Leaf and coil sprung axle differences

[Bigj66]

Thanks for all the feedback and links to past information chaps. Lots to read and re-read and I’m still digesting it all but for the minute can I just check that I have understood some key points for now?

If it was possible, and I know it isn’t, to bolt a coil corner to a leaf axle casing, then the resultant track width would be narrower than the standard series axle width? 

With respect to the track control bar at the rear of the coiler axle, this will clash with the pinion of the diff, the leaf springs or both?

[Wytze]

This picture is from discomikey.  You can see the spacer, and it looks like he reused the series swivelarms.  

[Snagger]

12 hours ago, Wytze said:

I must say... Going that route myself, moving the track rod to the front on coiler swivels, and a high steer pitman arm.   Did the numbers, and  got two different numbers on the  top and bottem pin on the swivel.   Top is about 2 inches off, the bottem one less then half of a inch.   But...  Pushing around a non running 109 in original setup is very heavy when it's not in a straight line.  And with the new setup, i can push it around a corner with a lot more ease.  So, in my opinion the new situation on my 109 is better then original.    

And,  on a 88 and a 109 are the same axle's.. So, the one or the other must be way off, ackerman wise.  Just like the 90 , the 110 and 127.  All on the same front axle.  

You’ve missed the point.  You can’t move the track rod on a given axle from front to rear or rear to front without reversing the Ackerman angle.  You are right that LR didn’t optimise the angle for each wheelbase, as these are not precision handling sports cars, but reversed Ackerman is a very different thing that in my opinion is dangerous on a road going vehicle and should render it unroadworthy - it is forcing a tyre to skid every time you turn, and that is not acceptable on the road.  What it does for a vehicle only used on private land is entirely a matter for the owner.

If you can find a way to correct the Ackerman problem with track rods up front, then great, but I don’t think I can be a done without altering the brake system - a track rod in front of the axle needs to be longer than the distance between swivel pin midpoints.  How much depends on the length of the steering arms and wheel base (both are assumed by LR as one set value, and I’d wager they use 100” as the wheel base because these parts came from the RRC).  A track rod behind the axle should be shorter than the distance between track rods.

On series axles, you can see the rod is longer and how relatively close the ends are to the brake back plate.  On coiler axles, the arms are canted well inboard, and fitting bolt-on arms like the Series vehicles is limited by the position of the brake discs and shields - if you can move the brake disc out further and omit the shield, you may be able to restore correct Ackerman.  But is it worth all that trouble just to fit disc brakes, which would no longer be standard, if a kit like Zeus or Heystee is ready to go off the shelf, with their testing and certification?

[Bigj66]

2 hours ago, Snagger said:

You’ve missed the point.  You can’t move the track rod on a given axle from front to rear or rear to front without reversing the Ackerman angle.  You are right that LR didn’t optimise the angle for each wheelbase, as these are not precision handling sports cars, but reversed Ackerman is a very different thing that in my opinion is dangerous on a road going vehicle and should render it unroadworthy - it is forcing a tyre to skid every time you turn, and that is not acceptable on the road.  What it does for a vehicle only used on private land is entirely a matter for the owner.

If you can find a way to correct the Ackerman problem with track rods up front, then great, but I don’t think I can be a done without altering the brake system - a track rod in front of the axle needs to be longer than the distance between swivel pin midpoints.  How much depends on the length of the steering arms and wheel base (both are assumed by LR as one set value, and I’d wager they use 100” as the wheel base because these parts came from the RRC).  A track rod behind the axle should be shorter than the distance between track rods.

On series axles, you can see the rod is longer and how relatively close the ends are to the brake back plate.  On coiler axles, the arms are canted well inboard, and fitting bolt-on arms like the Series vehicles is limited by the position of the brake discs and shields - if you can move the brake disc out further and omit the shield, you may be able to restore correct Ackerman.  But is it worth all that trouble just to fit disc brakes, which would no longer be standard, if a kit like Zeus or Heystee is ready to go off the shelf, with their testing and certification?

I agree, I don’t want to be messing about too much with steering geometry.

As I understand it now, by retaining the series axle case and the leaf springs, I will maintain the correct castor angle of 3 degrees for a leaf sprung vehicle. That said, a slight increase in castor may help with the front prop shaft angle and avoid the need for wide angle yokes.

The adapter (25mm?) between the two flanges will allow the swivel to bolt to the axle case and also restore the overall axle width to the correct series dimensions. To avoid machining of half shafts I can have new inner ones made to the correct length or, if they’re still available, find a long spline shaft and cut it down. Using the corners from a RRC with their 6 bolt pattern would be easier than the 7 bolt pattern.

