Leyland Royal Tiger Questions

[RK215]

As seems to have been well-recorded in the Australian literature, but equally steadfastly ignored in the British literature, the Sydney Leyland Royal Tiger OPSU1 fleet was specially fitted with AEC air-operated preselector gearboxes, as were Sydney’s contemporary Tiger OPS2 and Titan OPD2 acquisitions. Auckland also had preselector-equipped OPSU1 Royal Tigers.

Were there any other Australian Royal Tigers fitted with AEC preselector gearboxes?

And somewhat the reciprocal of this question, were any late Australian Royal Tigers fitted with Pneumocyclic gearboxes? Leyland released the Pneumocyclic a bit before the Royal Tiger was superseded by the Worldmaster, and although it was never offered as a regular option on the Royal Tiger, some late examples for South Africa were so fitted. Conceivably there could have been some in Australia, as well.

The Sydney preselector Tigers and Titans had the AEC gearchange lever mounted in the usual AEC fashion, that is with the shaft somewhat skewed so that it entered the floor behind the steering column. The Auckland Royal Tigers had a neater arrangement, with the gearchange shaft arranged parallel to and left of the steering column. They also had a treadle-type brake pedal, unusual in Leyland bus practice. I assume that the Sydney Royal Tigers had a similar arrangement, but not having seen one, I don’t know for sure.

The Auckland Royal Tigers were quite nice buses from a passenger viewpoint. Certainly, they couldn’t match the Daimler Freelines for outright performance, but the engine noise was neither excessive nor obnoxious in note, such that they always seemed “unfussed”. Also, the gearchange seemed swifter than that of the Freelines.

Were there any of the long version of the Royal Tiger (OPSU2, 20 ft 4 in wheelbase) in Australia? I am not aware that any such were used by the city fleets, but perhaps there were small numbers in some private fleets? Insofar as the long vertical-engined Tiger (OPS4) was sold in Australia, there could have been a market for the OPSU2, although both must have been noticeably underpowered with the O.600 engine.

Thanks in advance to anyone who can help.

Cheers.

[Rail Bus]

Ok, here's what I DO know! The pre-selector gearbox, whilst used extensivly by AEC, was NOT owned or patened by AEC. (AEC = Associated Equipment Company) All post-war AEC Regent III chassis used in Sydney had this style of gearchange. The Regal IV's 2753 to 2811 were fitted with pre-selectors, then the 1955 builds onwards were fitted with an electro-pneumatic gear control, consisting of a "Mono" control for the gearchange, and an EP unit mounted on the chassis at the gearbox.

The Leyland OPSU1/1's all had pre-selectors and a Leyland 600 motor. The only "Titans" to have a pre-selector were the 50 Clyde bodied OPD2/14 (I think that's there correct designation) that had an air-operated front door, along with those bodied as 31-Seaters. (Frogs) Some Adealide "Jumbo" AEC's had pre-selectors also. I will ask The Inspector on that and see if he knows. The pre-selector gearbox box was part of the Wilson Self Changing Gears patent that goes back to atleast the 1920s. This paved the way for the Pnuemocyclic gearbox, and later the fully automatic gearbox that we use widely today.

Try PM'ing Vash The Stampede if you want realy detailed info on pre-selectors and pneumos.

[Herbert]

On an AEC forum someone has been doing some research into Wilson gearboxes and patents. Here's his findings:

19?? - Wilson patents preselective epicyclic gearbox developed for WW1 tanks.
1930 - W.G. Wilson's preselective epicyclic gearbox first appeared.
193? - SCG set up to administer patents
193? - built under licence Armstrong Siddeley
193? - Armstrong Siddeley boxes married to fuel flywheel by Daimler.
193? - Daimler made there own version with brake bands wound opposite way to Armstrong.
193? - AEC made there own version with bands correct way (Self Tighten on application).
1948 - AEC Air operated preselctor box fitted to RTL/ RTW
1952 - SCG taken over by Leyland who make there pnemocyclic direct selection rather than pre-selector box.
195? - AEC introduce there Monocontrol version.
195? - Daimler introduce there Daimatic version still with bands opposite way which causes problems on Fleetlines.
196? - AEC stop making monocontol boxes
19?? - SCG taken over by Cummings

Just for the record, there were 26 Royal Tigers in Perth, all new to the Metropolitan Omnibus Co & passed on to the MTT. All of them were conventional 4sp synchromesh.

