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Disco/deffy axles.


dr pepper

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I'm sure there are others that have done this, however I've been working on fitting coiler axles to my series, heres some progress.

Since I took these photos I have just about completed the rear axle, and it will be going on over the next couple of days, I have some other pics of bashing and welding the axle, I'll post these when I get a lead for mi new fone, seems nokia have changed usb connectors again, and you dont get one in the box.

With mi new inclinometer gizmo I've been measuring up the series salisbury rear axle, with the spring mounts level, the diff nose is 2 degrees up (the spring must cause the diff to point nose down, as this would compensate for 'windup'), the shocker mounts are at 36 degrees forward, I've ground these off carefully and I'm gonna weld them on the disco axle, the spring centres are 35 1/4", and the shocker centres are 35 1/2", the diff drive flange on the disco axle is 1 3/4" further back than the salisbury so I'll need a longer prop, or a spacer-eek!.

I have new !part spring mounts for the disco, as said I'm gonna drill a 16.5mm hole for the leaf locater and weld them on upside down for the spring mounts.

Think that'll sort out the rear, dunno if I'm gonna need arches yet or not.

Heres some pics of bashings and measuring with the salisbury:

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Interesting story Nick and nice page.

How did you go about correcting the diff nose angle, or are you leaving it as is.

Spring perches for the disco are available from dare I say britpart, with 40mm lift, I got a pair of these with the vision of adapting them for the series mounts, time saver.

Phil. are you aware that I have a 109?, does the 2a 109 have a rover diff?, if so then thats a good idea.

I have been welding bits on the rear axle, its nearly ready to go in, new disco coil spring mounts with a 17mm hole drilled in the middle have been welded on for the spring perches, and the shocker mounts of the salisbury have been ground off and welded on.

Heres some more piccies:

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Picture_0103.jpg

Picture_0113.jpg

Picture_0124.jpg

Picture_0093.jpg

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Interesting story Nick and nice page.

How did you go about correcting the diff nose angle, or are you leaving it as is.

Spring perches for the disco are available from dare I say britpart, with 40mm lift, I got a pair of these with the vision of adapting them for the series mounts, time saver.

Phil. are you aware that I have a 109?, does the 2a 109 have a rover diff?, if so then thats a good idea.

I have been welding bits on the rear axle, its nearly ready to go in, new disco coil spring mounts with a 17mm hole drilled in the middle have been welded on for the spring perches, and the shocker mounts of the salisbury have been ground off and welded on.

Heres some more piccies:

Picture_0132.jpg

Picture_0103.jpg

Picture_0113.jpg

Picture_0124.jpg

Picture_0093.jpg

I twigged that it was a 109 from the fact that a Salisbury had come out and the pics showed it to be unmodified for 88" fitment. Yes a S2a 109" did have a chocolate rover diff at the back, in fact i changed my S2a 109" rear axle to a very late 1983 Salisbury.

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Interesting story Nick and nice page.

How did you go about correcting the diff nose angle, or are you leaving it as is.

Spring perches for the disco are available from dare I say britpart, with 40mm lift, I got a pair of these with the vision of adapting them for the series mounts, time saver.

I have been welding bits on the rear axle, its nearly ready to go in, new disco coil spring mounts with a 17mm hole drilled in the middle have been welded on for the spring perches, and the shocker mounts of the salisbury have been ground off and welded on.

I am using the same diff axis (+2 degrees as you said) on the rear axle. My suspicion is that the springs' axis is out of parallel with the chassis and transmission axis by that amount, with the shackle end of the springs slightly higher than the front end, but I haven't bothered to measure it - both of my SIII axles had the same 2 degree variance, so I merely copied it, having taken the spring saddles from one of those axles (which has already been robbed by the previous owner for its brake assemblies).

As for the front axle, I have copied the 1 degree variance between the swivel axis and spring mounts (the spring mounts sit at 2 degrees from horizontal, but you need the mating faces of the swivel pins to be at 3 degrees). The diff axis will be as it was when fitted to its Discovery donor, and I will merely reset the prop shaft's slip joint alignment to mimic the UJ yolk alignment on the coiler models to avoid prop shaft vibration from UJ flanges running out of parallel. Given that the 4wd system is only used at relatively low speeds, there should be no significant vibration from this solution, but if there is, I will ask Bailey Morris (a local prop shaft manufacturer who supply custom props as well as supply vehicle manufacturers) if they could calculate the exact amount of rotational offset the UJs require for the specific deflections my UJs operate at. The bump stops of the front axle need to be completely removed and refitted 5 degrees off the spring saddles, just like the Series axle - coiler axles have their bump stops on a forward slope to account for the axle's rotation around the rear the radius arm joint as it travels upwards, while leafers' axles maintain their axis.

