Kzh138 2inches lift heavy duty suspension upgrade?

Hi guys

Just got my Hiace sc kzh138v 96 recently and I’m learning the Van.

I’m Planning to rip all interior out and fit a fixed bed at rear end with 2x leisure battery,inverter,water tanks,storage under the bed.

My questions , I would like to upgrade my stock suspension to a lifted 2inches heavy duty one ,i did checked on toyodiy.com but it only show stock parts number!?

Thanks in advance

Kami

Hello

I’m a bit puzzled as when I put the KZH138V into the EPC it only comes up with a single variant, a model KZH138V-EFPDT and this has torsion bar front suspension and coil springs at the rear so something is odd here, if your van has leaf springs.

Is that variant correct for your van based on the build plate?

Is the build plate (sort of Japan’s VIN plate for JDM) correct based on the features that the van has?

The build plate is under the passenger seat. You can decode the build plate via the manuals and resources on Hiacesoutheast so I’d start there. This is important to get right. There have been posts from owners who thought they had a ‘K’ series engine but it was actually fitted with a ‘L’. It’s possible that your build plate has been swapped, but let’s hope not. The build plate details may also be included in the paper documentation and importantly the frame number is on the build plate and under a flap that’s revealed when the driver’s door is opened so useful as a sainity check. The engine type and capacity (but not its serial number) is also on the plate along with other important gearbox etc codes.

Right to leaf springs…

There are several types, but as I replied to your other post getting comprehensive details is difficult.

Via the EPC (I don’t find toyodiy that useful) you have to select the model first, but you can then see where else it’s used. Often this is not a lot with the Hiace.

It’s much easier via the Amayama site as you can select a part area then narrow this down by model.

Anyway, there are definitely different rear leaf springs. The type available (but not in stock I think) on Autodoc is a four leaf and it says not for motorhome. The motor home (eg LH119 like mine) has a five leaf construction (look it up on the EPC).

If you look in this post (on towbars), you can sort of see leaf springs of various types, at least in terms of the position of the dampers so there might be other differences:
https://hiace-super-custom.forumotion.com/t3686-tow-bar-for-1994-super-custom#24871

If you look on the ‘CarsAndBids’ site for Hiaces etc you can see some sold examples and there are lots of detailed photos of these and there are underneath snaps and these show various leaf spring types.

I think (but not absolutely sure), if you want the leaf spring with the heaviest capacity then get the variant off the LH119, but you can’t get them from Toyota UK anymore. You can still get them from Amayama.

I’m getting a company called Owen Springs (Rotherham) to make some new ones for me. These will be bespoke but to their pattern book and they are waiting for me to drop off one of my old ones so they can check and compare before they make my new ones. I doubt they will make a variant they don’t have in their pattern catalogue, but you can ask. Btw, I contacted quite a few companies in the UK and they were by far the most knowledgeable and helpful.

As said previously if you want a lifted example then fit longer rear shackles as Fixer Merlin has done; see his YT. You will have to get right into the details on this but any 4x4 / specialist LandRover or Toyota off road specialist garage can help with this, but it’ll take a bit of work.

So, more work for you to check!

HTH!

Hi LH119V

Thanks for Infos.

I

Just check my VIN number, see the picture above my Van is Kzh138-0001726 with A340F G295.
Initially, I thought all Hiace is leaf's springs set up so I didn't even go under the van to check it! but I was totally wrong !?

Yes, I checked it my van is coil springs at the rear, So I need some beefed-up lifted coils for the rear end to carry extra weight and also new shock's all round.

Lot's to learn here.

Thanks

Kami

Kami
I have the SC 132 Semi high roof same info on the vin plate , GVW is not given and suspect if we tow a trailer without the Gross train weight shown and axle weights shown it is illegal , I overcame this problem by having a it replaced .

Kami,
I posted these dimensions of stock shock absorbers

link: stock shock absorber dimensions

Usual 2" lift consists of following:
1. rear coils from another vehicle (in Australia Pedders supply coils from an earlier Ford Falcon)
OR
coil spacers....I got some machined from aluminium billet

2. replace rear shock absorbers to allow for extended travel (so use the OEM dimensions to assist your supplier)

3. fit low profile bump stops to front suspension (OEM front shocks are reported to be OK)

4. wind up torsion bars

5. wheel alignment

I also cut the panhard rod and welded in an adjuster from a cheap adjustable panhard rod
(some say that not needed)

Others have put a spacer in the brake bias adjuster

Good post 'geoffreyKZH138V'

VanLive Northwest has a lift kit for coils. Whatever you buy, take a look there (now you know you have coils) to see how they do things.

Hadn’t thought of spacers. They will lift without any better articulation.

I think VanLife NW also have shocks. You might be able to see what they suggest, but this is perhaps a bit more complex. Most parts shops won’t be able to offer much more than stock. You might need to go to a specialist off road company? Two other things to bear in mind are that most shocks are designed for the original vehicle weight. If you’re going overland-ish and loaded toward the upper limit of the vehicle you may well want beefier shocks both for greater load absorption and also as shocks work a lot harder on gravel or rougher roads; they get very hot!

Look up the bump stops on the EPC. My 4WD has two front bump stops each side (for bottoming out). If you wind up the torsion I’m guessing these probably won’t be affected but there’s really not a lot of suspension travel at the front.

If you do change them, they are not too difficult to remove but the front most set (1 each side) have 1 fastener each that goes into a hard to access part. If you sheer these bolts they are difficult to extract ‘through’ leaving a problem.

