrower cab on a constructor 6 and freighter and thought they was pretty good for the era and the roadtrain interstate looked good for the time.
I drove a Seddon Atkinson 3-11 and it is to this day the worst lorry I have ever driven and the later iveco cab bed ones were little betterI’m not sure if you’re just making the relevant comparison between the proper long haul SA 400 cab v T45.Or a totally different one based on relative differences in certain chassis componentry fit design and short haul day cabs,in which the SA’s advantages then probably won’t count as much.
Realistically the T45 carried over the type of relatively cramped cab design found in the Marathon.Not helped in the T45’s case by the ridiculous vertically tapering rear panel and screen lines adding to an already relatively short cab front to rear.Which was confirmed to me having driven the Marathon on some night out tramping haulage work together with a Volvo F10,and the T45 on trunking having been lumbered with one for a while at our depot,after a takeover of a firm by ours,which ran a Leyland fleet.In which,just like the Marathon,the T45 was a joke compared to the DAF 2800,or Volvo,cabs.While,admittedly never having had the opportunity to drive one,there’s absolutely no way that the physical dimensions of the SA 400 design couldn’t possibly have not provided something considerably better than the DAF and Volvo or most,if not all, other alternatives regarding space at least.Which seems to be confirmed here bearing in mind that the SA’s front to rear space has actually run out of camera shot.
Not sure where you are coming from here ,the Marathon was almost flat floored and quite spacious .The very first ones were available with a full sleeper the later ones with a shorter version , the 2800 Dafs were very cramped for me with the low windscreen another disadvantage , your beloved TM was available in many different guises ,the SA 400 was probably the worst of the bunch with the back to front gearbox and poor overall design ,the 401 being a much better vehicle. The T45 Roadtrain was available in rest cab ,full width sleeper and eventually interstate .
I think the the very first Roadtrains could have been improved with an option of the Fuller 9 speed or the ZF16 speed synchro instead of the Spicer and of course a Rockwell rear end which they eventually did 
As Newmercman said, they came in all shapes and sizes so it’s important to compare like with like.
Many manufacturers offered narrow/wide versions of their cabs, as well as short/long and low/high: Bedford TM, Eurotech/Star, Merc NG, and lots more besides. And that’s only the beginning because in comparing any two units you need to declare what your focus is: comfort, driveability, frugality, power and a dozen or more criteria. For example, I would rather spend all week living in a DAF 95:400 Super-Space than an ERF E-series E14:400 sleeper-cab; but I’d much rather drive the ERF all week than the DAF because of its driveline so that’s what I’d choose because my priorities and preferences are different from the next man’s.
All this business about one unit being better than another is very subjective once you’ve got the objective testing out of the way. Which is probably why NMM made his wry and entertaining comments about the Euro Tests! 
Robert
Reading NMMs comments on the T45 range would you think that the Ergo fit the same bill when introduced in the 60s .It didnt cover the 7.5 ton range but did Leyland produce a 7.5 tonner then . This cab would have been a large step forward when introduced not forgetting AEC never manufactured cabs relying on coach builders to do that. Maybe Leylands thinking was that they had produced what they thought was the most advanced cab of any British manufacturer at the time so they then concentrated on other aspects . I keep mentioning this but when they first introduced the Marathon surely they could have brought out a lowered version to cover the rest of the range not forgetting the original ergo carried on until around 1980 . The major drawback of the original ergo was poor air flow for the engine cooling , this at a time when the motorway building programme was gaining momentum , i remember in the mid 70s going across the M62 with my dad in an old Mandator wearing a jumper and big coat it was freezing with gaps between the doors and a driver passed us in a F88 wearing a t shirt ,both cabs were introduced around the same time
I think I am right in saying that Park Royal were part of the ACV group and had supplied cabs for AEC chassis up until the ?Sankey? Ergomatic cab was introduced.
cav551:
I think I am right in saying that Park Royal were part of the ACV group and had supplied cabs for AEC chassis up until the ?Sankey? Ergomatic cab was introduced.
