Thread: Hilux inverted leaf springs

Hi my Hilux leaf springs are inverted & it's affecting the towing off big trailers to be fair it towing like shit now use to tow really well & are towing the same trailer with the same load.I have got a 3 year old Hilux it's done 90 thousand km the springs are factory the Ute is a double cab well side with a canopy on I'm thinking I need to upgrade the springs but don't know what to go to I don't want to give it a 2 inch lift I'm happy with factory height whatever I put in needs to be able to ride good when empty as I don't carry big weights in the canopy very often but do a lot off towing weight off trailer & load would be round 2-2.5 ton. So my question is what would you put in the back so it rides good empty but can handle the weight off a big trailer thanks

Factory rear springs but add another factory main leaf with the eyes cut off, taper the cut to avoid concentrating load stress at the cut

The D bolts are long enough, just make another centre bolt and trim to length

Adds a large amount of load capability and rear stability

Do a bit of math on it, work out what your standard weight on the rear spring pack is and then divide by about 75 (Kg, which is about what each leaf will carry). I went from the standard 3-leaf plus overload plate to a 7-leaf plus overload on the ranger. Fixed the junk springs it shipped with and the bs ride they gave, now much more acceptable although I would not like to be in it fully empty.

I have a wellside, liner tub, 75Kg of canopy and 65Kg of ute drawer in it permanently plus probably 45Kg of tools?

Plan to upgrade the shocks at the rear and you will need to adjust the front to correct the ride height and sort the alignment most likely. With more leaves in the rear spring pack you will gain lift which will also drop the nose and this is not good for alignment. I set the new foam cell front struts up with the factory coils but with a 10mm spacer to increase the preload which gave me 20mm lift at the front which pulled everything back into correct alignment. So far no issues with driveline angles, 136,000Km and the front lower ball joints need replacing it's the only wear item so far.

I'll add to that, for 2500Kg trailer that should be 250Kg of downforce on the towball which is all back end no load sharing to the front. With a canopy of say 65Kg for a plastic type your towing load increases over empty by 315Kg - I would think that a leaf pack designed for medium load carry or 50% of max rear axle load might work? Probably a 5 or 6 leaf pack depending on who supplies it. Or maybe the modified leaf mentioned above plus one standard mid pack leaf on each side, will need new u bolts and center bolt though you won't squeeze two more leafs in with the factory bolts.

Go to a decent spring / suspension shop.and ask for some advice. I did this with my navara and it tows way better. But these have coil spring rear end . I'm sure there will.be a heavy duty spring set that can be offered. It's no different than any industry .the best advice is professional advice. It's a good starting point you can always decide upon what to do on your budget. I wonder why they flip the leafs..we use to do this in our cars back in the day to lower them.lol

Air bags. I adjust my load regularly

I've used airbags a couple of times on work vehicles, they can be a pain in the arse if for some reason one side ends up at a different pressure to the other. They do seem to improve the ride but to my thinking it's just another thing to have to do. If you are towing all the time but then for some reason not towing and deflate the bags for ride comfort and get a surprise tow job come up you have to pump up the bags. That means carting a damn compressor or pump with ya, just more crap!

My thoughts are just sort the suspension out right first time, get it set up for the loads you normally work with and the vehicle will go better for it. The chassis for one will be happier without smashing the bump stops all the time, and for some vehicles even things like airbags can stress the chassis where it's not reinforced for it.

Just keep in mind that adding cut down springs to spring packs, and airbags, all require cert.

A replacement spring pack perhaps? They're not expensive

https://motortech4x4.co.nz/product/o...hilux-2015-on/

In 1996 we were running a fleet of Jeep Cherokees XJ's in Cambodia with the UN. Some donor coughed up for 50 new Hiluxes and when they all turned up the (Cambodian) Service manager had a fit, as all of the front suspension had inverted leaf suspension. All he was used to was the XJ's conventional rear suspension packs, so he thought they were all rooted from new, and someone had done the dirty on him. Took a few photos of what a new Hilux looked like in Japan and America for him to calm down

By the way, we had an AWFUL lot of fun thrashing the snot out of those XJ's out on an old dirt airstrip in Campong Chhnang before sending them back to the knackers yard. Reverse J turns, evasive manouevers etc etc. Oddly enough none even tried to overturn. Bloody good wagons those.

Originally Posted by Tommy

Just keep in mind that adding cut down springs to spring packs, and airbags, all require cert.

A replacement spring pack perhaps? They're not expensive

https://motortech4x4.co.nz/product/o...hilux-2015-on/

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!

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.

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.

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.

Originally Posted by Quackers

Go to a decent spring / suspension shop.and ask for some advice. I did this with my navara and it tows way better. But these have coil spring rear end . I'm sure there will.be a heavy duty spring set that can be offered. It's no different than any industry .the best advice is professional advice. It's a good starting point you can always decide upon what to do on your budget. I wonder why they flip the leafs..we use to do this in our cars back in the day to lower them.lol

I have been to 3 tyre shops & Toyota (witch I have tried twice & they haven't bothered to come back to me with anything) in town and the only 1 has come back to me & they are saying just to replace the rear springs and putting lot bigger shocks in and priced around $2000 we don't have any specialised suspension shops in the town that i live in

I'm not putting airbags in I know off other Utes with them & they all hate them & wished they had saved there $1000 & are getting sick off taken them out for wof because they haven't cert them lol

Who makes the best springs is it is it best to go out off town to the likes off arb I have never change the springs or shocks in a vehicle before so that's why I'm asking on here as with only 1 shop coming back to me I'm not getting much advice sure i could chasse them up but I'm more like if they want my $ they will do what they say they will & if they don't I'll go elsewhere lol

@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.

Ring auto lighn mt wellington In auckland and talk to Ian.

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.

Thanks for that I know it's not hard thing to solve but it's finding the right people to do the job that know what the talking about is the hard thing when I don't know enough about it to know when sales people are talking shit to make a sale lol