[Windy]

On an AEC forum someone has been doing some research into Wilson gearboxes and patents. Here's his findings:

19?? - Wilson patents preselective epicyclic gearbox developed for WW1 tanks.
1930 - W.G. Wilson's preselective epicyclic gearbox first appeared.
193? - SCG set up to administer patents
193? - built under licence Armstrong Siddeley
193? - Armstrong Siddeley boxes married to fuel flywheel by Daimler.
193? - Daimler made there own version with brake bands wound opposite way to Armstrong.
193? - AEC made there own version with bands correct way (Self Tighten on application).
1948 - AEC Air operated preselctor box fitted to RTL/ RTW
1952 - SCG taken over by Leyland who make there pnemocyclic direct selection rather than pre-selector box.
195? - AEC introduce there Monocontrol version.
195? - Daimler introduce there Daimatic version still with bands opposite way which causes problems on Fleetlines.
196? - AEC stop making monocontol boxes
19?? - SCG taken over by Cummings

Just for the record, there were 26 Royal Tigers in Perth, all new to the Metropolitan Omnibus Co & passed on to the MTT. All of them were conventional 4sp synchromesh.

Yes my dad had worked on the Saracens and Saladdons (spell check??) and both were pre-select gearboxes. I couldn't get my head around it when dad explained it to me and when we went for a spin in one of each (which have been preserved by the Royal Australian Corps of Transport by 11th Movement Control Group as it was known when at the Maritime School/Middle Harbour. A LARC was also parked at the Maritime School, but now not much of the aforementioned remains, and it is now officially known as Clifton Gardens.

[boronia]

The Monocontrol system (and later Auto-monocontrol) for the Wilson gearbox used by AEC, and on the second batch of Sydney ERTs, and later on Volvos and other makes, was developed and made by CAV, the electrics company.

It's along time since I have driven a Leyland OPSU1 preselector, but I seem to recall that the actual head with the gearchange lever was slightly different shape to that of the AECs. Presumably the OPD2s had the same unit.

[Rail Bus]

The Monocontrol system (and later Auto-monocontrol) for the Wilson gearbox used by AEC, and on the second batch of Sydney ERTs, and later on Volvos and other makes, was developed and made by CAV, the electrics company.

You're right, Boronia. I had forgotten that part of things. I should have remembered this as I drive a mono-control B58 from time to time as well as the odd Leopard with a Mono, and have seen crate loads of the EP units.

As for the difference in control between AEC and Leyland on the Underfloors, I will have to have a look next time I go to the parker yard. They have so much that I can cross reference many styles of ex-Sydney bus all in one place.

[boronia]

In most of the photos I've seen of Atlanteans in the UK, they have monocontrol rather than pneumo-cyclic control. The latter seems not to have been so popular there??

[boronia]

[
Yes my dad had worked on the Saracens and Saladdons (spell check??) and both were pre-select gearboxes.

The smaller Daimler Ferret scout cars also had the preselector box, along a separate reversing box; so you had four gears in either direction. Obviously handy for beating a hasty retreat

[RK215]

In respect of the Wilson epicyclic gearbox history, AEC had developed the air operated preselector version a little before WWII, in part for the LT RT. Previously, AEC had tried a vacuum-operated version, with external vacuum cylinder, evidently not very successfully. (With hindsight, vacuum assistance, with a servo in the mechanical linkage, might have been a better way to harness vacuum power.)

The direct air operated version, with internal air cylinders, was also developed before WWII, albeit only for the larger sizes used mostly in railway applications. For example, New Zealand Railways in 1939 acquired some Tr class 0-6-0 shunting tractors (with Leyland 10-litre petrol engines) fitted with air-operated epicyclic gearboxes, with direct air control (by a disc valve, I think). Its 1940 Vulcan railcars had the same type of gearbox, but with electric control to facilitate MU working. It was inevitable that these techniques would find their way into the smaller road vehicle epicyclic gearboxes. However, it took around 15 years, and then Leyland promoted it as if it were a major breakthrough. Given that it was a major about-face by Leyland, that’s probably not too surprising.

Leyland used the “Pneumocyclic” name both for its original version with the classic pedestal type direct air control, and its later version with the CAV electric control. “Monocontrol” was an AEC trademark, and although Leyland inherited ownership it after 1962, I don’t recall that is was applied to other than heritage-AEC models.

