Newbie: Disco 6x6 from Spain

[tacr2man]

If you need 6x6 with a close coupled rear end why not just use a unpowered axle , and fit overall tracks on the rear when you need the extra drive and flotation , which is usually only in slow speed situations . Scammel and leyland used the overall track system , although they were both on walking beam double drive rear ends , one chain drive the other gear drive. There was a ferguson tractor that IIRC was used in artic exploration that used tracks that went over the large rear wheel and round a smaller jockey wheel , you would of course need a tensioner arrangement to take up slack in certain articulations

[Ex Member]

I haven't really delved into hydraulics much. I was discouraged years ago when I looked at the complexity of plumbing and the size of the oil reservoir required to keep the LandRover Mayflower winch operating efficiently. And I would have thought a diff mounted hydraulic motor would work harder and require additional oil capacity and cooling requirements than a low geared winch.

It should not be hard. You would not need a large reservoir. Just a suitable cooler. I think control would be easy to achieve. Proper matching of the pump and motor would solve most of it and the pump speed would match the engine driven wheel speed with a PTO pump. The PTO pump system is available off the shelf.

[Ex Member]

The best way forward and backwards too

Hydraulics are amazing especially hydro-static transmissions, now if the final drive from the back axle could be monitored by some means,possibly an ABS sensor then a second sensor on the middle axle it is entirely possible for an ECU controlled hydro stat to actually maintain ground speed in terms of wheel speed between the two axes but any type of cross axle situation unless transverse diffs were applied might see the back axle either dragging or digging holes.

Unless someone who knows more on hydraulics wants to come and educate us I like th idea of it but just not sure exactly how to make it work as there are numerous ground speeds that can be covered and not just in low 1 or 2 , on the subject of cooling the hydraulic system could have it's own cooler system as many of the hydrostat wheeled loaders do, normally oil to water through the radiator then to atmos via the heat exchange of the water and radiator.

Are the through drives even available any more? Despite the huge cost...

The idea is the pump is driven from the PTO. The pump flow rate is then proportion to the gear box output and this the wheel speed. A hydraulic motor would then run at the same proportional speed with the spool valves fully open. It might as simple as linking a spool valve to the throttle or it may be possible no control is really needed.

[bill van snorkle]

Are the through drives even available any more? Despite the huge cost...

I would assume if Foley Special Vehicles still convert some LandRovers to 6x6 then they would still be available. Anyone with a lathe and mill should be able to make their own from old transfercase bits very much cheaper.

[Ex Member]

http://forum.lro.com/viewtopic.php?f=18&t=89595

Has any one seen this through drive?

edit: Same one here as well: http://www.aulro.com/afvb/projects-tutorials/138005-ikea-6x6d-anyone-have-allen-key.html I assume that is the same Bill commenting there... Post 108 shows the diff apart. Basically part of a transfer case on the front with a shaft through the case to the rear.

[CwazyWabbit]

Also Tonks4x4 posted it here http://forums.lr4x4.com/index.php?showtopic=78404&p=675836

Maybe he will comment on this thread?

[Ex Member]

The front looks like a chain driven transfer case with vacuum disconnect. The chain driving the middle axle.

[Ex Member]

Here are the Ford 9" through drives you can purchase, http://www.differentialeng.com/NineInchTandems.htm If you have money, it would seem better spent on that route than farting around with the Rover axles.

[Nigelw]

Here are the Ford 9" through drives you can purchase, http://www.differentialeng.com/NineInchTandems.htm If you have money, it would seem better spent on that route than farting around with the Rover axles.

From the looks of it that is probably something that could be modified into rover axle casings should you wish?

Yes there are a lot of bigger and better axle components out there but not always the money to spend on bespoke machining and engineering to bring them to life.

In all honesty, there is adsolutely nothing to be gained in our circles of mainly rugged terrain off roading that a vehicle large enough to be 6x6 would adequately cope with, now in the overlanding type of driving where possible heavy loads combined with tough terrain where there would be no such complications with the length and higher(potentially?) turning circle it would be ideal.

But I keep wondering why keep on with the complicated task of making beam axles flexible? For me I think independent suspension systems where an almost static gearbox where the drive line comes in and can be split fore and aft is better, I do see the want to ke within some sort of originality but I see no point to attempting to create highly flexible suspension system on such a vehicle, a rear steer system to alleviate tyre scrub certainly!

[Soren Frimodt]

Though it doesn't look like you can disconnect the drive on that 9". Very simple system to do if you know someone who can make you a new pinion. But I would think you'd prefer to be able to disconnect it, my brother has a REO 6x6 (the one with the rockwells) and it is permanently engaged between the rear axles. On tarmac this really hinders his turning and your can hear it squealing trying to loose grip.

