Thread: lifted springs for series landrover?

Originally Posted by Series3 GT

Well I might look at fitting some, the springs have sagged down a fair bit so an inch of lift will probably be only a bit over standard. Has anyone got some or a design they've used.

They are just flat steel plates, however the inner plates are threaded. Last I needed to replace some, they cost $7 each from a LR place (Maybe FWD in Brisbane).

Aha! This ties in nicely with what I've been doing.
I've got a 2a SWB with the front springs sagging about 30mm from spec.
So rather than trying to go for a reset (as the spring still has some curve) I thought I'd make some shackles and do it cheap.
Since the sag was 30mm over half the length of the spring, a 60mm extention should do the do. Made the shackles easily out of 10mm plate and some 21.3x 3.2mm pipe. Pipe needs running though with a 9/16" bit as the seam makes it a bit tight.

Fitting the shackles was a bit more involved than I thought as the spring wouldn't droop as far as it needed whilst still attached to the axle even with the shock disconnected, but a long bit of timber and body weight allowed me to fit the shackle.

As soon as it was fitted you could see the pinion angle was way out. I put the jack under the spring so it could take weight, but even then the spring seemed high and the pinion was still out.
I didn't put the wheels back on and allow for fully settling, as I decided to do some calcs and work out what the pinion change would be with a 30mm lift.
What I'd forgotten to take into account is that as the spring sags the arc of the spring changes and the distance between the shackles lengthens, this means that the castor doesn't change too much as the centre of the spring stays relatively flat to the original position. This changes when you pivot around the front shackle pin when using extended shackles.
The spring pivots around the front hanger, so the distance from this to the centre of the axle was used to work out the degree of change when lifting 30mm.
Distance from front hanger to axle = 450mm
Lift = 30mm
To make the maths easier I ignored the axle path and assumed it straight, and made the isoceles triangle into 2 right angled triangles with a side of 15mm.

So using Pythagorus sin(deg)=Oppo/Hypot; deg = sin-1(15/450)
deg=1.9deg
total degree change for 30mm lift =1.9x2 = 3.8deg

This is a major change when it comes to castor and operation of U-joints, so you'll definitely need castor plates to convert back to spec.
Length of axle plate where it contacts the spring = 100mm
Need to roll the axle 3.8deg.
this means the back of the axle need to be lifted: sin(3.8)x100 = 6.6mm.

Measuring my U bolts I don't have 7mm of extra thread to accommodate the necessary wedge.

So my cheap fix is starting to look a bit more involved ( and expensive).
A set of wedges retails for between $50 and $80, and then U-bolts are ~$50 assuming you can get the right shape and length.
So you're looking at $150 to bodge a fix (assuming you build your own shackles) or $350 for a new set of parabolics.

It might be as well to go for the parrotbollox, but then do you need longer shocks, extended brake lines...