Yes thats right but i think you had a choice of cabs at the time Harold Woods produced their own Duramin i think were another , what i was trying to say was their wasn`t 1 specific cab for AECs the customer had a choice where he got it from.When the Ergo was introduced their was no real choice but to be fair the Ergo was a big improvement on the coachbuilt offerings of the past. AEC had no real experience in producing home made cabs
I thought the Constructor was a good product. I would say that the 6 was the best six wheeler on the market at the time. As a tipper I always liked the constructor six much more than the eight even though it pitched up and down a lot more, but that would be typical of the difference between any 6 and 8 wheeler. The six had the advantage both from a driver’s and a fitter’s point of view in having a Fuller range change box rather than the horrible Spicer splitter fitted in the 8. The Spicer was I suppose specified because it had an aluminium casing rather than the Fuller’s iron one. I can’t be sure so many years later whether the 6 had a Lipe Rollway clutch or not, but the 8s we had at Tarmac used the simply horrible Spicer so-called self adjusting clutch. If, and it was a very big if, it worked properly then engagement of 1st/2nd from rest was better than with the Lipe, but normally the clutch brake wasn’t doing its stuff. The Lipe took no more than a couple of minutes to adjust; you could be freeing off a Spicer for ages since it didn’t seem to like clutch dust, which was rather an important failing considering what it was. The manual adjust version of the Spicer was better though. Seddon Atkinson fell into the same Spicer trap too IIRC.
Apart from a bit of third diff and top hat trouble the back end pictured below, didn’t seem to give too many problems. On the rare occasions a rear spring broke it was usual to find everything nicely seized, but that was normal for sand and gravel.The bogie trunnion frame used to crack quite regularly, but that was never too much bother.
cav551:
I thought the Constructor was a good product. I would say that the 6 was the best six wheeler on the market at the time. As a tipper I always liked the constructor six much more than the eight even though it pitched up and down a lot more, but that would be typical of the difference between any 6 and 8 wheeler. The six had the advantage both from a driver’s and a fitter’s point of view in having a Fuller range change box rather than the horrible Spicer splitter fitted in the 8. The Spicer was I suppose specified because it had an aluminium casing rather than the Fuller’s iron one. I can’t be sure so many years later whether the 6 had a Lipe Rollway clutch or not, but the 8s we had at Tarmac used the simply horrible Spicer so-called self adjusting clutch. If, and it was a very big if, it worked properly then engagement of 1st/2nd from rest was better than with the Lipe, but normally the clutch brake wasn’t doing its stuff. The Lipe took no more than a couple of minutes to adjust; you could be freeing off a Spicer for ages since it didn’t seem to like clutch dust, which was rather an important failing considering what it was. The manual adjust version of the Spicer was better though. Seddon Atkinson fell into the same Spicer trap too IIRC.Apart from a bit of third diff and top hat trouble the back end pictured below, didn’t seem to give too many problems. On the rare occasions a rear spring broke it was usual to find everything nicely seized, but that was normal for sand and gravel.The bogie trunnion frame used to crack quite regularly, but that was never too much bother.
Got to agree with these comments re the Constructor. Our early ones had the Fuller but the last one or two had the Spicer. Didn’t matter how you drove it always to seemed to get a “crunch” going in to top gear.
We were mostly on muckshifting and so we got more than the occasional broken rear spring, the u bolts were usually seized so came off via the burning gear. On the Bisons with the same suspension a snapped u bolt was a regular problem but didn’t seem to happen as much on the Constructor.We never had any trouble with the Constructor reduction hub, it seemed to be a lot more robust than the Albion type on the Bison.
Everyone complains about the 502 but coupled with the Fuller in the Bison made a good general purpose local tipper IMO. Yes the 502 had it’s problems but was light and powerful enough for our purpose. (could get a 15 ton payload on a steel body) In my experience it gave very few problems with fuel pumps and injectors (unlike the 400 series where black smoke was always a problem, Reivers !!! pile of !@+) when the 502 gave problems it was usually terminal, so we always had a spare engine ready to swap. Cab off, engine and gearbox lifted out together, gearbox fitted onto spare engine and then reinstalled and cab back on.dealerships
In all the discussions on this thread there seems to be very little comment on the quality of the dealerships that were selling the Leyland product. some were a lot better than others.
