GU Suspension Failure

check out here, http://forum.patrol4wd.org/phpBB2/

it has been reported before.

Back a month or so, someone posted a similar and a few responded with the same problem, so yes it has been a problem. Maybe with just a certain batch of vehicles

yes,
reasonably common, and a carry over problem from the GQ, which bent up, but the GU seems to crack them.

the outer edge of the spring bracket needs support, and can be done with a steel brace across the chassis over the top of the spring mounts.

This stops them bending up and tap tap tapping on the floor as they start to go ;-)

It's quite common and more so when you use heavy duty coils. Think about it, if the spring is stiffer and not compressing then something has got to eventually give. The stock springs probably wouldn't cause a prob as they are light and soft.

Leroy

tolch

I have heard all of these stories before, starting with the rear suspension spring towers in the GQ, and now with the GU, and I used to be paranoid about the same thing happening to my vehicles, but over the 12 or so years, I have had Patrols, with 3 years living and travelling constantly out of Alice Springs, have never had any problems at all, but I have always had the right suspension setup for the right application.

When I bought my latest Patrol, I talked to all the suspension blokes about their recommendations and setups for heavily loaded vehicles.

According to my local suspension expert, the only time the spring towers present a problem with breaking mounts and the like, is when you use Polyairs or the equivalent product, with heavily loaded vehicles, as it prevents the spring from taking the shock load from the constant pounding of the suspension, and thus the shock load is then transmitted to the top of the spring tower, in turn causing it to break.

This normally rears it's head with cab chassis vehicles, as they more often are heavily loaded than wagons.

I asked my suspension expert whether polyairs, or their equivalent products, were worthwile getting installed, for my latest application.At the moment, I often travel lightly loaded for my work, but load up for the weekends, and I received a resonding NO.

In short - get rid of the polyairs, and get the right springs for the job.

Regards
Mic

Which brings into play another factor which is the total weight of the vehicle (GVM)when it is loaded with all your accessories, equipment, fuel, water and passengers for the trip in question.
If it is over the GVM as stated by Nissan then they are not liable, it is you the owner who has exceeded the stated design parameters, voiding the warranty and probably your registration and insurance.
I'd hazard a guess that nearly 100% of 4wd stationwagons that are loaded and on outback roads in holiday periods would be laden in excess of the GVM when leaving on long trips in remote areas.
The ones with camper trailers on the back off the bitumen are probably also exceeding the off road towing capacity of their vehicle as well.
Manufacturers towing capacities are usually for bitumen road/good smooth dirt only.

Hi Tolch
I have a GU with heavier (but not the thickest available) back springs fitted as well as Polyairs and have not had a problem. Discussed it with the Nissan dealer before fitting. One of the problems is that some of the spring setup are too thick so the when spring compressors it becomes solid as the axle comes up before the bump stop comes into play, this put extra pressure on the spring towers. We have travelled 60000klms many of them off road with the camper on with no problems. I have 15lb pressure in the polyairs.
Ray

As an observation only, the whole thing must be all about loadings as several contributors have said - just what can the spring mount be exected to withstand ? There must be a reasonable limit - assuming that 2/3 of a trip load goes on the rear of the car, re-rated springs might be the best idea - polyairs don't actually do the same thing far as I can see. On the fuel component, one bloke in this forum was talking fuel tank combos around the mid 250 L I think - if all the other trip gear goes in, and most of the extra is born at the rear, can the suspension be expected to cope ? I'm prone to taking a lot of "just in case" crap with me - I choose the camper trailer option - allows me to spread the load across 6 wheels. I reckon there is merit in the idea to forget fuel pricing, and just have a capacity to do the town to town jumps.......carrying excess fuel for price advantage might be costlier, re tyres etc.

Perhaps one additional thought. Many also pump up their tyres to quite high pressures, to compensate when they’ve overloaded their 4WD . Tyres contribute to the suspension and overly high pressures will add to the strain that the suspension will have to cope with. So with a combination of very stiff suspension, overloading and high tyre pressures, is it any wonder that something eventually gives?

I had the same prob as you . Made up a couple of brackets that go down from the tray to the outside of the tower and give it some suport . Havent had a prob since i did it and its dun a lot of offroad Ks .I still keep a check on it through . If you,r around Perth , you could take a drive up up here and take a look at what i did to get some idea,s . Cheers.

Tolch

I had a problem of towers pushing up at 13k kms ans so had Nissan push or belt them down. Belted I think, was under warranty but I then had a 1/2" by 8" plate over the top of the towers side to side and bolted into place. I took some photos of the plates when they were new and can forward them but you would need to strengthen the tower too after getting it back to place. If you wanted a copy my email is with the rig pic.

I had Polyairs on from new and have since fitted heavier springs too but really the combination of exceeding GVM and speed over rougher conditons will provide the problems. You may not even need to exceed GVM - just be up close with high speed.

As to what is not progressive in a Polyair against a progressive rate spring? I would say nothing - as you have a higher weight on already and the progressive part of the spring is already compressed and taking the higher shock load into the spring tower.

I have seen this problem but only on vehicles that were loaded way above GVM. Doubt that Nissan would warrant this as it is caused directly by overloading. I strongly agree with the theory that polyair make the problem worse, as you go on full compression they will place a massive load on the towers rather than the constant rate load that heavy coil will.

Everyone see to be happy to ignore the fact that vehicle do have a rated GVM and that is supposed to be the max. legal weight for the vehicle. Sure you can safely run a vehicle above this figure but can anyone tell me at what point you cross the line to be excessively overloaded!