air bags

beehive · Veteran Member

air bags

Haji-Baba · Senior Member

Behive

I would suggest you do a lot of homework before fitting air bags to any rear leaf springed vehicle.

A lot has been said on this and other forums re: air bags. Bent chassis and damage to vehicles.

I would seriously question the advice you have received about air bags.

Also $1700.00 seems a lot for fitting two airbags.

Have fun Haji-Baba

KFT · Guru

I had ARB Tamworth fit OME 400kg constant load rear suspension to my Navara D40. cost around $750

best thing I could have done. rides and handles better and now sits level with my 2.9 tonne van on the back and all the gear in the tub.

frank

PeterD · Guru

beehive wrote:
I am told i need a heavy duty hayman reece tow bar and air bags fitted also.

bent chassis.jpg

This is the thing that is likely to happen when you fit air bags and put a lot of weight on the rear. The picture is not of a D40 however the problem is not brand specific. The problem is that the chassis are meant to take the rear axle stresses on the spring hangers. Air bags are not linear in their spring rate, as they compress they get very hard. When you install them above the axle they place stresses on the chassis in a place that was not designed to take stresses. As the rear wheel thump down into a rut or go across a cattle grid they thump up through the air bag, which by the time they are near full compression place nearly the whole loading on chassis and cause the chassis to bend because of the unusual loading. Add air bags at your own peril.

Nissan do not warrant the use of WDH on their tow bars. The fitting of the HR bar is a good move. If you use WDH with them HR will carry the warranty - provided the vehicle is not modified and the chassis is as they did their engineering analysis of the tow bar mounting.

I have a D40 and tow a 5.5 metre van. I have no need of a suspension upgrade. The only requirement for suspension upgrades would be for supporting an overload. If your WDH has been installed and adjusted correctly then the loaded trim of your vehicle will be similar to what it would have been had you placed the load of the tow bar in amongst your stuff in the tub.

rockylizard · Guru

Gday...

Lots of pics of bent chassis here - https://www.google.com.au/search?q=dual+cab+ute+chassis+bending&biw=1366&bih=643&tbm=isch&tbo=u&source=univ&sa=X&ei=vn5tVNfMApeIoQTntoEI&ved=0CDsQsAQ

Google "dual cab ute chassis bending" ... and you will find the large number of forums where this is discussed and examples provided.

Cheers - John

Aus-Kiwi · Guru

You'd be a wan ker to do that damage ! What where other factors involved ?
Don't use the air bag as a bump stop! Don't pump them up to level weight still needs to be on springs..

Brenda and Alan · Guru

Looking at PeterDs' pic compared to most of those in Johns link I would suggest the more likely cause was a WDH not air bags as the bend is in wrong place for air bag damage.

I would fit Nissan's own towbar and forget about any suspension mods, if the back of the ute. sags to much with van attached it then becomes Nissans problem as they sell vehicle as being able to tow 3500 Kgs.

(approx 350 Kgs tow ball load)

Alan

Jaahn · Guru

PeterD wrote:
beehive wrote:
I am told i need a heavy duty hayman reece tow bar and air bags fitted also.

WOW WOW

That picture would make me seriously look at the total load I was putting on any vehicle I owned. Perhaps it is time to leave some stuff behind and travel light. How much stuff do you need on the road ????

jaahn

beehive · Veteran Member

Hello and thanks for the info I have decided to go back to the Nissan dealer and have a chat about all options.Cheers beehive.

beehive · Veteran Member

Hi airbags and towbar for that cost.I am going to go to NISSAN and have a chat with them tomorrow,cheers beehive.

beehive · Veteran Member

Hello and thanks for that info. I am going back to see the Nissan guys tomorrow morning,cheers beehive

beehive · Veteran Member

Hi yes your not wrong,i wont be going off road nor will i tow way outside the vehicles limit,cheers beehive

beehive · Veteran Member

Hello,I get you,I am off to see nissan guys tomorrow morning to chat about my problem,thanks for your comment,cheers bedhive

beehive · Veteran Member

Hello,I will google the site you advised,thanks beehive

PeterD · Guru

Brenda and Alan wrote:
1. Looking at PeterD's pic compared to most of those in Johns link I would suggest the more likely cause was a WDH not air bags as the bend is in wrong place for air bag damage.
2. I would fit Nissan's own towbar and forget about any suspension mods, if the back of the ute. sags to much with van attached it then becomes Nissans problem as they sell vehicle as being able to tow 3500 Kgs (approx 350 Kgs tow ball load)

1. I am yet to see one of these bent vehicles that has had WDH fitted. There will be two bends in that chassis, one near the B pillar and one under the front of the tray. The bends are all caused by the the excessive weight in the tray and on the the tow bar. All these vehicles seem to have been towing heavy ball weight camper trailers (heavy because they stack fridges and water on the drawbar.) A common factor of all vehicles is they are designed to be loaded with the weight spread across the whole passenger and luggage space. These out back travellers who bend their chassis have the majority of their weight in the tub and on the ball.

If anything if you have WDH fitted it would tend to counter the heavy tear loadings. Remember, they twist the chassis up, not down.

2. The D40 is only rated to 3000/300, not what you suggested. Nissan has not gone down that high tow load race.

PeterD · Guru

beehive wrote:
Hello and thanks for the info I have decided to go back to the Nissan dealer and have a chat about all options.Cheers beehive.

Nissan will simply tell you they do not recommend that you fit WDH to their tow bars and leave things at that. Friends and other forum members have been there and done that. They may or may not refer you to the de-rating table for ball weights in your handbook.

Nissan D40 GVM reductions with ball weight.GIF

Here is the table again for you. I have a canopy and a protection step (which is heavier than a tow bar) fitted to my D40. In the thread - http://thegreynomads.activeboard.com/t58956227/making-caravans-stable/ - at Date: 23:21 Nov 14, 2014 I posted some figuring showing how much weight capacity I have left after I have loaded it with full fuel and the navigator (and myself.) That also showed that if I did not have the WDH I would have SFA capacity left for bulk food, booze and camp furniture in the tub.

If you don't have WDH then you will loose capacity in the tug. I would keep away from Nissan. Go and see a Hayman Reese agent. They warrant the use of WDH on your vehicle even if the manufacturer will not. Without using WDH you will be severely limiting what you can carry in your tug.

-- Edited by PeterD on Friday 21st of November 2014 09:48:41 AM

Aus-Kiwi · Guru

Have (on the quiet ) repaired a Mazda chassis which was bent , not as bad as above..
It was involved in an accident with approx 2t load trailer ..
No mods where done to suspension..
It seems the heavy braking and front on impact was enough to bend chassis..
This model is just superseded now , it's said that the chassis is stronger on the newer model..
Chassis was fixed by pulling down to straiten then we BOXED the chassis.. It was bent I front
Of rear suspension. So I assume weight ON vehicle didn't have much to do with it?
The inertia of the trailer even though it had brakes compounded with accident..
There was much structural damage to the front.
We are using these light trucks where we used Patrols and Cruisers in the past..
I would be looking at medium weight truck second hand for same price .
Then up grade your licence .. Which seems the reason why these light trucks are used..
Btw the repaired Mazda is still driven daily by the original owner , goes and dives as good as it's ever done...