We had a B reg CONSTRUCTOR a 27 foot flat with a works sleeper cab a TL11engine and a FULLER RTX gearbox .It was a good wagon with a good payload and went well but the only problem we had and we never found the cause was blowing rear hub seals.The seals would go at any time we tried putting the Stemco oi lseals on dry leave them soak in oil nothing would work the axles were checked for cracks nothing found it was a mistery
newmercman:
What you have to take into consideration is the market that the T45 was aimed at, it wasn’t intended to better the Daf, Volvo, Scania ranges
From memory I don’t think that’s exactly how the T45 was marketed in the day on its introduction nor should it have been being Leyland’s last hope of turning the tide against the import invasion facing it.But if it was that would have been Leyland Truck’s suicide note contained in that statement. 
robert1952:
As Newmercman said, they came in all shapes and sizes so it’s important to compare like with like.Many manufacturers offered narrow/wide versions of their cabs, as well as short/long and low/high: Bedford TM, Eurotech/Star, Merc NG, and lots more besides. And that’s only the beginning because in comparing any two units you need to declare what your focus is: comfort, driveability, frugality, power and a dozen or more criteria. For example, I would rather spend all week living in a DAF 95:400 Super-Space than an ERF E-series E14:400 sleeper-cab; but I’d much rather drive the ERF all week than the DAF because of its driveline so that’s what I’d choose because my priorities and preferences are different from the next man’s.
All this business about one unit being better than another is very subjective once you’ve got the objective testing out of the way. Which is probably why NMM made his wry and entertaining comments about the Euro Tests!
I’d guess that the key in designing a winner is to combine the best all round features of both which in that example would be ERF putting a DAF 95 type cab on the ERF chassis.
Or in this case and point in time the T45 having a cab design to match that of the SA 400 and the ‘Rolls Eagle’ actually being the in house AEC designed engine,which the TL engine should have been,to put under it.
kr79:
Carryfast seems to have a bee in his bonnet about the TL12 but everyone else who has either driven or operated lorry’s with it seem to say it was a good engine of its era.
The engine wasn’t a new design it was a reworking of an existing design and any design has a limited life.
Scanias original v8 launched in 1969 was replaced by a new v8 design in 2000 as the original come to the end of its life and that engine wasn’t seen as a flawed design or a failure neither was volvos td120 which was replaced by tge new d12 when the fh was launched.
There was talk here that intercoolĺed version was good for 330/350 but was never released as leyland went down the assembly route which you can see making sense as guy and scammel customers would be used of dealing with various engines and by the mid 80s lay lands priority would be capturing sales of operators running other british makes which offered various engines so there fitters would be used to working on ■■■■■■■ rolls etc.
Daf got the reworked 680 up to 430 by the early 90s in the original 95 but they was [zb] compared to volvo and scanias offerings of the era
Firstly I think Leyland were forced down the outsourced engine route ‘because’ of the limitations of the TL12’s short stroke 690/760 based architecture.On that note Scania’s V8 and the Volvo TD120 certainly ‘would’ have been seen as flawed designs,probably sufficient to sink the respective firms, 'if they’d been designed with 114 mm and 142 mm stroke measurements respectively.
As for a 350 hp version of the TL12 yes that figure might have been seen as a flash reading on the dyno during development testing but that isn’t the same thing as running it at the types of specific torque figures needed,in service.Bearing in mind that in this case all of that increase has to be delivered by putting more stress through the piston to crank chain with no help from the extra leverage at the crank enjoyed by the longer stroke ■■■■■■■ and Rolls alternatives.
Which probably explains why Unicorns were more common than 350 hp TL12 powered T45’s. 