[Team Idris]

"Matt lee tried it with a comp safari buggy, having a motor in the front wheels, only to be selected if the going got tough. He didn't preceed with it, I believe due to it running too hot."

For comping you'd want auto locking front hubs to go with hydraulic motors, just to stop the drag and then to reduce heat.

[bill van snorkle]

From the looks of it that is probably something that could be modified into rover axle casings should you wish?

Yes there are a lot of bigger and better axle components out there but not always the money to spend on bespoke machining and engineering to bring them to life.

In all honesty, there is adsolutely nothing to be gained in our circles of mainly rugged terrain off roading that a vehicle large enough to be 6x6 would adequately cope with, now in the overlanding type of driving where possible heavy loads combined with tough terrain where there would be no such complications with the length and higher(potentially?) turning circle it would be ideal.

But I keep wondering why keep on with the complicated task of making beam axles flexible? For me I think independent suspension systems where an almost static gearbox where the drive line comes in and can be split fore and aft is better, I do see the want to ke within some sort of originality but I see no point to attempting to create highly flexible suspension system on such a vehicle, a rear steer system to alleviate tyre scrub certainly!

Any form of reasonably designed axle design/suspension arrangement is suitable for LwB overland camper style vehicles, because it is highly unlikely that a vehicle such as that would be expected to cope with Darien Gap style terrain.But for true extreme terrain the PinzGauer 6x6 IMO and my experience is just one perfect example of how not to design a suspension system. As I mentioned on previous posts, absolute maximum interaxle articulation is important to avoid the scenario where the mass of an air borne rearmost axle assembly plus the load it carries becomes a counterweight that unloads the vehicles front axle, or the air borne foremost bogie axle from greatly increasing the ground pressure on the rearmost tyres causing them to bury themselves in soft terrain. The video of the converted LandRover 101 6x6 camper earlier in this thread is a good example of what I am describing.Yes it does have beam axles, but a very poor rear suspension arrangement.

The thrudrive axle that Red 90 linked to I believe is from the LandRover Company's Special Vehicles Division and contains an interaxle differential to prevent wind up between the bogie axles.

[TD Man]

Bump...

Hi all, i have been around for a wile but not up to much on here, but... I now have a 110 to convert to a 6x6 and this is the time to sort out the design as I will need to get my paper work under way for the certification process.

I am looking for any and all advice and comment. I will post the details of the build soon but as its 00:20 atm and I'm of to get some much needed shut eye.

TDman

[o_teunico]

Hi TDman!

I'm with the smartphone now, but at night I will have access to a laptop and I will post some pictures of Bill's drop boxes that he has sent via FB.

What design have you been thinking for your 6x6?

[o_teunico]

Bill´s famous drop box.

[o_teunico]

Just some questions for Bill,

Why so much holes in the casing´s lip?

The gear that goes in the diff´s pinion, needs to be modificated or just by coincidence the have the same splines?

How is the box´s casing joined to the diff´s casing? Welding?

[bill van snorkle]

Just some questions for Bill,

Why so much holes in the casing´s lip?

The gear that goes in the diff´s pinion, needs to be modificated or just by coincidence the have the same splines?

How is the box´s casing joined to the diff´s casing? Welding?

All the holes were my pointless attempt at lightening the box, so I came to my senses eventually and stopped drilling them.

The gear on the pinion shaft was bored out and the pinion flange was turned in a lathe to press in and welded to the gear.

Series diffs have a bolt on pinion seal housing fasted by 6 5/16'' bolts I drilled and retapped the bolt holes out to 3/8" to bolt the dropbox on but there is an additional brace welded to the diff casting that bolts to the drop box for extra support.

If I were to re use the box I would space the taper roller bearings further apart on the intermediate gear because the thrust loads are greater than I originally imagined.

[TD Man]

Hi TDman!

I'm with the smartphone now, but at night I will have access to a laptop and I will post some pictures of Bill's drop boxes that he has sent via FB.

What design have you been thinking for your 6x6?

Hi Mate,

Thanks for the pics, I haven't seen that before, very interesting.

I am looking to use my 110 double cab and shorten the chassis to 100" wheelbase and then extend the rear chassis at the spring mount by about 41" to duplicate the rear suspension set-up, I will put the truck on air bags all round and interlink the rear 4 (as pairs on each side) to provide load sharing suspension.

I have a Leyland P76 v8 taken to 5.0 and on efi to power it and will run it on 37" rubber.

Then I can get it on the road and start to use it and see what else I can do, but just a bit at a time as I don't want to have "the best truck in the world" sitting in my drive be-cos its to big a job to finish.

