Converting Series 3 rear end into trailer - tech questions

[pfillery]

I planned to make a trailer to use behind my series 3 but I'm stuck as to how best to go about it. I want to try and keep the weight as low as I can for ease of manouvering but also a heavier trailer requires engineering, brakes and a roadworthy which lighter ones do not (under 750kg I believe).

First question - The framework. Do I use parts of the rear section of chassis as a trailer frame? How would this compare in weight to having a similar section made up out of decent steel box section? I'm pretty sure a chassis is relatively light (150or so KG all up) so figuring that there are already the fixings for attaching the tub, plus the suspension mounts are there, is this a viable option? This way I'd only be up for a draw bar and maybe some reinforcing rather than having to get the whole frame made up (I'm only a very average welder with a bottom end machine so not going to tackle this myself - maybe I would tack it all together and have a pro weld it properly)

Second question - suspension. Obviously don't need shockies and don't want full springs, if I remove most of the leaves from a set of series rear springs, will this work as trailer springs? I've seen some of the springs you can get for trailers and they seem very flimsy. Obviously this thought goes along with the using of the chassis as the spring mounts will be in the correct place.

If anyone has any tips or ideas feel free to chime in. It's only a basic project, not looking to do anything too fancy.

[goingbush]

Use the existing chassis, Just Chop the chassis off about inline of just in front of the bulkhead behind the seats.
I sheeted in a section across between the door jambs & makes a handy storage area.

Make an aframe drawbar from 100x50 x 4mm RHS
Use standard suspension AND Shock absorbers

you won't need brakes if the atm is under 750kg, which it will be. It will be plenty light to manoeuvre around.
Far better and MUCH easier and CHEAPER than making a whole trailer chassis & buying a trailer kit.

but you have brakes, i assume your using standard rear axle - makes sense, just get a hydraulic override coupling and you can then go over 750kg.

I took mine to VicRoads and got it registered no questions asked, just call them prior and say your making a home made trailer and you want a VIN , they will give you a number that you can stamp into your compliance plate. probably the same in QLD ?

Any old welder will do you don't need a transmig. if you not confident just tack it together Im sure you will find someone close by to help you out with the welding.

the trailer code is national, you can download it from vicroads.

[JDNSW]

As suggested, you can use the back end of the Landrover chassis. But if planning an unbraked trailer limited to 750kg, you are carrying around a lot of unnecessary weight that is coming off your payload, and the springs will be too stiff (Take a couple of leaves out), as the back end of a lwb Landrover was designed to carry a payload of 750kg plus part of the weight of three passengers, fuel, engine etc. At the very least I would use a Series 2/2a Rover rear axle, as you can remove the centre entirely, and it is a bolt in swap for the salisbury, except for the prop shaft, which you are not using. If you are not using brakes, ditch the brake drums and backing plate assemblies. If using the Rover springs, keep the shockers.

My feeling would be to make a chassis, but this will probably cost more and may tax your welding (and design) skills. Which way to go will depend on your situation.

John

[clubagreenie]

As said in the first response, cut in front of bulkhead. I made up the a frame by building a box section from plat plate in the same section size as the chassis at that point and taking it forward. Just made it long enough to fit a spare wheel on. Kept springs/shocks std and brakes on hyd overide. Pull the diff (unless you want to carry a spare) and weld a plug in to the axle caps.

[pfillery]

I had thought about keeping the diff but it is fitted with a diff lock and would probably be better removed for someone else to enjoy rather than cut up, plus I'd imagine the extra weight even from the empty housing would be a fair amount. I have a pair of rear hubs cut off the last diff I junked, I was going to go with an unbraked trailer with a straight tube axle, whether I take the spindles off the remnants of the rear diff and have them fitted to a tube or get 2 corresponding plates welded on to an axle that I can bolt my spindles onto, I have not decided yet.

The original idea with the springs was to lose a couple of leaves and rebuild them myself with a shorter bolt through the middle, maybe 3 or 4 of the 11 leaves should be sufficient, and lose the shockies (these are stuffed anyway).

Does anyone have photos of similar conversions that might give me ideas?

I will probably post progress pics as I do it, if it gets that far of course. A bit uncertain what to do with the front.

[JDNSW]

I would fit shockers if you use the Landrover springs. While most light trailers do not have shock absorbers they do have damping provided by, for example, sliding one end of the spring (I have also seen spring loaded clamps on the leaf packs to act as friction dampers). With the spring properly bushed both ends, it will bounce a lot, and you also need to think about what will limit the spring travel when bouncing.

