So, tonight I encountered another nuisance issue, with the reconditioned disco axle not matching up to the 90 chassis its going on. The spring mounts are too far forward, throwing off the angle.

I'm at a stage where, having welded on a new diff cover/oil pan and had the axle shot blasted, zinc sprayed and painted it, I'm loathed to start cutting and welding. But moving the mounts round seems like the only thing to do??? I did consider making an asymmetric wedged packer thing, to make some contrived marriage here. But another factor is the damper stud thread, which is barely long enough to poke through the thickness of the mount material and fasten up with the bushes.[GALLERY=][/GALLERY]

Disco and 90 axle casings should be the same.

Rougharse Racing said:

Disco and 90 axle casings should be the same.

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That's what I was told. Discovery 1 and early defenders/90. But I have measured the radius arms to the middle of the spring mounts, and the disco ones are longer by 1/2".

Rougharse Racing said:

Disco and 90 axle casings should be the same.

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This is a rebuild on a new Marsland galvanized chassis, which I was sure is built to the highest standards of accuracy. I ordered a 200tdi version, but my local 4x4 chap saw it and said "why did you order a Td5 one?". Still, I doubt they would change the geometry?

It’ll be fine with some weight on it. Make sure the radius arms are fully seated. There shouldn’t be any difference in length, they’re all the same.

Marsland chassis have the later crossmember which is probably what your 4x4 chap is wrongly referring to.

Retroanaconda said:

It’ll be fine with some weight on it. Make sure the radius arms are fully seated. There shouldn’t be any difference in length, they’re all the same.

Marsland chassis have the later crossmember which is probably what your 4x4 chap is wrongly referring to.

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Ok, I don't mean to be awkward, and to be fair I'm the novice and you're all experienced at this. But there is a clear difference in distance of at least half an inch from the radius arm mount on the chassis to the center of the spring pad mounts on the axle. Those mounts (can you see the pic I posted?) are in a different position, facing too far forward, and they are too far out of alignment to build the front end with the springs in place

It’s possible the mounts on the axle have been put on in the wrong place, but unlikely. Have a look at these two threads - same issue being flagged.

https://forums.lr4x4.com/topic/47257-front-spring-alignment-on-a-90/

https://forums.lr4x4.com/topic/85759-spring-alignment-on-new-build/

Retroanaconda said:

It’s possible the mounts on the axle have been put on in the wrong place, but unlikely. Have a look at these two threads - same issue being flagged.

https://forums.lr4x4.com/topic/47257-front-spring-alignment-on-a-90/

https://forums.lr4x4.com/topic/85759-spring-alignment-on-new-build/

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On the first link, he has posted two pics. The 2nd pic shows the radius bone connected to the chassis bone. As you said, as the weight builds from above, that will come down and the angle will look right.

The 2nd pic shows the problem I've described. I have new polybushes, and everything is in tight with no movement in any of the joints, but the direction in which the mounts face is disconcerting and wrong! Which leads me to believe you're right in that, against the odds, the geometry is not correct. I can't see an option other than repositioning those mounts! I'm curious, whether I might encounter any more unpleasant surprises forcing a backtrack with more work?

Retroanaconda said:

It’s possible the mounts on the axle have been put on in the wrong place, but unlikely. Have a look at these two threads - same issue being flagged.

https://forums.lr4x4.com/topic/47257-front-spring-alignment-on-a-90/

https://forums.lr4x4.com/topic/85759-spring-alignment-on-new-build/

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As you say, the advice on those threads is to get some weight on there. A variation in geometry should be flagged up, but wouldn't necessarily be recorded by land rover in their workshop manuals.

I haven't secured the bolts that fix the radius arms to the axle, so will try and bring the axle round a bit with ratchet straps

Jack the axle up to the height it would be normally, it will pivot up at the rear of the jockey stick arms and then the mounts should flatten off and line up.

I took both my front hockey sticks off and dampers and the whole lot shunts out of place and looks wrong, it will likely pull up straight.

The photo of your axle doesn’t look like it’s near where it would with wheels and springs and weight on it.

I don’t know if I have explained that right but does that make any sense?

flat said:

Jack the axle up to the height it would be normally, it will pivot up at the rear of the jockey stick arms and then the mounts should flatten off and line up.

I took both my front hockey sticks off and dampers and the whole lot shunts out of place and looks wrong, it will likely pull up straight.

my he photo of your axle doesn’t look like it’s near where it would air with wheels and spring and weight on it.

