Thread: Hilux inverted leaf springs

I will make some phone calls when I get a chance next week

Originally Posted by Flyblown

@hunt08

Mate, this is not a difficult problem to solve.

Get in touch with one of the suspension specialists in Hamilton. I recommend Automotive Solutions Hamilton. They carry Lovells springs which is a superior brand used throughout Australia for commercial vehicles, not a flash Harry 4WD product but a proper working vehicle product. Tell them what you need, they will tailor the right package, you drive up from Wanganui early on the day, drive home later that afternoon in what will feel like a completely different vehicle.
@MSL is someone to ask, pretty sure he used these guys in Hamilton as well. Maybe someone else. Either way he was very happy with his Hilux suspension upgrade, also for loads & work use.

Like I say, not hard, it’s gonna cost you but it will it will transform your Hilux and last forever.

Yep, good advice. I found exactly what you did, about 3 shops/dealers including Ford's local walked away and couldn't sort it after the uprated rear leafs were installed (they were done leaving the factory shocks at the back and front untouched due to smashing towball shanks on driveways and not being able to connect trailers up as the jockey wheel would not wind down enough to unweight the trailer coupling). This is why I'm saying you need to do the front at the same time, what happened to mine is the rear lift through fitting the 7-leaf pack took the front end past the limits of the alignment devices and effectively turned the vehicle into a widowmaker - the front end would just depart control with zero warning and slide to one side or the other. On gravel, ended up needing to operate it like a rally car - in 4wd and the boot hard up the boitch to pull the front end straight. Total pain in the arse...

Ford left the chat at this point, so I had to find someone to fix it which is when I found out I couldn't as basically there wasn't anyone with the knowledge on the PX ranger at that stage. Imported a set of foam cell shocks and struts and front springs - fitted them which meant it went a lot better but the front end on heavy springs without a bar or winch meant there wasn't enough weight over the front axle so it drove like a forklift. Cornered amazing though haha.

Took the aftermarket coils out, and put the standard back in - luckily I had dimensioned everything prior to doing the mods so a bit of a run with the calculator and a few well aimed guesstimates was how I ended up with a 10mm spacer on the front strut to slightly increase the front end preload. Next problem is the spacers were not available in NZ and on 3 month backorder in Aus, so I had to bloody make them! Another pain in the arse. All done, it was a massive improvement in ride quality, compliance when hitting bumps etc and also road manners - the interesting one is the traction control was a lot more gentle and smoother when engaging rather than the crash when it was on factory gear.

As @Flyblown said, I had automotive solutions fit some EFS uprated leaf packs and KYB scortched earth shocks to the rear of my 2014 hilux. My Old man emu uprated leaf packs had done the sad face bend.


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Huh, didn't know that airbags require a cert. Also didn't know that a cut down leaf required a cert as well...
I'm amazed if they are getting that strict that you can replace the leaf pack with an aftermarket and not need a cert!
--https://vehicleinspection.nzta.govt.nz/virms/in-service-wof-and-cof/general/steering-and-suspension/steering-and-suspension-systems
the springs or shock absorbers are direct replacements, and
replacement springs are contained within unmodified OE seats throughout full suspension travel (Note 8), and
replacement springs are self-retaining in their seats at full extension, without the use of non-standard devices such as wire-ties, straps, or external spring locators, and
replacement springs have not been heated or cut, and
springs and spring seats are not height adjustable by any means (unless OE) (Note 9), and
replacement shock absorbers, including air-adjustable units, fit unmodified OE mountings (Note 8), and
suspension maintains sufficient travel for safe operation (Note 10), and
suspension components maintain sufficient clearance from unmodified bump stops when fully laden (Note 11), and
Suspension retains at least 40mm of rebound (droop) wheel travel (Note 12), and
a minimum of 100mm ground clearance (unladen and without driver) exists below any part of the vehicle structure, or any steering, braking or suspension component (Note 13) and
the normal relationship between front and rear suspension height is not unduly affected, and
clearance is maintained between all components, when tested from lock to lock at full droop

But yeah, those leaf packs look about right from where my experience of these things go - they aren't that dear as indicated. But add to that price doing the rear shocks as the factory gas struts just won't handle those springs at all, the biggest single change you can make is replacing the shocks and even just doing the shocks will make a hell of a difference to how the factory springs behave.
Yup, you'd chuck some decent shocks at it too
I think that the main issue with the factory shocks is that they are designed and calibrated for the vehicle unloaded and they do that well, expect that we in NZ suddenly hang towbars on the back and expect the vehicle to suddenly do the work it's designed to do empty but at full axle loads. Something has to give, and in this case the gas-oil factory shocks suddenly find their operating cycles go up a huge amount and the result is heat. Heat is the enemy of shock oil, the viscosity lowers as the oil heats up and it passes through the shocks valving much more quickly and reduces the damping effect. This in turn means that the springs start getting smacked in to next week with no damping, and this is how the springs end up going past their elastic limit.
Yep

The next problem is the suspension at both ends must work together to keep everything pointing the same way - if you upgrade the back end the front will feel like absolute garbage. As a minimum get the matching set of front struts to the back, and retain the factory springs. You may require a spacer on the spring to increase the preload slightly - my understanding of the rules is that provided you don't increase the lift past 50mm and don't have anything adjustable without disassembly you are able to do this without cert. For reference, most of the ute double wishbone front ends run a 2-1 design ratio which roughly means a 10mm spacer increasing the preload on the factory spring gives about a 20mm lift at the wheel. You won't notice the effect of the spacer on travel or articulation in normal conditions. Again, that's going to require cert - "Note 8- Strut or spring spacers always require certification."

