Experience With Preparing ISUZU NPS Camper: Suspension

[whatcharterboat]

I'm surprised they recommended powerdown shockers, in the 4wd industry they don't have a great reputation.

Hi Alan, in the truck industry they do have a good reputation. We've been running them for over a year now and they're holding up well in some of the tougher applications like the oil and gas pipeline trucks. Also they're not too expensive to replace down the track. The valving is pretty close for the characteristics of the parabolic's too.

 

[Goldanfish]

Alan,
That's what they recommended now with there parabolics on Isuzu's .
I had Boss adjustables before, but only got about 60 thou.k's and 2/12 years thereabouts . 3 were leaking.
So I'll see how these go.
John

 

[IcedVolvo]

Hi People, just another quick update with a gotcha for suspension mods.

Once in while over huge bottom outs I could hear a "clang", after searching around I assumed it was the cabin moving on the moveable mounts .... well it wasnt!

What is was was the front tailshaft slider smacking into itself as it reached its limits of shortness! We currently have ATW parbolics fitted so this was happening in a standard fitting arrangement from ATW

The attached picture is of the front tailshaft after being shortened by 15mm,
and as you can see even with the shortened tailshaft the whole of the available compression slide capacity is used. Before the modificaiton the tailshaft slide was actually making contact ; hence the "clang" on big bottom outs!!.

Gibbs truck parts at Burleigh Heads QLD Aus did the excellent modification including rebalance for <$100 and a new seal was $45 from ISUZU but is a 4 week wait as it is a special order!

 

[Goldanfish]

NPS 300 Shocker Story Continues Sadly.

Continuing on from March 2014.

I fitted front and rear Powerdown shocks as recommend by ATW in March last year 2014.

They worked OK for a while. They lasted 27,447 k's to be exact.

Yes we travel on dirt roads with corrugations probably 10,000 k's of it dirt. To be very generous.
They have now all 4 of them completely collapsed.

Driving down the Sunraysia HWY from Mildura to home, (Melbourne ) the truck was almost undrivable and a danger ,with no shockers working bouncing over every undulation in the bitumen .

On returning home and removing shocks to see they were completely useless. I contacted Powderdown Shocks in QLD ,told them they were 16 months old and 27,477 k's . They said they are out of warranty can't help you.

I then contacted ATW same story, them saying we only supplied them to you and it's not our product. Can't help.

So be warned be prepared to replace your POWERDOWN SHOCKS sooner than later.
Feeling sorry I used them.
John.

 

[Mr Rehab]

John

Thanks for the info; very timely as I'm looking around now to replace the original Roboshocks fitted by ATW to my NPS. They've done almost 120,000km and I haven't had the control dramas you experienced but have been leaking oil into the air chamber almost since new so I figure time to try something else. Any suggestions for another brand?

I should add the originals were built at Yandina not by "RedRoo" who I read put some work into the seal issue.

 

[whatcharterboat]

John

Thanks for the info; very timely as I'm looking around now to replace the original Roboshocks fitted by ATW to my NPS. They've done almost 120,000km and I haven't had the control dramas you experienced but have been leaking oil into the air chamber almost since new so I figure time to try something else. Any suggestions for another brand?

I should add the originals were built at Yandina not by "RedRoo" who I read put some work into the seal issue.

Hi Guy,

How are you mate? or should I say where are you?

I know Graham has switched to a new seal manufacturer a year or two back as at one point he was having trouble with this. Why not just put new seal kits through the shocks you have. Roboshocks fitted to the big Kenworth road trains in the outback should do a million k's plus.

Let me know if you're overseas and need me to help. He lives not too far from me.

Kindest regards

John.

 

[Mr Rehab]

Hi John

Been back in Brisbane for a few weeks after 5mths in southern Europe and Morocco. Great trip despite issues with the camper (solar,LSD,fridge,roof lift) and me (broken rib, broken teeth, stomach bugs), wasn't sure who was failing faster the truck or me but all good in the end. Have to chuckle when I see guys asking is it safe to do Africa....I wasn't sure I'd survive pottering around the Mediterranean. Hoping to do Turkey, Georgia, Iran next year, if they don't blow themselves up first, hence some remedial work for the shocks.