John

[pfillery]

I wonder if one could use the existing landrover chassis number as a trailer vin? Probably not I'd imagine?

[isuzurover]

I had thought about keeping the diff but it is fitted with a diff lock and would probably be better removed for someone else to enjoy rather than cut up, plus I'd imagine the extra weight even from the empty housing would be a fair amount. I have a pair of rear hubs cut off the last diff I junked, I was going to go with an unbraked trailer with a straight tube axle, whether I take the spindles off the remnants of the rear diff and have them fitted to a tube or get 2 corresponding plates welded on to an axle that I can bolt my spindles onto, I have not decided yet.


IRC the QLD rules state that car/vehicle axles cannot be used as trailer axles. A bit silly, but there it is.

[pfillery]

IRC the QLD rules state that car/vehicle axles cannot be used as trailer axles. A bit silly, but there it is.

I was erring more towards making an axle that will fit the series wheels (you can get them with holden, ford or landcruiser hubs so will have to make rather than buy), I think I may take the dimensions in to a welding/fabrication place and have them make it up.

Although I believe that under 750kg there is no inspection process for home made trailers.

[pop058]

IRC the QLD rules state that car/vehicle axles cannot be used as trailer axles. A bit silly, but there it is.

I believe this is related to a spinning yoke out the front of the diff housing. I have seen axle assemblies used with the centre is removed and a blanking plate fitted.


I was erring more towards making an axle that will fit the series wheels (you can get them with holden, ford or landcruiser hubs so will have to make rather than buy), I think I may take the dimensions in to a welding/fabrication place and have them make it up.

Although I believe that under 750kg there is no inspection process for home made trailers.

correct. self assessment form required. Go to the RTA and get a VIN (and plate),tick and flick a few questions, fill in some dimensions and details and you have it. should not even have to present it to the RTA.

[pfillery]

So are there particular specs for Qld and where can these be found? I had heard that the axle had to be in the centre of the "box" part of the trailer, this is the reason a lot of tub to trailer conversions have a tool box on the front, and yet a lot of boat trailers have the wheels towards the back end.

Also what is the consensus on drawbars? One up the middle with some supports like the army trailers or an A frame? Are there any advantages to either system apart from amounts of work and steel required?

[pfillery]

And what are peoples suggestions regarding axles? There are a lot of ready made ones, but not designed to take landrover hubs. How solid or thick should an axle tube be? Are there any real differences between using a round and square tube for an axle?

[JDNSW]

So are there particular specs for Qld and where can these be found? I had heard that the axle had to be in the centre of the "box" part of the trailer, this is the reason a lot of tub to trailer conversions have a tool box on the front, and yet a lot of boat trailers have the wheels towards the back end.

Also what is the consensus on drawbars? One up the middle with some supports like the army trailers or an A frame? Are there any advantages to either system apart from amounts of work and steel required?

The national trailer design specs call for the wheels on box trailers to be not further forward than the centre of the box - hence the tool boxes in front, these are counted as part of the box. The idea of this is to ensure that the towbar always has positive download. Boat trailers can often have the wheels well towards the back without excessive download for two reasons - the boat often overhangs the rear of the trailer, and if the boat is an outboard one, its centre of gravity is well back due to the heavy motor.

For a light trailer, I would only use an A frame, as this will give the best strength/weight ratio. However unless you are really trying to reduce weight, the difference will not be all that significant.

John

[JDNSW]

And what are peoples suggestions regarding axles? There are a lot of ready made ones, but not designed to take landrover hubs. How solid or thick should an axle tube be? Are there any real differences between using a round and square tube for an axle?

I have seen suggestions that fabricated axles are not accepted, but I have yet to find anything confirming this.

A larger diameter tubular axle will be lighter than a solid one of the same strength.

There is no practical difference between square and round axles, whether solid or tubular, except possibly that round rather than square U-bolts will be stronger.

Hubs to fit Landrover wheels are available (you'll probably have to get them ordered in), but not with the correct stud type - they are 5/8"UNF not 16mm or 9/16"BSF from memory.

[pfillery]

This was why I was contemplating having a plate welded to each end of an axle tube, the same distance apart as a diff with the hubs removed, onto which the wheel spindles from a series 3 could be bolted (so they can be replaced if needed) or welded if this is the requirement. Thus I can fit landrover hubs to it. I guess what I need to find is what wall thickness of tube is a minimum for strength, and then provide some specs to a proficient welder for fabrication (beyond my skills and I don't want to lose a wheel).