Make sure the ends of those coil mounts you have used as saddles get plated up (5mm thick or more) to prevent them from collapsing sideways.

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Couple of things there, the vehicle doesnt spend long periods in 4wd yes, however the front prop will be turning all the time, I spose if there no load then vibration isnt going to be an issue, I am also considering fitting a r380 so the diff nose angle then would be more important, if I fit the r380 then I'll make the diff nose angle the same as the series.

About the plating yes I was wondering about that, however if you look at the 40mm lift brackets I have that are commercial items for the disco, they are only 6 mil and open front and rear, and on the disco they take the whole weight of the vehicle, obviously they were deemed good enough my the maker.

I'm not going to reinforce the rears, as the assy looks plenty strong enough, and the saddle mount is inbetween the spring and the axle so theres little up/down force, only sideways and most of that will be held by the U bolts.

The front is simlar pretty much, however for the front some extra work is probably good as forces are greater and the rear axle comming loose would be bad but the front would be a disaster.

Interesting comment about the prop shaft calculations, going to look into that, sort of thing I'm into, I suspect however the chaps at the shop you mentioned probably go off a wall chart and experience, the latter being the hard to get and expensive bit.

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On the coiler the springs seats are only taking the direct downward spring load. On a Leaf spring application they are taking all the location loads as well.

What he said! ;)

On coil sprung axles, the lateral loads are carried by the A-frame (rear) or Panhard rod (front) and their associated brackets. On leaf sprung axles, the lateral loads are carried by the springs and saddles. Your saddles will fold sideways unless you brace them by plating the ends with 5mm+ steel.

That rear cross member looks a little tired!

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I do not wish to criticise, it looks like you've done a pretty good job so far, but I have to ask...

How come you've used a rear axle with drum brakes? Surely while you were swapping it would have been easier to get one from an earlier Discovery or Range Rover, then you would have had discs all-round and could have done away with the tiresome drums for good!

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You were right about the rear cross member its seen better days, a lot of that has been covered up by the fuel tank, which is now back on.

I'm gonna just see what the mot man writes on the ticket when it goes.

New crossmembers are not expensive, however whilst writhing about on the ground struggling with the tank I was thinking, this is gonna be hard to replace, anyone done this?

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You were right about the rear cross member its seen better days, a lot of that has been covered up by the fuel tank, which is now back on.

I'm gonna just see what the mot man writes on the ticket when it goes.

New crossmembers are not expensive, however whilst writhing about on the ground struggling with the tank I was thinking, this is gonna be hard to replace, anyone done this?

I'm sure I'm interpreting this comment differently from how you intended, because it comes across as an "out of sight, out of mind" approach where, as long as it doesn't get picked up on MoT, it's fine. That cross member is rotten, and these things are always worse than they appear as the box sections rot from inside. Not only does that cross member take all towing or rear recovery loads, it takes a lot of torsional chassis loads when the axle articulates, keeping the chassis straight, and is supporting your fuel tank. I'm sure I needn't illustrate what will happen if the fuel tank supporting mounts, in the worst corroded area, fail, allowing the back of a full tank to drop and make contact with the road while travelling at speed.

If you can weld, a rear cross member is not too bad a job. The only difficult part is welding the top of each chassis rail extension, which many people foolishly ignore because the tub floor is in the way. You can either remove the tub, lift its rear (roof off and front doors open) or just remove the tub floor, but those seams definitely need welding too.

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Its actually not as bad as it looks, I have taken it apart again and cleaned everything up.

That said it is worse for wear.

I have to disagree with the comments of easy though, this is a lwb, as far as I can tell a lwb rear x isnt available, the ones I've seen done use a swb which has different depth chassis rails, so you have to rejig everything about and weld in a section over the top to get things to fit well.

The tub floor unbolts so that makes things easy.

I had no intention of hiding things from the mot man, and mine knows landys well so would probably see it anyways.

The old fuel was petrol so that wouldnt be good with sparks made by the tank contacting the road, the new fuel is diesel, still dangerous but this time to the vehicles behind esp on a corner.

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ok, back to the topic of axle conversion. not wanting to put a negative point to what is already a good start to the conversion but id recommend bracing the spring seats to stop them folding up sideways. i only used 3mm steel to brace mine but then i did make the rest from flat bits of 6mm plate so it was probably already stronger than the spring seats you have used.

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The weld on mount is only a few mil above the axle tube, and the bracket is 6mm steel, the spring mounts on the chassis are going to fail way before the mounts on the rear axle.

Anyways its circumstantial for the moment, the landy has taken enough time and money, the old girl is going into storage until I decide what to do.

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