Carryfast:
newmercman:
What you have to take into consideration is the market that the T45 was aimed at, it wasn’t intended to better the Daf, Volvo, Scania rangesFrom memory I don’t think that’s exactly how the T45 was marketed in the day on its introduction nor should it have been being Leyland’s last hope of turning the tide against the import invasion facing it.But if it was that would have been Leyland Truck’s suicide note contained in that statement.
What foreign invasion? At the time of the launch (79 IIRC) the foreign manufacturers were all on their 2nd generation models, with 3rd generation models waiting in the wings, so it wasn’t an invasion at all, they were all firmly established by then, so there were no ifs, buts and maybes, the market was what it was.
Leyland chose to go down the same route with the T45 as the successful importers had done, namely a modern cab sitting on top of an in house drive line. You say the TL12 was a flawed design, but the competition had issues too, the Volvo F10, for example, came on the heels of the 290 F88 which, although loved by drivers, was in reality a dog, it wouldn’t start on a cold morning, drank diesel like it was going out of fashion and it was 50/50 at best as to whether it would complete a journey without blowing up. In revised form under the F10 cab it was not much better, at 300,000miles they needed pistons and liners in most cases as the liners went porous.
Then you have ULW, you weren’t getting 20ton on the back of an F10 unless you had a particularly light trailer and under the regs of the time if that trailer was 40’ long, you had a job keeping it within the overall length regs of the day, the T45 could easily achieve both. 2800 Dafs and 111 Scanias had the same issues.
So from a boardroom perspective, Leyland did all the right things, there is no way you can look at the project and say that they didn’t.
In my mind the biggest flaw in the whole T45 range was the badge on the grille, had it said anything but Leyland the T45 would’ve been a roaring success.
newmercman:
Carryfast:
newmercman:
What you have to take into consideration is the market that the T45 was aimed at, it wasn’t intended to better the Daf, Volvo, Scania rangesFrom memory I don’t think that’s exactly how the T45 was marketed in the day on its introduction nor should it have been being Leyland’s last hope of turning the tide against the import invasion facing it.But if it was that would have been Leyland Truck’s suicide note contained in that statement.
What foreign invasion? At the time of the launch (79 IIRC) the foreign manufacturers were all on their 2nd generation models, with 3rd generation models waiting in the wings, so it wasn’t an invasion at all, they were all firmly established by then, so there were no ifs, buts and maybes, the market was what it was.
Leyland chose to go down the same route with the T45 as the successful importers had done, namely a modern cab sitting on top of an in house drive line. You say the TL12 was a flawed design, but the competition had issues too, the Volvo F10, for example, came on the heels of the 290 F88 which, although loved by drivers, was in reality a dog, it wouldn’t start on a cold morning, drank diesel like it was going out of fashion and it was 50/50 at best as to whether it would complete a journey without blowing up. In revised form under the F10 cab it was not much better, at 300,000miles they needed pistons and liners in most cases as the liners went porous.
Then you have ULW, you weren’t getting 20ton on the back of an F10 unless you had a particularly light trailer and under the regs of the time if that trailer was 40’ long, you had a job keeping it within the overall length regs of the day, the T45 could easily achieve both. 2800 Dafs and 111 Scanias had the same issues.
So from a boardroom perspective, Leyland did all the right things, there is no way you can look at the project and say that they didn’t.
In my mind the biggest flaw in the whole T45 range was the badge on the grille, had it said anything but Leyland the T45 would’ve been a roaring success.
Would you think this was a case of having the trendiest motor of the the time a bit like when a new mobile phone comes out and theres a big rush to get 1 ,at the end of the day no matter how fancy the latest 1 is its there to make phone calls. Go back to the mid 60s and most drivers would have wanted an Ergo and most would want a triangle on the front because they were the latest thing. Fast forward 3 years and they would have wanted a V8 then the arrival of the Swedes and to a lesser effect the Germans and the Ergos were left behind.I for one found the 2800 Dafs cramped and ponderous and the Mercs just ponderous , i had an 84 Foden and i couldnt really fault it ,that after coming off a newer Turbostar with a bigger engine. I think youve got something there maybe an image thing , werent the first 95 Dafs badged Leyland Daf here but just Daf elsewhere ?