Originally Posted by hunt08

I will make some phone calls when I get a chance next week

It’ll be all good, just explain what you are using the ute for, ute tray loads and trailer loads, types of roads. They’ll have a pretty standard product for you on the shelf, pretty sure of that. Remove the old, bolt on the new, not a big job, done it heaps of times myself at home with Hiluxs going back to the early 90s. Even did it once on a hill in Malawi. Carried spare spring packs on the front of the vehicle… very handy to stand on.



(yes, I know, posted probably a dozen times already)

Similar to the Expedition series Landies operating in Mozambique when I was there. Fully loaded with camping and hunting gear for three weeks. Plus punters on board. Pathetic front diff spider gear shaft, so better carry a spare diff head. Half shafts snap like carrots, so lets carry three spares. Wagon is now looking overloaded, so better carry a couple of spare leaf packs...and so on and so on.

Originally Posted by Tommy

Huh, didn't know that airbags require a cert. Also didn't know that a cut down leaf required a cert as well...
I'm amazed if they are getting that strict that you can replace the leaf pack with an aftermarket and not need a cert!
--https://vehicleinspection.nzta.govt.nz/virms/in-service-wof-and-cof/general/steering-and-suspension/steering-and-suspension-systems
the springs or shock absorbers are direct replacements, and
replacement springs are contained within unmodified OE seats throughout full suspension travel (Note 8), and
replacement springs are self-retaining in their seats at full extension, without the use of non-standard devices such as wire-ties, straps, or external spring locators, and
replacement springs have not been heated or cut, and
springs and spring seats are not height adjustable by any means (unless OE) (Note 9), and
replacement shock absorbers, including air-adjustable units, fit unmodified OE mountings (Note 8), and
suspension maintains sufficient travel for safe operation (Note 10), and
suspension components maintain sufficient clearance from unmodified bump stops when fully laden (Note 11), and
Suspension retains at least 40mm of rebound (droop) wheel travel (Note 12), and
a minimum of 100mm ground clearance (unladen and without driver) exists below any part of the vehicle structure, or any steering, braking or suspension component (Note 13) and
the normal relationship between front and rear suspension height is not unduly affected, and
clearance is maintained between all components, when tested from lock to lock at full droop

But yeah, those leaf packs look about right from where my experience of these things go - they aren't that dear as indicated. But add to that price doing the rear shocks as the factory gas struts just won't handle those springs at all, the biggest single change you can make is replacing the shocks and even just doing the shocks will make a hell of a difference to how the factory springs behave.
Yup, you'd chuck some decent shocks at it too
I think that the main issue with the factory shocks is that they are designed and calibrated for the vehicle unloaded and they do that well, expect that we in NZ suddenly hang towbars on the back and expect the vehicle to suddenly do the work it's designed to do empty but at full axle loads. Something has to give, and in this case the gas-oil factory shocks suddenly find their operating cycles go up a huge amount and the result is heat. Heat is the enemy of shock oil, the viscosity lowers as the oil heats up and it passes through the shocks valving much more quickly and reduces the damping effect. This in turn means that the springs start getting smacked in to next week with no damping, and this is how the springs end up going past their elastic limit.
Yep

The next problem is the suspension at both ends must work together to keep everything pointing the same way - if you upgrade the back end the front will feel like absolute garbage. As a minimum get the matching set of front struts to the back, and retain the factory springs. You may require a spacer on the spring to increase the preload slightly - my understanding of the rules is that provided you don't increase the lift past 50mm and don't have anything adjustable without disassembly you are able to do this without cert. For reference, most of the ute double wishbone front ends run a 2-1 design ratio which roughly means a 10mm spacer increasing the preload on the factory spring gives about a 20mm lift at the wheel. You won't notice the effect of the spacer on travel or articulation in normal conditions. Again, that's going to require cert - "Note 8- Strut or spring spacers always require certification."

Ahhh - that's how those particular ones I got are able to do it then. The lower spring cup is a separate part to the shock body on the foam cell struts I got which is where the spacer goes - between the lower cup and the strut body and cup stop ring. The spring remains fully contained within the designed elements of the strut and factory upper mounting. It's a designed system and non-adjustable once the spring is in place and serves to only control the preload on the coil spring. Probably a better term is a preload adjustment element rather than spacer? It's not a spring spacer or a strut spacer according to that definition. Good to know... Thanks.

On the other hand - how in the hell do ute makers claim that their products meet WOF specs at full load when with half of them the vehicle is sitting ON the bump stops at 500Kg below max rear axle weight? I've often asked this and get the 'mumble mumble mumble' reply.