Spoke with RedRoo about seal kits after 2013 but thought it might be worth trying Koni, they seem to have travelled well in friends trucks.

How goes the teaching? Had some much appreciated assistance from Ian/ATW when I was in Spain and Morocco to replace the failed actuator and get the roof back up. Heard you had moved to teaching. Great news.

I'll drop you a pm. Cheers. Guy

 

[IcedVolvo]

Well this is probably the last instalment on the NPS suspension saga and the suspension is about as good as it can possibly be.

It handles big G outs at 120kmh on the road and yet we have 1m+ or articulation off road. We just did about 50% of the OTL in the Cape and did not have an issue (except for scaring the crap out of myself on side slopes....would love to know what the rollover angle of this thing is but I am sure we got very very close!!). The reason we only did 50% was simply we couldn't fit past Cypress Creek in the northern end!

The final suspension modification was to the rear suspension and is something I have been wanting to do for a long time. The NPS is designed with inverted rear shackles, why I have no idea but from a geometry point of view its bad for off road stuff and it showed in its limitations. So we bit the bullet and did two things:

1: ordered a set of 1350mm parabolics (std are 1300mm) from Westralia Springs in WA and
2: swapped the shackles over so they are now drop shackles are per standard leaf arrangements

Here are the larger inverted shackles

we had to "cut and shut" the exhaust pipe to clear the shackles

Notes:
1: you will have to modify the exhaust pipe a little to accommodate the larger repositioned shackles
2: the tailshaft had to be shortened by ~10mm
3: the diff had to be wedged to keep the cv angle as straight as possible

The result is probably the most comfortable and capable off road NPS around (barring the coil conversion of course!).

If I was to do anything further it would be to:

1: reposition the rear shockers further outboard (they are very inefficient in their current position) and move them to the rear of the diff as they are very vulnerable where they are

2: add a second set of front shocks to allow more adjustment for on/off road differences

Thanks to Westralia Springs (http://www.westraliasprings.com.au/) for being the only Aussie manufacturer of parabolic springs! These springs are really really good!! We just pounded the crap out of them across 7000km in the Cape! Keep up the good work guys (PS if you order use a carrier other than Northline as we were continually misinformed about delivery date).

A very special thanks has to go to Steve Tucker from Tucker Suspension on the Gold Coast (http://tuckersuspensions.com.au) as he has persevered and helped me throughout the long process of turning the originally almost undrivable NPS into a comfortable and very capable off road beast.

 

[DzlToy]

More than a meter of articulation on an NPS? That is impressive.

It certainly would not hurt the OEM's one bit to put just a bit of effort into making these things ride more like an HD a pickup truck or van and less like an ox cart.

How much tuning did you do with the dampers, versus working with manifacturers to create a system based on weight, driving style, tire/wheel combo, etc?

Cheers

 

[grinch]

John

Thanks for the info; very timely as I'm looking around now to replace the original Roboshocks fitted by ATW to my NPS. They've done almost 120,000km and I haven't had the control dramas you experienced but have been leaking oil into the air chamber almost since new so I figure time to try something else. Any suggestions for another brand?

I should add the originals were built at Yandina not by "RedRoo" who I read put some work into the seal issue.

Probably too late, but your robo shocks are completely rebuildable to be like new again, Graham is still going in yandina, we use his suspension in our off road race truck and we can not fault it, i can get you his details if you need.

 

[nikpo]

The title sort of says it all but if people are interested I will start a series of threads on my experience with setting up an ISUZU NPS four-wheel-drive truck as a serious off-road camper. I'll use the same title but change the end word to address each of the general areas that we have come across.

Firstly let me say that we purchased the basic unit from All Terrain Warrior on the Sunshine Coast in Australia but I am not employed by them nor do I get any commissions or other financial gain. Unfortunately we could not afford to purchase the "bells and whistles" version of the Scout so we have had to do a lot of setting up and problem solving ourselves. Having said that I can thoroughly recommend All Terrain Warrior if you are considering one of these styles of vehicles.