I don’t think it had anything to do with the image of the lorry itself, more the image of the company. We had all seen the news and Panorama type TV shows of the goings on at BL in the 70s, would you bet the future of your company on something that had been designed by the same people that brought us the Allegro and built by the same militant work shy lots at Longbridge? It didn’t matter that the truck division was a completely different kettle of fish, anything with a Leyland badge would be judged the same way.
newmercman:
Carryfast:
newmercman:
What you have to take into consideration is the market that the T45 was aimed at, it wasn’t intended to better the Daf, Volvo, Scania rangesFrom memory I don’t think that’s exactly how the T45 was marketed in the day on its introduction nor should it have been being Leyland’s last hope of turning the tide against the import invasion facing it.But if it was that would have been Leyland Truck’s suicide note contained in that statement.
What foreign invasion? At the time of the launch (79 IIRC) the foreign manufacturers were all on their 2nd generation models, with 3rd generation models waiting in the wings, so it wasn’t an invasion at all, they were all firmly established by then, so there were no ifs, buts and maybes, the market was what it was.
Leyland chose to go down the same route with the T45 as the successful importers had done, namely a modern cab sitting on top of an in house drive line. You say the TL12 was a flawed design, but the competition had issues too, the Volvo F10, for example, came on the heels of the 290 F88 which, although loved by drivers, was in reality a dog, it wouldn’t start on a cold morning, drank diesel like it was going out of fashion and it was 50/50 at best as to whether it would complete a journey without blowing up. In revised form under the F10 cab it was not much better, at 300,000miles they needed pistons and liners in most cases as the liners went porous.
Then you have ULW, you weren’t getting 20ton on the back of an F10 unless you had a particularly light trailer and under the regs of the time if that trailer was 40’ long, you had a job keeping it within the overall length regs of the day, the T45 could easily achieve both. 2800 Dafs and 111 Scanias had the same issues.
So from a boardroom perspective, Leyland did all the right things, there is no way you can look at the project and say that they didn’t.
In my mind the biggest flaw in the whole T45 range was the badge on the grille, had it said anything but Leyland the T45 would’ve been a roaring success.
Firstly we know that Leyland was supposed to be all about an in house ( vertically integrated ) manufacturer wherever possible.In which case there’s no way that it was going to do that and be a competitive player in the market without at least using the 2800 and F12 ( not the F10 ) as a benchmark.
Which then leaves the fact that both the TD100 and the TL12 had one thing more or less in common.That being stroke measurement.The unarguable mathematical result being more stress and/or more engine speed and compromised reliability needed to do the same amount of work as opposed to the 2800 let alone F12 or anything with a decent spec ■■■■■■■ or Rolls in it.
While as history proved the idea of bigger long stroke engine and decent big comfortable cab rightly won out over any arguable pay load considerations.All of which was foreseeable in the 1970’s at least and would have been doable at that time on an in house basis and maybe then even just branding the whole Leyland heavy truck range as Scammells.
While even if it was by that time ‘established’ Leyland still had a mountain to climb in turning back what was still an import ‘invasion’ of products like the 2800/3300 and F12 among others and there’s no way it was going to do that with the T45,let alone Marathon,cab and TL12 engine. 
We’ve been down this road many times, maybe I’m wasting my time, but I’m going to say it anyway. Over 300hp lorries were the exception in the 70s and early part of the 80s, by using the F12, 3300 etc as a comparison you are doing the apples to oranges thing again.
The bigger lorries on the road at the time of the T45 design were in the 250-300hp range and so that’s where the mainstay of the range should ideally be aimed. From there once the model is established you then bring out a range topper, just as the competition did. Again we’ll use Volvo as an example, first came the F88 and then the range topping F89, they did the same with the F10 and F12 to a lesser extent, mainly because they had already broken ground with the F89, so the F12 wasn’t such a major engineering project.