I feel that it would be less effort to start from scratch rather than try and modify an existing axle.


I have seen suggestions that fabricated axles are not accepted, but I have yet to find anything confirming this.

A larger diameter tubular axle will be lighter than a solid one of the same strength.

There is no practical difference between square and round axles, whether solid or tubular, except possibly that round rather than square U-bolts will be stronger.

Hubs to fit Landrover wheels are available (you'll probably have to get them ordered in), but not with the correct stud type - they are 5/8"UNF not 16mm or 9/16"BSF from memory.

[JDNSW]

This was why I was contemplating having a plate welded to each end of an axle tube, the same distance apart as a diff with the hubs removed, onto which the wheel spindles from a series 3 could be bolted (so they can be replaced if needed) or welded if this is the requirement. Thus I can fit landrover hubs to it. I guess what I need to find is what wall thickness of tube is a minimum for strength, and then provide some specs to a proficient welder for fabrication (beyond my skills and I don't want to lose a wheel).

I feel that it would be less effort to start from scratch rather than try and modify an existing axle.

If you are doing this, I would suggest a diameter the same as the axle housing - to match the flange to be bolted to the sub axles, and to use the standard U-bolts.

While it would be possible to calculate the wall thickness for the requires strength from the spring locations and the bending moment applied by the maximum load with a suitable factor for bumps and then a safety factor, I suggest that this will probably come up with such a thin wall that it will be excessively prone to damage from rocks etc. I would look at the wall thickness of the Rover axle housing - it need be no thicker than that, as the loading is less and has no torque to deal with. From memory that is about 2.5mm.

John

[pop058]

In simple terms, the "load area" in front of the axle centre is to be greater than (or equal too at the very least) the "load area" behind the axle. It is common to mount the axle 50mm back from centre to achieve this. Ute tub trailers usually include the toolbox on the drawbar aspart of the load area. This then complies with the "load area" regs

If you are not going to run brakes, then I advise keeping the tare wieght as low as possable. A standard 39mm solid (round or square) axle is rated at about 1000kg. A 45mm axle is about 1400/1500 kg. It would probably be cheaper, simpler and lighter to run a normal trailer axle as supplied by most trailer shops. Landy hubs are not that hard to come by, but as stated, they may just be an order-in thing. The A-frame drawbar would be the best option for strength versus weight unless you are chasing the particular "look" of a military trailer.

link for National guidelines

Vehicle Standards Bulletin VSB1 (http://www.infrastructure.gov.au/roads/vehicle_regulation/bulletin/vsb1/index.aspx)

HTH

[Slunnie]

Just check the shape of the chassis and the cross sectional shape of the chassis also. It potentially may not be very good for attaching the drawbar with a decent seperation between the front welds and the rear welds, the drawbar height or a good flat surface for making the actual weld. Then again, it may be ok, but the seam is in a funny place for what is essentially RHS.

For the axles, 39mm round is the lightest, 40mm square is next strongest and then 45mm square. If its only being rated to 750kg then the round axle will be ok, considering its being built for 4WDing then I'd use the 40 or preferably 45mm square. Also slimline bearings. You can get LandRover stud pattern hubs off the shelf - see an Alko retailer. I would remove the entire factory axle and keep it complete, save the weight and use a manufactured trailer axle that is 1/4 the weight and wont drag. You can also set the track if you want it wider than a regular narrow series setup - or keep it the same. The axle, about 50-75mm rearward of the box's centreline - the aesthetics may not work.

For the drawbar, for that load rating we use typically 75x50x4 and create an A-frame. I wouldn't use a single drawbar, there is too much stress that is generated across the drawbar and it will probably crack or bend. The Mil do it with a massive section and very short trailer, but you're conditions are not the same. Dont weld across the top or bottom plates of the drawbar anywhere except at the coupling plate and you will need to work out how you're going to put a satisfactory front cross member in to the chassis so that you can attach the drawbar to that.

As suggested, I would also pull leaves out of the spring pack, but I wouldn't bother resetting them. There is too much load carrying capacity as a fully laden 4WD let alone as a light box trailer. It also sounded like you or someone was talking about trailer slipper springs, these don't sit on the chassis, the bear on a wear plate which is welded to the chassis. For 4WD applications they still use leaf springs with shackles - these are quite stiff for their load rating to handle the roughness. A trailer with the light 4WD springs, I can get onto one of them and jump around and they don't move much at all!

Shocks - for 4WD applications - yes.