As far as I know, the Tiger Cub PSUC1, Titan OPD2, PD3, Tiger OPS4, Worldmaster, Royal Tiger Cub RTC1 and Leopard PSU3/4/5 all had the direct air pedestal type shift as standard when the Pneumocyclic was fitted, except for the automatic versions from circa 1959, which necessarily had the electric shift. (Both CAV and SCG itself developed automatic control mechanisms.) However, there were variations, presumably according to customer requirements.

Leyland’s routine use of the electric shift seems to have started with the Atlantean PDR1, followed by the Lion PSR1, Panther PSUR1 and Panther Cub PSRC1, for all of which it was standard. However, in the late 1960s, the Atlantean switched to the pedestal as standard. In the 1970s, the pedestal also found its way on to the (heritage-Guy) Victory II (and maybe it also been used on the preceding Victory J). I don’t know if it was ever used on a Reliance, though. Some of the 1970s pedestals had detents that required sequential downshifting, i.e 4 to 2 via 3, not directly.

Daimler may have been the first to declare its interest in an internal oil-operated version, consistent with its interest in power hydraulics, but settled for the hydraulically assisted preselector version, as introduced on the CD650. LT was similarly interested; in this case, although the design work had been done, AEC declined to build it, which is why the RM had the Monocontrol. (With automatic operation and no throttle dip – evidently made feasible because LT used its own design of band automatic slack adjuster.) Thus, Midland Red was the first “bulk” user of the oil-operated version, for its own-build buses, in the late 1950s. I don’t think that the publicity surrounding Leyland’s later Hydracyclic recognized this earlier use of basically the same concept.

Daimler introduced its semi-automatic, with electric control under the “Daimatic” name in 1957, but in most cases as an alternative to, not a replacement for its well-established preselector models.

Guy followed in 1958, with electric control, without a brand name, and in this case replacing the previous preselector options.

Evidently each builder tended to make its own variations, which is why Leyland replaced the several heritage designs with the “Rationalized Pneumocyclic” in the late 1960s.

SCG had also licensed other OEMs to build the epicyclic gearbox. FBW in Switzerland was an early user of the air-operated type; I don’t think that is was any later than AEC and Leyland in adopting it.




Cheers,

[Herbert]

I'm really enjoying these technical/historical contributions, RK215. Thanks!

As far as I know, the Tiger Cub PSUC1 ... had the direct air pedestal type shift as standard when the Pneumocyclic was fitted ... However, there were variations, presumably according to customer requirements.

This is the case for the Perth MTT's 120 Tiger Cubs - they were all electric shift. The prototype was PSUC1/11, modified to PSUC1/13 before entering service. The remainder were PSUC1/13. There were a handful of other Tiger Cubs around WA with private operators which were synchromesh.

The WA Government Railways Road Services had one Tiger Cub and a few (I think) Royal Tiger Cubs. I'm not sure what gearboxes these had (Dennis96 are you following this?? !). They also had the largest fleet of PSR1/1 Lions outside of Baghdad, which were electric shift (one of which is in preservation; another is for sale down the road from me).

[boronia]

I think the pneumo-cyclic pedestal used a number of air lines connected to the gearbox to effect changes. I imagine this would be a higher maintenance system than a few electric wires, esp in rear engine/transmission vehicles; hence its unpopularity.


Leyland offered the p-c system in its trucks too. The NSW Fire Brigades got a LAD cabbed Chieftan fitted with it in the early 70s, however after too many attempts at selecting low gears at too high a speed resulted in blown motors and gearboxes, they retrofitted it with a stick shift.

[Herbert]

Interesting comment, boronia about air-change reliability. I had heard the exact opposite. In fact, when the MTT had withdrawn their last air-change Worldmasters, they still had original spare gear-change pedastals they'd never needed to use!

[boronia]

Interesting comment, boronia about air-change reliability. I had heard the exact opposite. In fact, when the MTT had withdrawn their last air-change Worldmasters, they still had original spare gear-change pedastals they'd never needed to use!

I'm sure the pedestals themselves would not be a problem. It was just all those air lines, connections and valves which I could see causing problems, esp after a few years of heavy use, as contributing to the demise of the system.