In the long tern I would like to add portals, a pto winch, longer travel suspension, walking beams, a RR disesl V8 and a bunch of other stuff but slowly does it...

Do you have a 6x6?

I'm very interested in all things 6x6 and have access to a 6x6 chassis but not sure about the $16,000 price tag.

Bill, the bit I'm not sure about is the drive to the rear axle, is it better to through drive the first axle, or a 2bd shaft and if so were do you split the drive?

[FridgeFreezer]

If you want 6x6 with portals / walking beams, why not start with a 6x6 vehicle on portals, would save a hell of a lot of engineering that you'd then throw away later.

[Jamie_grieve]

I'd agree with fridge here, get a Volvo C304 if you need a six by six chassis with portal axles. It'll save a lot of time and trauma and would hold it's value better than developing another vehicle so similar.

I'd agree with Bill about a 6x6 not being as ultimately capable as a well developed 4x4 but I'd also add that compared to a 4x4 using a production chassis with standard type suspension then a 6x6 will outperform cross country in most circumstances except speed.

As Bill says, for a 6x6 to really perform it's important to have proper load sharing throughout the whole range of suspension travel. I'd suggest using oversized pipes between the bags to improve reaction time and to avoid one bag being at a higher pressure than the other on bump. That said, even with standard pipework they would be a lot better than coils in the same circumstance.

You could still use the existing land rover suspension but not have a walking beam but just employ a leaf spring in the conventional fashion. This would probably be the simplest and best performing method even above that of the air bags for serious cross country work but not as good for rough gravel tracks and pot holes.

One problem with walking beams other than their huge weight is also that the front wheel becomes unloaded climbing and they bounce and the opposite on braking. A good modern comparison would be a Moxy / Komatsu dumper with a walking beam versus a Volvo with a balance beam and A frames and panhards. The Volvo outperforms at speed and climbing, the Moxy will crawl through a bit of bad ground better.

I had a wee look for the 'Scammel constructor' Land Rover, it was amazing. Anyone got a link? It would be worth looking at.

[Nigelw]

I personally found the Volvo A, B & C series Dumpers superior in every way to the competition. The D, E & F sereis are comfy but lack power and ability of the predecessors, best ADT was volvo's C series hands down.

I keep thinking independent suspension would make for a better/easier conversion for some reason

[bill van snorkle]

Hi Mate,

Thanks for the pics, I haven't seen that before, very interesting.

Bill, the bit I'm not sure about is the drive to the rear axle, is it better to through drive the first axle, or a 2bd shaft and if so were do you split the drive?

Sam, pinion mounted throughdrives or drop boxes are a bit more difficult to do with Salisbury diffs, because the axle tubes really need to be removed so that the diff casting can be fitted in a lathe to face back the pinion bearing nose, weld a mounting flange to it, and machine true. Also due to the extra bulk of the Salisbury, larger diameter gears are required so that the output shaft to the rear diff will clear the Salisbury diff casting. The drop box pictured above uses transfercase gears from Series vehicles. To get the offset required to clear a Salisbury, I determined that mixing and matching gears from an LT95 transfercase would work. Morse Silent chain would also work, but tend to overheat and stretch over time. Considering that you plan a 100" primary wheelbase, probably the easiest way of getting twin rear output shafts would be to use an LT95 transmission with the special pto for powered trailers that is also fitted to the Australian army 6x6's.

[o_teunico]

Do you have a 6x6?

Yes, but it´s made from vapour and only exist in my mind!

[o_teunico]

.Series diffs have a bolt on pinion seal housing fasted by 6 5/16'' bolts I drilled and retapped the bolt holes out to 3/8" to bolt the dropbox on but there is an additional brace welded to the diff casting that bolts to the drop box for extra support.

Unfortunatelly I have no access to one of those. Even our SI LWB hearse has Series III style diffs, with no six bolt seal housing

[bill van snorkle]

Unfortunatelly I have no access to one of those. Even our SI LWB hearse has Series III style diffs, with no six bolt seal housing

Ashcroft and Sandringham weld the flanges on to the pinion housing to bolt their throughdrives onto. As per previous post,for anything over 90" wheelbase the LT95 method would be easiest and most efficient with less frictional losses.Those old pinion housings are 10 a penny wherever Landrovers were sold in any quantities.

I would agree with Jamie and John about just buying a 6x6 Volvo, except that Sam is in New Zealand, and if it's anything like Aus, importing and registering a left hand drive vehicle with no previous registration history here is fraught with legal headaches. Best just try to source the axles and fit them to a Landrover.