Wonky springs - please advise!

[Tsavo]

Hello fellow 70 series owners!

A few weeks back I had my mechanic replace my old and embarrassingly weak coil springs with new Iron Man 50mm lift 'performance' springs all round. Yesterday I fitted new longer, rear shocks to match the new coils. While I was under the vehicle I noticed (see photos - damn hard to get good shots of the springs!) that the springs are sat slightly bowed/arched. The rear pair arch backwards towards the rear and the front pair arch outwards towards the side of the vehicle.

I was of the understanding that a 50mm/2" lift does not require any suspension geometry correction but in my (inexperienced) mind these bowed springs may suggest otherwise. The arch is not severe and the vehicle still handles ok but I can't imagine driving on Kenya's bumpy corrugated roads with bent springs will be a good idea in the long run.

I might guess that the trailing arms are now 'short', the leading arms need castor correction and the front panhard rod/lateral control arm is also 'short'. Can anyone advise if I'm on the right track here? Can I resolve this with offset bushes?

Kenyan small-town mechanics rarely have any experience with modified 4x4's - if any of you 70 series wizards out there could help I'd be chuffed!

Thanks - Ewan

PS it's a LJ79 (3L engine), 235/85 R16 tyres, pretty much stock other than suspension and roof mods.

PPS I bought the vehicle with those horrible Dunlop tyres - don't judge!

 

[Tommy345]

Which Dealer did you purchase the springs from??

 

[Tsavo]

I bought them from SaiRaj in Nairobi - the official supplier of IronMan 4x4 parts in Kenya. The product codes are stamped on the side of the coils and match the IM catalogue.

The first set of rear coils they sent looked scratched/worn as if they had been a display pair. I called the supplier and they were enormously apologetic - immediately sent me a replacement pair with a promise of a big discount for any new order...

 

[Tommy345]

Have you got in touch with them since fitting this set to ask there advise?

 

[Chris Boorer]

Are these pics with the original shocks still attached if so that will be the reason

 

[Tsavo]

Front shocks are OEM and but rear are Robs Magic which are much longer than standard. Old rear shocks were sitting near to fully extended but front have plenty of travel both ways.

I haven't got in touch with the supplier, I may well do but hoping for some experienced insight into this from 1 or 2 of the wizards from the LCC.

Thanks!

 

[MarkW]

Which springs did you use? Iron-man springs come in a range of weight load option, normal, upto 300kg constant load and a 300kg+ constant load.

As a guess I think the springs are too soft for the weight causing them to bow like that

 

[Roger Fairclough]

You will automatically get a slight kink or bend in the new coils because they are sitting on mounts that are designed to suit standard springs. The new springs increase the angle between the mounting for the trailing/leading arm, and the upper and lower spring mount. Imagine that this increase is 90 degrees and now look at the spring and see that it is only sitting on a corner of its mount. This is an extreme example but it illustrates why the spring is kinked and also why a small lift can upset the castor angle.

Roger

 

[Tsavo]

Ok great - big thanks Roger. Good to have it confirmed as a castor angle issue. I can easily get a set of Iron Man or Dobinsons castor correction bushes within the next few days. Looks like these - https://www.superpro.com.au/show-product/superpro-bushing-kit/orphan-SPF1721K - or the IM equivalent should do the trick.

Would I be right to assume fitting these to the leading arms should correct the bend in both the front and rear springs?

Thanks again, Ewan.

 

[Roger Fairclough]

Sorry, I used the castor angle as purely an indication of the effect that even a relatively small lift can have of other parts of the suspension. Saying that your 50mm lift will change the castor angle and may put it outside factory spec. If you notice a degree of vagueness in the steering then correction bushes may well be on the cards but to be certain have the suspension settings checked . Check on Google for companies in your area.

Back to your springs and yes my original comments still stand. As you increase the angle between leading and trailing arms the spring mounts are no longer parallel at rest and the springs are forced into a kink. This is the same front or back.

Roger

 

[Tsavo]

Thanks Roger. Your explanation has definitely helped me to understand the issue now. To complicate things slightly, however, my steering has some wander and very little returnability even before the suspension lift so I'll have to look at the steering gear etc. before making any correction to the caster angle...

 

[Roger Fairclough]

There are a number of factors you need to check.
Firstly, the mounting bolts that connect the leading/trailing arms to the chassis (130 ft-lb) and the lateral control rods (Panhard rod) ( 106 ft-lb at the bush end and 92 ft-lb to nearest cotter pin hole ) must only be tightened once the motor is on it's wheels and you have settled it down by bouncing it up and down a few times. All bushes must be checked and replaced if damaged. The split one on the axle end of the lateral control rod can be sloppy even when fully tightened: if so , replace.

Another possibility will be the steering knuckles and problems here will depend on mileage between overhauls, total mileage and conditions of roads etc. Condition of wheel and steering knuckle bearings plus their pre-load is vital. Also check the ball joints on the relay and tie rod.

Roger