A clash may (probably) will occur between the diff pinion and/or the leaf springs and the TCA but if this does happen then using lowering blocks or altering the angle of the diff slightly upwards may address those issues without compromising on handling. This may end up being a case of trial and error. Extended shackles may or may not be required.

Im not overly concerned about lowering the height of the vehicle as the parabolics have increased the height by around 2” from standard anyway and so I can afford to pinch some of that in favour of improved clearances.

I could retain the drag link and TCA from the series but one option may be to use a shortened TCA off a front Salisbury axle as these already seem to have the bends in them to clear the diff.

Have I understood all this correctly or overlooked something?

[Bigj66]

I noted the mention of a clash between the calliper and the shock absorber in one of the old threads. The solution seemed to be to increase the thickness of the adapter to avoid this but there’s no mention of anyone actually doing it.

Anyone got any further info on this and what an optimum thickness would be?

 I also read about people grinding off the lip on the axle flange. My thoughts are to keep this and machine the adapter to suit so it acts like a centralising spigot. Then do the same to the other side of the adapter to make a similar spigot for the swivel to locate on as per the original design.

[Wytze]

I think , i would relocate the damper. Not a wider adapter, the forces on that would be a lot higher. And yes,  keep the lip.  

[Snagger]

In all honesty, with what you have in mind there, I’d recommend you just bite the bullet and fit coiler axles outright.  The rear end is really simple on a 109 and not much harder on an 88.  The front is only a bit of a faff while you work out the shape to cut from the inboard face and contact face of the right spring saddle, and the height loss from the taller saddles really isn’t much, and can be largely mitigated by using long shackles on the front spring and rotating the saddles further around towards the front of the axle (so the diff pinion and steering axis remain the same as I have with matched chassis and shackle spec), just with the springs sloping down a bit more to give track rod clearance and drop the midpoint of the spring by the thick end of an inch.  If I remember rightly, the saddles are only about 1/4-1/2” taller than the Series original saddles (I used the standard saddles on the back, transferred rom a scrap axle).

That way, you have no geometry issues, not tricky welding (just the saddles, bump stops and rear damper brackets), you get steering lock that gives a 109 about 2/3 the turning circle of a 90, CV joints, a bit more lateral stability without the penalties of offset rims or spacers, and front discs.  Use a 300Tdi or later rear axle, and you get rear discs too.  The only snag is 3.54 diffs, and I’m not going to bore everyone again with my view off those in a Series, but with a 200 or earlier front axle, that can be swapped straight over with your current diff, and the Salisbury rear diff is a pretty simple swap with the 109’s, whichever generation of 110 Salisbury you use.

The wheel track will be wider, but with standard LR rims, the tyres will not significantly extend beyond the wing panels - 1/2” for sidewall protrusion is what I’d expect at most, so it’ll look fine and won’t need spats.

[Bigj66]

20 minutes ago, Snagger said:

In all honesty, with what you have in mind there, I’d recommend you just bite the bullet and fit coiler axles outright.  The rear end is really simple on a 109 and not much harder on an 88.  The front is only a bit of a faff while you work out the shape to cut from the inboard face and contact face of the right spring saddle, and the height loss from the taller saddles really isn’t much, and can be largely mitigated by using long shackles on the front spring and rotating the saddles further around towards the front of the axle (so the diff pinion and steering axis remain the same as I have with matched chassis and shackle spec), just with the springs sloping down a bit more to give track rod clearance and drop the midpoint of the spring by the thick end of an inch.  If I remember rightly, the saddles are only about 1/4-1/2” taller than the Series original saddles (I used the standard saddles on the back, transferred rom a scrap axle).

That way, you have no geometry issues, not tricky welding (just the saddles, bump stops and rear damper brackets), you get steering lock that gives a 109 about 2/3 the turning circle of a 90, CV joints, a bit more lateral stability without the penalties of offset rims or spacers, and front discs.  Use a 300Tdi or later rear axle, and you get rear discs too.  The only snag is 3.54 diffs, and I’m not going to bore everyone again with my view off those in a Series, but with a 200 or earlier front axle, that can be swapped straight over with your current diff, and the Salisbury rear diff is a pretty simple swap with the 109’s, whichever generation of 110 Salisbury you use.

The wheel track will be wider, but with standard LR rims, the tyres will not significantly extend beyond the wing panels - 1/2” for sidewall protrusion is what I’d expect at most, so it’ll look fine and won’t need spats.

I really don’t want to go down that road as, despite all the benefits you’ve mentioned, I personally just prefer the look of the standard track width on the series body and I also have wide wheels to start with which won’t help.