[goingbush]

I have made heaps of trailers and if doing a Landrover trailer over again I'd still use the Rover Chassis / suspension / axle complete. All things considered your wasting your time & money by going any other path & you will have a much better trailer to boot. The standard body on a home made chassis won't cope with whatever weight gains your trying to save by going the other way. Infact I doubt you'll save much at all. Its no trouble to tow a trailer full to the top with screenings on a standard chassis. You just won't do that on a standard single axle.

Rather than use the full rover rear axle I usually just make a new axle from tube then weld flanges on the end & bolt LR or Toyota stubs to it

anyway whatever way you go there is some good trailer resource stuff here
http://www.spinnythings.com.au/pub/CATALOGUE.pdf

[Brad110]

I have built 3 with success. Travelled extensively well loaded.
80's Rangie with various tray. First 2 with alloy 1 ton tray and current extended 130 tub.
Overide brakes and diff centre removed and blanked off.
Weight 520kg with spare and tray, toolbox, original tank and support legs.

I did over 65k in the north and desert towing unit thru kimberlies, Arnhem land and cape with no problems.
Only difficulty is sorting correct springs. Id like to try airbags in springs. I am also going to retfofit a swaybrace.

Its the cheapest way to build a trailer with the best suspension around and LR stud pattern and disc brakes.

[JDNSW]

..... Its no trouble to tow a trailer full to the top with screenings on a standard chassis. You just won't do that on a standard single axle.
......

Or legally on any unbraked trailer! (and probably not on a braked single axle trailer based on a Landrover either)

John

[Blknight.aus]

I had thought about keeping the diff but it is fitted with a diff lock and would probably be better removed for someone else to enjoy rather than cut up, plus I'd imagine the extra weight even from the empty housing would be a fair amount. I have a pair of rear hubs cut off the last diff I junked, I was going to go with an unbraked trailer with a straight tube axle, whether I take the spindles off the remnants of the rear diff and have them fitted to a tube or get 2 corresponding plates welded on to an axle that I can bolt my spindles onto, I have not decided yet.

The original idea with the springs was to lose a couple of leaves and rebuild them myself with a shorter bolt through the middle, maybe 3 or 4 of the 11 leaves should be sufficient, and lose the shockies (these are stuffed anyway).

Does anyone have photos of similar conversions that might give me ideas?

I will probably post progress pics as I do it, if it gets that far of course. A bit uncertain what to do with the front.


Ive got a thread on here somewhere thats got a copy of the chassis layout and where I cut/fold them.

[Blknight.aus]

http://www.aulro.com/afvb/trailers-vans-campers/31251-swb-siii-becomes-trailer.html

[pfillery]

So is there any truth to what someone told me that you can't use a hollow axle and have to use a solid one? I thought most axles on trailers were hollow, I can imagine how heavy a 40mm square axle would be if it was solid. Someone has suggested that a hollow axle would be illegal but there appears to be nothing to back this up in the ADRs. Any thoughts? After all a diff housing is hollow. Most old boat trailers have hollow tube axles. I found a really solid piece of galvanised tube (old water drainage pipe actually) with a 4mm+ wall thickness and about the same size as the diff tube - pretty heavy and very solid. Hopefully should suit.

[pop058]

your standard 40/45 mm round/square axles are solid. You can readily buy just stub axles to weld into a suitable tube, so hollow axles are not illegal. The onus is on the manufacturer (owner/builder in your case) to ensure things are adequate and safe.

[Blknight.aus]

the only ones I know of to be a tube rather than the bar are the ones with the mounting flanges welded on and those are a rather thick tube.

If you know a good welder you can adapt the mounts from a rover axle (as opposed to a sals) onto an axle, if you want to go for a hydraulic discs on the rear let me know as I'll be stripping the back end of a disco 1 in the next few weeks.

(check your PM's)

[Alex 110]

I'm doing a similar trailer build - using the chassis, suspension & axle off a discovery 1 with a series tub mounted on top.
Retaining the triple link suspension & full axle with the diff centre removed & blanked.
Here in NSW a home built trailer requires a weighbridge certificate and blueslip inspection before it can be rego'd.
Only a coat or 2 of paint & it will be finished, but its been like that for nearly a year:o Where does all that time go??
I'll post pix once its done (hopefully not another year:D)

[Tank]

I'm doing a similar trailer build - using the chassis, suspension & axle off a discovery 1 with a series tub mounted on top.
Retaining the triple link suspension & full axle with the diff centre removed & blanked.
Here in NSW a home built trailer requires a weighbridge certificate and blueslip inspection before it can be rego'd.
Only a coat or 2 of paint & it will be finished, but its been like that for nearly a year:o Where does all that time go??
I'll post pix once its done (hopefully not another year:D)
To qualify for the cheap rego ($52) and no yearly inspection in NSW the trailer must weigh 250kg or less, a landrover ute body and chassis will be well over that amount, so no chance of cheap rego or no yearly pink slips, Regards Frank.