There’s also a ‘top’ bump stop that comes into play when the suspension is maxed out (if the front wheel is off the ground). If you’re intending to lift the van then this bump stop will be nearer the median suspension level and the suspension is more likely to top out rather than bottom out. This is just a pointer. I have no advice on what to do. The OEM one is quite small and squidgy. It’s only there to prevent suspension damage when the wheel is off the ground.

The big bump stops are there to support the momentary weight of the vehicle on the chassis, when the suspension has bottomed out. With a suspension lift this is seemingly less likely (but not impossible at all).

I also think a front lift will put more strain on the torsion bars as they will twist more if / when the front suspension bottoms out. Just something to think about.

I think the front lift is probably the limiting factor on a Hiace.

The front wheel alignment seems quite complex and I’d guess this is harder on a lifted vehicle. The FSMs show a variety of diagrams with various diagonal lines for the camber and caster settings and these are predicated on a factory ride height. Step one says to check the ride height and adjust this before doing the wheel alignment. Once lifted you are going off piste (literally) and you will probably have to rely on the knowledge and experience of the garage doing the work. More to think about!

Good to mention the brake bias adjuster. I think the best way to properly set this up would be either using the pressure system method that the FSM recommends (quite complex) or with a visit to a MOT station or dynamic brake test centre that has rollers etc. You can check the system works properly beforehand (if not then sort out) and then revisit on completion of the lift to make the necessary adjustment(s). I think these options would be better than by measurement.

The measurement way would be to work out the current location of the bracket on the rear axle in relation to the underneath of the chassis then calculate the difference (greater) with the lift and transfer this to the valve lever arm. This will not guarantee the brake bias is as it should be and further adjustment will probably be necessary at MOT time.

HTH!

JT69 wrote:

Kami
I have the SC 132 Semi high roof same info on the vin plate , GVW is not given and suspect if we tow a trailer without the Gross train weight shown and axle weights shown it is illegal , I overcame this problem by having a it replaced .
     

Hi JT69.

Could you explain how you did this please?

I used a company called SVtech ltd in Leyland Lancashire just gave  them all details  they did all the research got the specs from Toyota and sent me an amended vin plate with all relevant details, costless than £200 down side they are a bit long winded at least 10 emails and phone calls but now I can tow legally . Posted on here just search vin plate , I wonder how many are towing illegally without knowing. Just google SVTech.

JT69 wrote:

I used a company called SVtech ltd in Leyland Lancashire just gave  them all details  they did all the research got the specs from Toyota and sent me an amended vin plate with all relevant details, costless than £200 down side they are a bit long winded at least 10 emails and phone calls but now I can tow legally . Posted on here just search vin plate , I wonder how many are towing illegally without knowing. Just google SVTech.

Hello JT69

Thanks for the message. I tried to pm you with my experiences but maybe you don’t have this option on?

Cheers.

Does anyone out there happen to know the exact model and part number for shocks that would be needed for a 1992 Super Custom (LH107, I think). This will be put on when I install the 2" lift from Roamer or VanLife NW.

I keep hearing about KYB, Bilstein, and Rancho 5000x - but I was looking for the exact part number so I could source them locally.

I am open other brands as well.

geoffreyKZH138V wrote:

Kami,

...........

........

I also cut the panhard rod and welded in an adjuster from a cheap adjustable panhard rod
(some say that not needed)

Others have put a spacer in the brake bias adjuster

--------------------

It has been over a year since the thread was started but I wonder how Gleasman got on.

Good to see some people mentioned panhards and brake bias adjusters. Thanks geoffreyKZ138V and LH119V. These are areas I have thought about after lifting my rear a couple of inches. I think these mods are probably necessary in a lift. I would also like to throw a couple more items into the mix: swaybars and tyre weigh.

I was going through the suspension upgrade thing but stopped a couple of years ago due to retiring and having less disposable funds. I upgraded to heavy front shocks and wound up the front a bit. I also went for heavier longer rear coil springs with a thicker spacer and heavy duty rear shocks. I also have some 215/75 BF Goodrich KA2s on it. I was considering trying to source thicker torsion bars but stopped spending money before I got too far down that track. I did not find anyone who listed heavier torsions or would entertain the thought of making them. My next step was to remove the stock torsions, do a spline count and measure the diameter and length the see if something from another model would fit. .. I would be interested to hear if anyone has found a solution to getting heavier bars.


It is my belief that with a lift there is extra pressure on the anti-sway bars and linkages also. I did not get to finding a solution but it could include longer drop linkages in the rear.

I also think when we consider heavier shock absorbers we want to improve the handling, make it firmer etc but we (read "I"! LoL ) fail to remember the weight of a larger diameter mud tyre madly swinging up and down changing direction maybe up to a couple of times a second and exerting extra leverage forces on the shock absorber, spring and pivot linkages in the process. I will be adding an extra level of "heaviness" to the next set of shocks and springs I get. I have already replaced the main pivot bushes in the rear swingarm (like motorcycle swingarms). I was going to get nolathane ones turned up but I was warned that they could possibly fail prematurely, so to use the stock rubber bushes. I am still not sure if I did the right thing but the stock rubber ones work for now. Well, that's the back end.

The front, yeah, that's a limitation alright.

A friend of mine who used to build motorbikes for off-road ‘rally raid’ races like Dakar use to describe these as:

Sprung weight / mass – the weight of the chassis etc acting on the resting axle. Loading the vehicle affects this.

Unsprung weight / mass – the weight of the wheel, hub, suspension, brake components etc that are attached by the suspension to the chassis of the vehicle. Loading the vehicle has no impact on the unsprung weight, but changing the tyre does.

HTH!!