I’ve been out this morning and mocked up the series axle again that I had dismantled and also taken some measurements off the 110. I can see where the potential clash’s will be with the TCA and also the calliper and shock absorber but there’s nothing there that can’t be sorted out with some basic adjustments to heights and angles whilst keeping everything within an acceptable tolerance.

That said, this is still just a proposal that I am investigating and if it gets to the stage where I don’t think it will be safe or will adversely affect the performance of the vehicle then I will just stop and go for one of the off the shelf solutions. However, if for the sake of some additional work and effort I can save myself the best part of £2k then I’ll certainly try to do so.

 

[Snagger]

I can’t remember if Patrick Zammit Haber is a member, but he did a disc conversion on standard SIII axles using Defender callipers and discs with a specially machined bracket that forms a ring fitted to the stub axle and then forming calliper ears to achieve much the same result as the Heystee swivels.  
 

He did a great job of it, but I suspect by the time you mare the brackets, you may as well get one of the kits. I think you’d be far better off in terms of time, effort, result, safety, legality and peace of mind just to get one of them.  But drum brakes work very well if well maintained.  I only went to coiler axles because of a combination of benefits; I wouldn’t have bothered just for any one or two of them, and I’m not sure the disc kits are worth the costs compared to the mild hassle of occasional drum maintenance.

[Daan]

After all this, the heystee kit is hard to beat, as any future consumable is off the shelf. If you try to graft coilsprung axle ends onto series axles you need custom shafts, or if you fit coiler axles, you need a host of special length steering arms or weird suspension mounts, the Zeus kit has non standard discs and pads, need spacers which are the work of the devil.

Go Heystee I'd say, and I am not saying this because I am dutch!

Daan

[Bigj66]

I also like the Heystee kit and it would be my preference but if it’s possible to graft on the coiler corners then it would also give me CVs and permanent 4WD so I would save a few hundred more on the LT230 2WD kit.

As I said, if it looks like there’s not much benefit to this then I’ll opt for a kit but it’s also interesting to explore and discuss this sort of thing.

[Snagger]

If you’re fitting a later transmission, you’ll be wanting 3.54 diffs.  That is another argument in favour of the axle swap.  See if you can find some photos from someone who has done it - I understand your reservations about the aesthetics, but on standard rims and 7.50s, it really doesn’t look bad - I’m  one of those folk who doesn’t like oversize tyres, so if I could live with it, most probably could.

[missingsid]

For yor questions my spacer is actually 33 mm wide but is not enough to clear the shocks so I looked at different spring mount plates. The use of a rear spring plate had the shock hitting the axle. I ended up moving the shock pin to roughly half way between the front plate distance and the rear plate distance. You need to see what works for you.

Track rod hitting the pinion, This because the pinion angle was changes in the coiler axles as the droop on the front arms works differently to a Series suspension. They pivot from diferent directions. I chose not to bend the track rod as this makes it very weak off road when it is week enough already and you wont have room for a Sumo bar. The only option I saw was to grind a clearance in the flat bottom of the diff case.

In truth although my conversion has only cost me £700 for both front and rear which was the cost of the customer stronger halfshafts, I would have used either Haystee or Zues if I had the money.

In one of the pics above there was a comment about reusing the Series steering arm on the RRC/Defender swivle pins. This is I think a really bad idea, the Series arm/pins blot in with 4 bolts and transfer the steering forces to the hubs, the coiler steering arms are cast into the swivles so the pin bolts only hold the pins inplace and so ther is only 2 bolts. Using a Series arm on the coiler swivle pins means you resort to 2 bolts only. Perhaps in th eabove solution the swivle housing was redrilled for 4 bolts but the version I saw was only 2?

Legality of this conversion has been questioned above, unless it is unsafe it is not illegal but a commercial kit will be easier to insure?

 

If I had a Series 2 or 3 then I would have put complete coiler axles under it as they will fit without Defender arches.

 

 

[Snagger]

Sid, I think you may be referring to my post when you say about a comment recommending transferring Series swivel rods to the coiler.  I made a comment about a hypothetical use of bolt on steering arms on the swivels being fabricated to replicate the arrangement of Series units to try to illustrate the Ackerman problem if someone was considering it - it was anything but a recommendation, but you’re right that using the existing coiler swivel pin fixings they’d be extremely weak and would probably shear the first time you try turning the steering wheel.  I remember some of the Isle of Mann clique doing exactly that on the LRUK forum (the green one), and their response was that it was fine because they don’t have MoTs!😳

[Bigj66]

4 hours ago, missingsid said:

For yor questions my spacer is actually 33 mm wide but is not enough to clear the shocks so I looked at different spring mount plates. The use of a rear spring plate had the shock hitting the axle. I ended up moving the shock pin to roughly half way between the front plate distance and the rear plate distance. You need to see what works for you.