[RK215]

I’ve heard it both ways on the pedestal vs electric shift issue. Leyland’s own view, at least in the 1970s, was that the pedestal was more reliable, which was why it was applied to the Victory II. (I heard that from the folks on the Leyland stand at the 1976 Earl’s Court Commercial Motor Show, so I think it was reasonably authentic.)

Looking at the matter from first principles, the pedestal version had the pneumatic valves inside the pedestal, with 5 (for a 4-speed) air lines back to the gearbox with its internal air cylinders. The electric version had all of the switchgear in the selector unit, electric cables back to the gearbox, which had externally mounted magnet valves to control the air flow to the internal air cylinders. I don’t think that one can impute a fundamental advantage either way – the devil will surely be in the detail.

Regarding truck applications, perhaps most prominent was Leyland’s two-pedal Beaver of the late 1960s. Originally this had the 5-speed Pneumocyclic and a two-speed axle, later the 10-speed splitter Pneumocyclic. Apparently both were a bit troublesome. I think that some of the AEC V8 Mandators had Pneumocyclics, as well.

The 10-speed splitter was also offered on the Leopard in the 1970s. I’m not sure, but I suspect that this option was in place of the two-speed axle option, which disappeared when the Maudslay ear axle replaced the original Leyland unit, which could accommodate an Eaton two-speed head.

The Perth Tiger Cub fleet always struck me as a curiosity, coming as it did near the end of the production life of this model, hitherto generally considered underpowered for city work. In contrast, the 470 and 505-engined AEC Reliances were considered (just) adequate where a lighter underfloor chassis was required. I wonder if Perth looked at the Panther Cub? At least that would have put the noise at the back. Not that I’ve ever heard a 400-engined Tiger Cub, but I imagine that they were quite noisy. The 400 engine in the Bedford VAL14 was very noisy.

The Perth fleet was probably quite large in the Tiger Cub world. Maybe one or two UK operators had more – Western Welsh was a big operator of the type, but probably not Pneumocyclic. In respect of manual transmissions, originally the Tiger Cub had the GB58 4-speed constant mesh gearbox from the OPD1 era, later replaced by the GB83 4-speed synchromesh unit. A heritage Albion 5-speed constant mesh unit (GB-number unknown to me, but probably the same as used on the Albion Aberdonian) was a later option; I would guess that it was superseded by the Albion-Leyland GB241 group gearbox.

Cheers,

[Herbert]

"All noise, no action" is probably the most apt description for a Perth Tiger Cub. Max speed of 60km/h if you were lucky. They also suffered from terrible body vibration, exacerbated because (if I recall rightly) to achieve a lower floor level, the floor was mounted directly on the chassis frames. A handful were modified with sound-proofing material in the saloon after driver complaints. At one stage, ear-plugs were issued to a driver when he was allocated a Tiger Cub.

[boronia]

Thanks for your knowledgable insights into the two systems, RK215.

It is fun trying to analyse and understand decisions made by engineers so long ago.

[mrobsessed]

I was in an ex Western Australian Government Railways Hino RC320P the other day and it was the first time I had seen the sequential gate pattern mentioned previously. The revs took forever to die in those things with a constant mesh box, I reckon they would have seen their fair share of flat changes.
I used to ride to school in an East Lancs bodied Panther Cub with a 4 speed "mono" and 2 speed diff. Not a speed machine by any means, but the most innovative vehicle in the fleet.
Does anybody know the recommended way of changing diff ratios in a vehicle equipped with a epicyclic and 2-speed diff? I always was curious how the mechanic (who was the relief driver on my school run) would pull it out of gear, pull the red button out and put it back in the same gear. He was the same bloke who tought me to put it into 2nd, then 1st before taking off to lessen the jerk when picking up gears.

[Herbert]

You're a tease, mrobsessed!

Firstly, who do you know who has an ex-WAGR Hino? Former fleet no & rego would be nice to know!

Secondly, where did you live when you caught the Panther Cub? I have access to some photos of some which were imported secondhand into the eastern states.

Classic Bus magazine runs a section called Blunderbus. Panther Cubs featured early on in the series.

[boronia]

Sydney's AEC monos had an "interlock" on the change console that required the driver to go from 4th to 3rd before selecting 2nd or 1st. I always assumed this was just a safety device to prevent accidental selection of 2nd, as the actual movement could be done so quickly as to have no operational effect on the box itself.