[Alex 110]

To qualify for the cheap rego ($52) and no yearly inspection in NSW the trailer must weigh 250kg or less, a landrover ute body and chassis will be well over that amount, so no chance of cheap rego or no yearly pink slips, Regards Frank.

Thanks Frank - I recently became aware of this, & as a result I'm going to refit the calipers, put overrun brakes on it & register it as heavy as I can with a single axle.:D

[JDNSW]

To qualify for the cheap rego ($52) and no yearly inspection in NSW the trailer must weigh 250kg or less, a landrover ute body and chassis will be well over that amount, so no chance of cheap rego or no yearly pink slips, Regards Frank.

But should be quite feasible with a chassis made only as strong as it needs to be plus the ute body.

John

[p38arover]

But should be quite feasible with a chassis made only as strong as it needs to be plus the ute body.

Build it as light as possible, get it weighed and registered and then add any extra strengthening, brakes, etc? :angel:

[bobslandies]

Build it as light as possible, get it weighed and registered and then add any extra strengthening, brakes, etc? :angel:

You will find that any trailer registered to carry over a certain weight (750Kg) will require brakes and if so also needs the yearly pink slip inspection irrespective of whether it weighs less than 254Kg. There are a couple of exceptions but you are unlikely to succeed in having them apply these days.

Over-run brakes are not accepted for trailers where the Aggregate Trailer Mass (ATM) is over 2000Kg. Over 200Kg there must be brakes operating on ALL wheels if it has more than one axle.

All trailers registered after 1 January 1981 and required to be fitted with brakes are also required to be fitted with a Parking brake. The use of hydraulic operated over-ride brakes incorporating a parking device are apparently no longer acceptable as it is possible that the hydaulic pressure may be lost and the trailer "parking" brake assembly will not safely stop the trailer from moving when parked. (NSW determination at least)

Bob

[lebanon]

I have used the chassis and differential case on a SIII, We use the trailer regularly, we also used it on a 500 KM trip Jordan with a great part through the desert carrying 3 drums full of water and fuel. The trailer gave no problem at all, it was easy to maneuver with.

I am actually working on transforming it into a camper trailer.

As you can see in the attached picture I have bent the two chassis frames to form an A frame that was strengthen by welding to metal plates to increase the rigidity of the front end.
The hitch was then bolted to the frame through the plates. This setup levels the trailer with the 110.

I hope the pictures gives an idea.

https://www.aulro.com/afvb/images/imported/2012/05/316.jpg

https://www.aulro.com/afvb/images/imported/2012/05/317.jpg

[Hoges]

Thank you for offering a glimpse of another part of the Land Rover world... That's a REAL expedition :BigThumb: I presume your mates are the "Roadside Assist" service:D Was that diesel or petrol in the fuel drums?

Never ceases to amaze me that while there are problems aplenty in that part of the world, Land Rover enthusiasts are still out there going about their business...perhaps we should have the Land Rover Peace Initiative:eek::angel:
cheers

[lebanon]

Thank you for offering a glimpse of another part of the Land Rover world... That's a REAL expedition :BigThumb: I presume your mates are the "Roadside Assist" service:D Was that diesel or petrol in the fuel drums?

Never ceases to amaze me that while there are problems aplenty in that part of the world, Land Rover enthusiasts are still out there going about their business...perhaps we should have the Land Rover Peace Initiative:eek::angel:
cheers

We were caught in a "Djin" or dust devil when we were securing the barrels. The green barrels had water in them while the third had petrol.

I guess that most of the Land Rover enthusiasts will adhere to the Land Rover Peace Initiative.

By the way it is now very insecure if not to say impossible to travel from Lebanon to Jordan because of the problems you mention.

[jamdadbay]

bump .... So does anyone have any pics of their converted trailers? Either pics of the works in progress our completed would be great.

Sent from my XOOM 2 using AULRO mobile app

[Goenin]

I have a tub and canvas canopy with fram all genuine Landrover if any one wants.

[numpty]

http://www.aulro.com/afvb/trailers-vans-campers/168752-my-trailer-build-rebuild.html

My work in progress

[Goenin]

That's fantastic. Love ya work.

[twitchy]

Will post some later when I'm on the pc.