 

That figure of 33mm is interesting as it’s quite a bit more than I would have liked to consider and, a fair bit thicker than others have used without the clash with the shock absorber.

Now that you moved the shock mounting point to the mid-distance has it removed the clash?

[missingsid]

So far so good but it is no quite complete as I need new shocks. I cut the shrouds of the old ones to try to see the space. In theroy it should fit now.

 

The spacer size was to get the axes back to std width but constrained by the off the shelf halfshafts I had and this is the size I came up with. The steel used for the spacer/adaptor was EN9 plus I kept the tight fit between the component sleeves (swivel ball/spacer/axle tube) to ensure the maximum sheer strength so I am not expecting any issues between the difference in the width I chose.

I have not got a later clear picture of the issue but it is a case of ensuring the spacer, the caliper and the track rod all miss the shock. Remeber the Series axle has everything at the front except the shock whereas the coiler has everything at the rear.

Part of my problem may be the diameter of my spacer is larger than others? I chose to match the diameter of the axle flange but maybe tapering it to matck both flanges would have been better? This adds more cost to the machining but not much?

Also others may have acepted less steering lock than me? I aimed to get the 7.50 tyre just avoiding rubbing the leaf spring.

[missingsid]

More info behind my choice of 33mm for the spacer.

RRC hub face to axle flange is 225mm

Series hub face to axle flange is 258mm

Difference is 33mm

[Bigj66]

17 minutes ago, missingsid said:

More info behind my choice of 33mm for the spacer.

RRC hub face to axle flange is 225mm

Series hub face to axle flange is 258mm

Difference is 33mm

That makes sense now, cheers and the point about the steel quality and strength is well made too 👍

Are you using a vented disc and by how much is it catching on the shock? Is it just at the end of the steering lock?

If you went slightly deeper on the spacer say 40mm would that give you the clearance in the standard shock position?

[missingsid]

I am using Suffix A RRC parts so non vented non ABS.

As for any other spacer size I cannot comment as I have the perameters I wanted to achieve. The choice of steel was made by the engineering company I used to make the adapter. I figured it was safer/easier (Idon't have a lathe) and easier to insure? The last will be interesting as it is not on the road yet.

[missingsid]

This is weird with lockdown as I am not used to suck quick responces!!

 

A wider track by extending the spacer will increase the ability to turn the steering more but put more bolt risk in to the calculation. The sheer forces will be still managed by the spacer sleeves but the increased leng will increase the leverage to stretch the bolts.

[Bigj66]

1 hour ago, missingsid said:

This is weird with lockdown as I am not used to suck quick responces!!

 

A wider track by extending the spacer will increase the ability to turn the steering more but put more bolt risk in to the calculation. The sheer forces will be still managed by the spacer sleeves but the increased leng will increase the leverage to stretch the bolts.

Cheers. It wasn’t the steering lock I was after it was just about making sure the calliper was clear of the shock.

If I go this route I will also have someone make the spacer up for me and do the calcs.

I’m on with this project on a daily basis so always checking the forum for updates. Quick responses are always appreciated 👍

[Snagger]

You won’t have any of those damper fouling issues with a coiler axle.  You can use the 88” rear spring plates swapped over because you don’t have the swivel flange diameter to contend with.

MissingSid seems to have got a lot of the problems sorted with those collars, shaved diff and fabricated damper mounts, but you still need special shafts, which will be a real pain anytime you break one.  Hopefully a rare event, but it’ll cost a lot more time and money to repair should it happen.

Obviously your choice, and I can see why you want to retain the standard look, but I think you’re barking up the wrong tree, adding complexity and cost for few advantages when a simpler mod gives more advantages at less cost.

[Bigj66]

1 hour ago, Snagger said:

You won’t have any of those damper fouling issues with a coiler axle.  You can use the 88” rear spring plates swapped over because you don’t have the swivel flange diameter to contend with.

MissingSid seems to have got a lot of the problems sorted with those collars, shaved diff and fabricated damper mounts, but you still need special shafts, which will be a real pain anytime you break one.  Hopefully a rare event, but it’ll cost a lot more time and money to repair should it happen.

Obviously your choice, and I can see why you want to retain the standard look, but I think you’re barking up the wrong tree, adding complexity and cost for few advantages when a simpler mod gives more advantages at less cost.

But if I don’t like the look of the finished result then no matter how beneficial the mechanical side may be, I still won’t be happy with it.

[Gazzar]

What, exactly, is the problem? The cost of doing to disks?

[Bigj66]

1 hour ago, Gazzar said:

What, exactly, is the problem? The cost of doing to disks?

There isn’t a problem, I’m just looking at options for upgrading my brakes 🤷‍♂️