The later automonos (AEC and Leyland) did not have this feature.

[Herbert]

All Perth electric-shifts had the gate, too, and there are some funny stories told about practical jokes played on unsuspecting drivers. Also, the "life & twist" lock on a pneumo pedastal caught quite a few out as well.

[RK215]

It is fun trying to analyse and understand decisions made by engineers so long ago.

Indeed it is much fun, and in the case of Leyland, some of its choices are hard to fathom!

Cheers,

[RK215]

Classic Bus magazine runs a section called Blunderbus. Panther Cubs featured early on in the series.

Yes, I think that the Panther Cub was something of a blunderbus, and as such not alone in the Leyland “zoo”.

It was no doubt heir to all of the problems that bedeviled the Panther/Swift, including body-damaging flexing and marginal cooling capacity. On top of that it was underpowered, both in general terms and against the likely duties – city service - for a model of this type. Although it can be thought of as a rear-engined Tiger Cub, I understand that it was a bit heavier.

Leyland might have been “arm-twisted” into this one by UK customers (e.g. Manchester) who wanted a short (33 ft) Panther, but still with the 7 ft front overhang. Under the then-applicable UK Construction & Use Regulations, Leyland couldn’t “get there from here” whilst retaining the 600/680 engine. Thus it was forced to use the 400, too small though it may have been. It is said to have pondered turbocharging the 400 for this application, which can be seen as indirect acknowledgement of the underlying problem. Leyland had something of a gap in its engine range between the 370/400 and 600/680. In retrospect one can wonder why it did not perhaps endeavour to bring the AEC 471/505 up to traditional Leyland standards, instead of pursuing the “fixed-head” 500 (aka “headless wonder”).

The Swift 505 was also offered in short (16 ft 6 in wheelbase, 33 ft nominal overall) as well as standard (18 ft 6 in wheelbase, 36 ft nominal overall) versions, so the 505 did fit the short chassis.

Before the Panther Cub, there was evidence that Leyland saw its smaller engine (350/375 and 370/400 family) as being unsuitable for the longer buses. The original Tiger Cub had a 16 ft 2 in wheelbase for 30 ft nominal overall, perhaps around 32 ft in later years. When the UK regs changed in 1961 to allow 36 ft buses, Leyland did not release a longer Tiger Cub, rather its entry was the 600-powered PSU3 Leopard. On the other hand AEC offered two 36-footers, the 4MU Reliance 470 and the 2U Reliance 590. Even earlier, AEC had introduced a 17 ft 6 in wheelbase, 33 ft nominal overall export Reliance (HMU and 2HMU), but Leyland did not respond with a similar Tiger Cub. (Arguably the Royal Tiger Cub filled this gap, but that had the 600 engine.)

Against that background, coupled with a trend to higher power-to-weight ratios, it’s a bit strange that the Tiger Cub was replaced, if indirectly so, with the Bristol LH, which was available in a long (36 ft) variant. It had the 400 engine, later the 401, and for the first couple of years or so, the Perkins H6.354 was an option.

Other Leyland blunderbuses of the 1960s were the Lion PSR1 and the Lowlander LR. I don’t think that there was anything particularly wrong with the Lion, which was a marriage of Atlantean and Worldmaster, it just lacked an obvious market. It looked like a case of “we’ll build it because we can”. It does have the distinction of being the first Leyland bus chassis to be fitted with a PowerPlus engine.

Leyland had to be coerced into building the Lowlander, and although it is widely “hailed” as a failure, I don’t think that AEC did any better, sales-wise with its broadly similar Renown.

In the late 1950s, the short-lived Albion Aberdonian, which was a Leyland-era product, was a borderline blunderbus. Effectively a lighter Tiger Cub, although in actuality a “stretched” Nimbus with 6-cylinder engine, it did not have a significant market. It seems that potential customers who were also heavier underfloor model operators had little need for it, whilst those who were not were wary of it. No doubt the latter preferred the later Viking VK41L, which was something of a delayed replacement model.

On the other hand, the original Leopard L, conceived as a Tiger Cub special, and, unlike the Lion, released without fanfare, must have been a pleasant surprise in sales terms. Although that said, I think it was the 1961 36 ft PSU3 version that “made” the Leopard. Despite the common naming, there were some differences between the L and the PSU3. In fact, the evolutionary pathway from the L to the PSU3 was via the Royal Tiger Cub RTC1 of 1960. Effectively the PSU3 was a longer RTC1, with the heavy duty suspension (for 13 tons gvw) optional not standard. An oddity of the L, which in 1966 was replaced by the PSU4 (“short PSU3), was that it did not have a Pneumocyclic option.

