Caravan pushing my Pajero side to side, will air suspension fix this

[old Jack]

Whilst I suspect it is mainly a caravan issue I would not discount anything, hence the questions on ride heights. Could be one or more of the following.

1. Pajero rear tyre pressures too low.
2. Pajero rear coils too soft.
3. Pajero broken rear sway bar link.
4. WDH not setup correctly.
5. If dual axle is load sharing leaf suspension then towbar is too high for tow hitch.
6. Caravan loading is not optimal for this particular caravan.
7. Caravan design is too rear heavy.

OJ.

[Nab]

Pajero’s rear shocks faulty? Shouldn’t be on a 2018 Paj though

[old Jack]

Pajero’s rear shocks faulty? Shouldn’t be on a 2018 Paj though

Never say never, I have seen them fail by 30,000kms.

OJ.

[2bad4u]

I'm an advocate for the use of an WDH in most situations, but based on the information provided I would be seriously reconsidering it's use in this situation. With a relatively light tow ball weight already you could be removing / shifting too much weight away from the tow ball. I would try removing the WDH and see if that improves things. Or at the very least, try reducing the amount of tension you are placing on the WDH.

Also check the loading of your van. Heavy items low and central (over the axles) and light items higher up and front / back of the van.

The Pajero (or it's suspension) isn't the problem, it's the setup.

Edit: Have you got the right WDH? I've come across people who don't realise there are different variations / types http://www.haymanreese.com.au/produc...bution-systems

[TC.Barky]

Sounds like unbalanced loading on the van to me.

If not, I'm a member on a caravan/trailer brand specific group and they get this issue reported a fair bit with the bigger hybrid vans. Usually putting the caravan tyre pressures to some huge figure like 50PSI fixes it for them.

[nj swb]

I'm a member on a caravan/trailer brand specific group and they get this issue reported a fair bit with the bigger hybrid vans. Usually putting the caravan tyre pressures to some huge figure like 50PSI fixes it for them.

Is this a Pajero specific problem, or does it affect more vehicles?

[TC.Barky]

Is this a Pajero specific problem, or does it affect more vehicles?

Multiple vehicles

[Ian H]

It may not be a solution but many years ago, when we were allowed to drive out of caravan dealers pulling a heavy 18' Viscount van with nothing more than a Falcon wagon, I had severe wobbles until I fitted a WDH and changed the btyres on the van. Initially it only had normal road tyres so it was prone to swaying because the side walls of the tyres weren't stiff enough. I put on some light truck tyres, pumped them up to 50psi, added the hitch and it towed well. Of course, taking the heavy annex off the bed and placing it over the axle on the floor also helped.

Knowing what I know now about vans and weight, I go cold thinking about those days.

[Travis73]

If your tyres have a max PSI cold pressure stamped on them, pump them up just under it.
Look at light truck tyres for your Paj and the van. They have a stronger sidewall an when pumped up will offer less flex.

[Merts]

If your tyres have a max PSI cold pressure stamped on them, pump them up just under it.

With respect, that's not good advice. Depending on the tyres you could be inflating them to twice the required pressure for the actual loads.

You should only inflate to the maximum pressure if your axle load is approaching the load limit of the tyres. If you are running LT tyres you are likely to be well under the load rating of the tyre. Excessive inflation will result in uneven tyre wear, poor handling and braking, and an unnecessarily rough ride.

[old Jack]

Agree about not inflating the tyres more than the load carried dictates. You are likely to cause yourself other problems with the caravan if you run with tyres that are too hard, like wheel bearing failure, tyre tread cupping, accelerated shocker and shocker bush wear, suspension and structural fatigue and reduced caravan brake efficiency.
Sure it might improve the symptoms of the swaying but it has not fixed the underlying cause of the problem.

I suspect many people that have this problem just ignore it or live with it because they do not want to make the major changes required to solve the problem.

OJ.

[2bad4u]

Right or wrong (don't shoot me down) but I use the following as a starting point for tyre pressure:

Assume the following, and this is very simple maths, if you have a dual axle caravan that weighs 3000kg then in theory each wheel is carrying 750kg (forgetting sharing or non load sharing suspension). Then if your tyres are rated at 80psi @ 1000kg then you are working on 75% load (750/1000kg) so inflate your tyres to 60psi (75% of 80psi).

This forms the starting point, then work on the 4psi rule to refine your pressures. Using this method has worked for me and usually results in only minor adjustments once I apply the 4psi rule. Interestingly the adjustments have always been down from the starting point and never up.

Edit: This may be useful ===> https://www.coopertires.com.au/media...-pressures.pdf

[old Jack]

Rather than guess what the minimum cold inflation pressure is for a given tyre size and load, just look it up in Lod Inflation Tables.
Below is the link to the Toyo tables but this can be used on all brands of tyre's, loads are in lbs so just divide the load by 2.2 to convert to kg.

https://www.toyotires.com/media/2125/application_of_load_inflation_tables_20170203.pdf

OJ.

[Nab]

Cheer OJ, that is great info! I run the AT2 on my Ranger, according to that table I should be at 45-50psi in the rear, I have been running 48psi as it "feels" right, either a fluke or I have a 6th sense hahaha!!!

[erad]

I have tyre pressure monitors on my caravan. I also have LT tyres on the van and the 4 psi rule does not apply. I always get at least 6 psi increase from cold to warm. I kept raisin the pressures to try to get 4 psi, but still it went up by 6 psi. Initially, I started at 40 psi, and each day increased the pressure a by about 5 psi. Still the 6 psi cold to hot increase came up. Finally, at about 55 psi, I had a wheel bearing fail, so I am going back to about 45 psi. The wheel rims are fairly narrow, and the tyres look baggy at 40 psi, but even at 60 psi (hot) they still look baggy, so that is not a way to choose optimum pressures either.