By far and away the biggest problem we had to solve was the issue related to suspension. If we had the money we would certainly have engaged ATW to carry out either the coil conversion they are now doing or some sort of extended leaf set up. However doing this on the cheap has given us a real insight into how the suspension on trucks works and the problems, particularly in light trucks, of the unsprung weight of the heavy front axle versus the overall weight over the front axle.

When we first took delivery of our truck it was fitted with the standard springs and shock absorbers front and rear. The NPS is a six tonne rated truck but only weighing just over 4 tonnes as delivered. The suspension was so bad that my wife cried all the way home and both of us were shaken to pieces by the horrendous ride on the trip home. I consoled her in the knowledge that we could make the suspension a lot better. However I needed the assistance of a good friend of mine who owns a truck suspension company on the Gold Coast in order to do a lot of trial and error testing.

I will cut a long story short by telling you is simply that we have tried all the traditional fixes that one would normally try in a cab over situation. In the end we found the following things dramatically improved the ride to the point now where the truck is almost car like in suspension.

Front Suspension:

1) we modified all the hinges from the standard 19mm rubber bushes to 25mm greased pins and shackles.

2) We obtained a 1300 mm x 70 mm parabolic spring pack from another truck. Unfortunately we do not know exactly what truck these springs came from as although brand-new I found them at a wreckers; but I suspect they came from the front of a 2009 Hino 500 series.

3) We fitted a set of Boundless Rider fully in cab adjustable air shock absorbers

4) although it might not seem relevant it actually made a significant difference in the front suspension by fitting a substantial rear towbar which carries the two spare wheels. The total all up and weight of the towbar and spare wheels is ~300 kg and although I'm not sure it's exact reason I theorise that by adding a static weight to the rear of the truck acted like a counterbalanced pendulum which inhibited the front of the truck from moving up and down so readily.

5) we modified the wheels from the standard 17.5 to 19.5 inch super singles with a 265/70 tyre fitted. Although when we can actually manage to obtain a set 285/70 these will be the standard tire we fit to this vehicle (someone who shall remain nameless has purchased every tire in Australia of this size!).

6) we have had both a caster and camber kit fitted to the front and which although probably hasn't had much effect on the suspension itself it has dramatically improved the handling particularly during undulations in the middle of corners.

All up this has cost us about $3000 which although not cheap is far less expensive than the $10-$12,000 for the OEM conversion by ATW.

The next step we are going to take is to remove the third leaf from the parabolic spring pack to see if this makes the front a little bit more compliant but to be honest I think it's about as good as we are going to get it for the reasons I alluded to above; the simple fact that the unsprung weight of the front axle is a significant proportion of the total weight of the front end. As a result although will we handle compression bumps quite well drop aways or decompressions are always going to be a problem. it will be interesting to see what if any difference the fitting of a 200 kg bull bar/winch combination to the front-end does. I'll update this thread sometime later in January next year to let you know what the outcome was.

Rear Suspension:

At this stage we are only just starting down the track of getting the rear suspension correct. Because our vehicle only weighs about 4.3 tonnes we found the rear end was bouncing when we went over speed humps so we had the auxiliary spring pack removed and the main springs slightly reset so they work a little bit more. Although this has dramatically improved the rear ends ability to articulate and for comfort purposes it has also detracted a little bit from the handling of the truck as it tends to roll a little bit more in corners.

We are sort of in limbo with respect to the rear end, when we add some extra weight to the front next year we'll see what happens and if the rear suspension is reasonably satisfactory I will simply purchase another set of those stunningly good shock absorbers made by Boundless Rider and fit them into the back. Failing that I will probably go back to ATW and ask them to do that really nifty coil conversion they have been working on but I might have to take out a second mortgage on the house and sell one of the children for medical research

The only other thing you need to consider is the use of some sort of detachable sway bar for off roadwork (note the rear of the NPS does not have a sway bar fitted as standard). If you take the front sway bar off on the road the truck rolls around far too much especially on high speed highway conversely the sway bar is way too stiff to allow proper articulation in off road situations. I am simply going to replace the existing nuts and bolts on the bracket with a wingnut/split pin set up so that I can quickly remove the sway bar when I go into any sort of serious off-road situation.

Great information.
How did you convert to super singles plus all the other mods for $3k?