That it led to the PSU3 might be the RTC1’s main claim to fame. It was released quietly a bit before the Lion PSR1, and was not usually included in Leyland’s catalogues of the era. It missed out on being a significant player in any of the Australasian city fleets. Still, one can wonder if Sydney’s Leopard design, a modified PSU3, could equally have been described as a modified Royal Tiger Cub RTC1.

Cheers,

[Rail Bus]

Does anybody know the recommended way of changing diff ratios in a vehicle equipped with a epicyclic and 2-speed diff? I always was curious how the mechanic (who was the relief driver on my school run) would pull it out of gear, pull the red button out and put it back in the same gear. He was the same bloke who tought me to put it into 2nd, then 1st before taking off to lessen the jerk when picking up gears.

There is finaly something the famous Mr Obsessed doesn't know!

I have driven Mosman Is's ex UTA Leopard 3842 a number of times while it had a 2-speed diff in it, along with the standard 4-speed pneumo. The way I was taught to drive that was to change ratios "Under Load" then lift your foot off the accelerator to allow the ratios in the diff to change, then put your foot down again. This is exactly how I drive anything with a 2-speed diff, including an old Hino truck I have to put up with from time to time. Whilst it has a manual box, the principals are the same, diff-ratio-changing-wise as per the pneumo. It is not a hard concept to get used to. The only thing I do in the truck, is if I wish to change ratios running down a hill in gear, but not powering, I will dip the clutch slightly to allow the ratios to change smoothly. In a Leopard, for example, I would drop the gear breifly, then take it up again.

The 2-speed diff is a great help to drivers, but if not handled correctly, like anything mechanical, it can be damaged.

[Herbert]

I think I have seen reference elsewhere to Sydney's prototype Leopard having a chassis no in the Royal Tiger Cub series.

It is strange that Perth's Leopards didn't get a unique code. They were PSU3A/2R, which I think is the same as Sydneys. However, before they could be licenced, the Perth ones had to have their engines moved to satisfy the then-current axle load limits in place in WA. Consequently, I grew up thinking all Leopards sounded like the Perth variety. I clearly remember my first visit to Sydney in 1989, standing on a city corner watching a Leopard pass by, and being gob-smacked because, to my Perth-bred ears, it didn't sound like a Leopard!

Perth Leopards also different from Sydney's in having electric-shift.

Although small by Sydney standards, the Perth fleet has always seemed to be characterised by its own particular quirks (another example being rear-radiatored Panthers in arguably the hottest city in Australia!) - plus, until the O305s, a distinctly English (and particularly BET from the mid-1960s) influence in body design.

[Rail Bus]

I think I have seen reference elsewhere to Sydney's prototype Leopard having a chassis no in the Royal Tiger Cub series.

It is strange that Perth's Leopards didn't get a unique code. They were PSU3A/2R, which I think is the same as Sydneys. However, before they could be licenced, the Perth ones had to have their engines moved to satisfy the then-current axle load limits in place in WA. Consequently, I grew up thinking all Leopards sounded like the Perth variety. I clearly remember my first visit to Sydney in 1989, standing on a city corner watching a Leopard pass by, and being gob-smacked because, to my Perth-bred ears, it didn't sound like a Leopard!

Perth Leopards also different from Sydney's in having electric-shift.

Although small by Sydney standards, the Perth fleet has always seemed to be characterised by its own particular quirks (another example being rear-radiatored Panthers in arguably the hottest city in Australia!) - plus, until the O305s, a distinctly English (and particularly BET from the mid-1960s) influence in body design.

You are right about the chassis number for 3520 "Mr Whippy" being in the Tiger Cub series, although I don't know anything more on that. Perth was not alone in having its Leopards with electric gear changes: most private Leopards had/have an electric gear change. The thing of air-lines becoming a large scale problem is somewhat news to me. Although they run all the way up the chassis, the only problem I have experienced is either the braided line at the compressor, or a small, removable line somewhere along the chassis. I don't know off the top of my head where that is as I have never dealt with it myself.