I don’t know if I have explained that right but does that make any sense?

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None whatsoever flat, except that by 'hockey sticks' I presume you mean 'the radius arms'?

Having pulled my 1988 land rover 90 to bits, there was quite a bit of slop with those components, as the bushes were totally worn out. But even with everything firmed up with the new polybushes packing everything out, and without to the bolts tightened, there is no where near enough movement to get the upper and lower spring seats to face each other. I can show more photos but it looks just like in the links posted by Retroanaconda above. It just isn't right. Everyone is saying get some weight on it, but it won't go together satisfactorily on the first place, and that's not right. As I say, the original radius arms are slightly shorter, and I'm convinced the mounts are attached in a slightly further forward position. This makes sense to me, as I am also convinced the disco chassis is slightly different, but I don't want to contradict experienced guys on here that tell me they were all made the same.

I just think there may be an anomaly in the manufacturing or design at that time, that was never really flagged up? I dare say its probably rare unique to my build, which is also a conversion, using a new chassis for a defender and the axle off an early (1994 300tdi disco...

If you guys could physically see how much of a misalignment this is, you might concur that it is different, and not at all what we want.

It occurs to me that, unlike the rear axle, where the trailing arms can pivot where they connect to the axle, and therefore there can be straighter up and down movement in service, the front axle is suspended more or less captive at the front end of the radius arms, so the front axle is definitively moving in an arc (hence the term 'radius').

So, logically there will be a range of positions and angles through which the spring mount pads will be travelling, but I suspect this is minimal, not as much as 20mm which is what we are looking at here.

Anyway, I appreciate all your help and thoughts on the matter, I'll probably make a decision on what to do when I've heard back from BritRest Mike in Canada.

Best wishes to all you land rover brethren

Do you have the original radius? Do they fit the axle? Do a trial fit with the old ones and see what you have.

J

Are the radius arms (hockey sticks) torqued up at the chassis end?

No engine in I presume?

what I mean by the axle is it looks like it’s tipping forward to much - I.e not in the orientation it would be with the engine in, wheels, weight on it etc

when weight is on it the radius arm is parallel to the chassis

Like this, which you can sort of see - if that make sense

is what I meant by ‘jack the axle up’ is so that you can get it sitting at the level it would normally and then see what lines up etc. You will have to slacken off the radius arm bolts tbh to do this, as they should be final torqued with the vehicle weight on (iirc)

rotate the photo, I don’t know what it’s turned on it’s side

Hammer'n'tongs said:

This is a rebuild on a new Marsland galvanized chassis, which I was sure is built to the highest standards of accuracy. I ordered a 200tdi version, but my local 4x4 chap saw it and said "why did you order a Td5 one?". Still, I doubt they would change the geometry?

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There is a difference between earlier and later radius arms, the later being thicker at the axle end. Although I've had both types laid next to each other I didn't compare the lengths and probably wouldn't have noticed half an inch, though like you I doubt that the geometry would have been changed by moving the chassis brackets.

You mention not having the bolts to the axle 'secured' but I see the back ones in - are the front ones there? That could definitely affect things.

It's a Granny/eggs question, but you have got the bushes all fitted correctly at the chassis end of the arms and all squished down properly?

I'll get a picture of the one I have in build and you can compare how distorted mine looks (although it's not exactly standard). Pics tomorrow.

What make is the new chassis?

You wouldn’t be the first person to get one with a bracket in the wrong place.

Retroanaconda said:

What make is the new chassis?

You wouldn’t be the first person to get one with a bracket in the wrong place.

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He said it’s a Marsland, so should be a GKN. I doubt they would get it wrong.

I still think that when the axle is in the correct position relative to the chassis it will line up, in his photos it isn’t.

It will be stiff to move because of the new poly bushes

flat said:

I still think that when the axle is in the correct position relative to the chassis it will line up, in his photos it isn’t.

It will be stiff to move because of the new poly bushes

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I agree that it should be fine. I also agree about what you said earlier, all the bushes should be “loose” until the weight is on, then final torque applied. I originally thought that maybe it had castor correction bushes fitted, but done wrong, and possibly caused the issue.

mick 1986 said:

I agree that it should be fine. I also agree about what you said earlier, all the bushes should be “loose” until the weight is on, then final torque applied. I originally thought that maybe it had castor correction bushes fitted, but done wrong, and possibly caused the issue.

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yep, and I think it would be a mistake to chop off and re-weld any mounts until it’s been checked again by jacking up or with weight on