Technical 2019, 2.3 , 150 campervan front suspension issues

[Chadz]

The front end geometry has serious issues.
Front tyres hae worn down to < 3mm from new, within 15,000 kms. But even wear ?
The springs have the usual sag with only 750 mm measured to the wheel arch.
There is also the typical violent crash on the bump stops when any road bump or pot hole is crossed
I have tried 3 different suspension shops to get the allignment check and reset, but without luck since there is excess negative camber ( which cannot be adjusted) and none of the shops will do anything until i get the camber fixed.
My own crude but repeatable camber measurement suggests 10-15 deg negative on the driver side, and much more , 15-20deg on the passenger ( left) side. .??
At the same time there is at leas 15+ mm toe in !
Whilst this is a high milage (240k, kms) ex rental, its service records suggest new struts, ball joints, etc were fitted at 220k kms, and they do look recent.
What could be causing this excess negative camber ? …struts not installed correctly
A plan on the increased height Kings springs, but need to understand what else may need replacing
Sugesstions on good mechanics in southern NSW also welcome !

 

[bugsymike]

On some vehicles if top strut in wrong at top mount it will affect camber/angle of strut leaning in or out.
Excessive Negative camber usually means the top of the wheel is in towards the centre of vehicle/engine, this also means the inside edge of tyre wears most.
Before the advent of power steering it would also increase the tendency to "self centre" the steering after cornering, much the same as too much "toe in" although that tends to wear the outside edge of the tyre.
Apart from all that what tyres have you got on, heavy duty tyres with more side wall plies tend not to move around so much and last longer, but often have less wet weather grip etc. So check the load rating of the tyres according to your owners manual etc.
Another problem I have found is most MHs tend to spend their entire life overladen which makes the problem worse.

 

[Chadz]

Hi Mike, Yes i thought the same, but with the amount of negative camber i have here, i would need to move the top of the strut outwards at least 25-30 mm to get the wheel near to upright.
Can a wrong top strut mount really make that much difference ?
..could a strut (both ?) be bent to cause the problem ?
Tyres are commercial light van tyres. @ 65 psi .

 

[deejays]

The front end geometry has serious issues.
Front tyres hae worn down to < 3mm from new, within 15,000 kms. But even wear ?
The springs have the usual sag with only 750 mm measured to the wheel arch.
There is also the typical violent crash on the bump stops when any road bump or pot hole is crossed
I have tried 3 different suspension shops to get the allignment check and reset, but without luck since there is excess negative camber ( which cannot be adjusted) and none of the shops will do anything until i get the camber fixed.
My own crude but repeatable camber measurement suggests 10-15 deg negative on the driver side, and much more , 15-20deg on the passenger ( left) side. .??
At the same time there is at leas 15+ mm toe in !
Whilst this is a high milage (240k, kms) ex rental, its service records suggest new struts, ball joints, etc were fitted at 220k kms, and they do look recent.
What could be causing this excess negative camber ? …struts not installed correctly
A plan on the increased height Kings springs, but need to understand what else may need replacing
Sugesstions on good mechanics in southern NSW also welcome !

My suggestion: Get some new ALKO front struts fitted by a reputable installer and go from there. The ALKO will give you an increased ride height of 40mm, with increased spring rate and matching damper. It will overcome the crashing issue on potholes you have now. Then if the alignment is still incorrect, at least you can discount the strut and go looking for the issue.. But sounds like bent kingpins to me to get that much negative camber.

 

[bugsymike]

Hi Mike, Yes i thought the same, but with the amount of negative camber i have here, i would need to move the top of the strut outwards at least 25-30 mm to get the wheel near to upright.
Can a wrong top strut mount really make that much difference ?
..could a strut (both ?) be bent to cause the problem ?
Tyres are commercial light van tyres. @ 65 psi .

On some top strut mounts they are eccentric to the spring cup so if swung around into the bolt holes out of their correct position they will move quite a lot.
As @deejays mentions a known good quality strut fitted by a trusted dealer would be a good starting point.
Re the tyres "commercial light van tyres"? I would check the load rating on the tyres and compare your actual loaded vehicles weight on a weighbridge to see if there is a enough margin.

 

[Chadz]

sounds like bent kingpins to me to get that much negative camber.

Is there such a thing as a “king pin” on a front wheel drive/ macpherson strut suspension set up ?
Is therea diagram of these components somewhere ?
I could fit new struts ( current ones are less than 9 months old ), uprated springs, new top strut mounts, etc, ..
Maybe new lower ball joints ?…but they were also replaced last year !
Or, lower wishbones/bearing hubs ?
Thats a costly way to solve the problem … and what if that still doesnt correct the camber ?
This is my problem….Finding a honest mech to check it over and find out exactly what is wrong.

 

[deejays]

Is there such a thing as a “king pin” on a front wheel drive/ macpherson strut suspension set up ?
Is therea diagram of these components somewhere ?
I could fit new struts ( current ones are less than 9 months old ), uprated springs, new top strut mounts, etc, ..
Maybe new lower ball joints ?…but they were also replaced last year !
Or, lower wishbones/bearing hubs ?
Thats a costly way to solve the problem … and what if that still doesnt correct the camber ?
This is my problem….Finding a honest mech to check it over and find out exactly what is wrong.

King pin/stub axle, - call it what you like - possibly stub axle is correct - the axle the front wheel rotates around. They only have to ben a little to give a huge negative camber. Ok, then if money is tight - and I get it - no use just replacing good parts. Check the clearance between the wheel and the strut and compare it to a good Ducato - that will answer the question for you.

 

[bugsymike]

Unlikely to be bent suspension both sides the same amount.
More likely either wrong parts or parts wrongly /badly fitted.
With Mcpherson strut suspension generally you replace that with it's shockabsorber centre part as a unit and spring, below that is the bottom wishbone arm with a ball joint that sits in hub bearing carrier area.
Any physical damage to the wishbone should be fairly obvious I would have thought and may be checked with a tape measure, plus also width to outside of tyres at road compared with the rear wheels assuming not Alko rear or twin wheel etc.
In the absence of anything else obvious my thoughts are towards the top strut mount fitting.

 

[Chadz]

King pin/stub axle, - call it what you like - possibly stub axle is correct - the axle the front wheel rotates around.

I know what you are trying to say, but again, on a front wheel drive system the “stub axle” rotates with the wheel,.. which would result in a massive wobble if bent .
So i am again thinking bent strut where it connects to the whell hub unit.
Has that been seen before ?
Note:—the negative camber is different on each side (see first post)
Notr2:—Data from google suggests that the total compression/extention travel on a standard strut is 185 mm (?)
On my set up, the strut compresses 126mm from unloaded to normal ride height.
That suggests there is only <60mm remaining compression travel to adsorb bumps or additional load (fuel etc)
So i am concluding the need for new, taller, springs is essential ?

 

[deejays]

I know what you are trying to say, but again, on a front wheel drive system the “stub axle” rotates with the wheel,.. which would result in a massive wobble if bent .
So i am again thinking bent strut where it connects to the whell hub unit.
Has that been seen before ?
Note:—the negative camber is different on each side (see first post)
Notr2:—Data from google suggests that the total compression/extention travel on a standard strut is 185 mm (?)
On my set up, the strut compresses 126mm from unloaded to normal ride height.
That suggests there is only <60mm remaining compression travel to adsorb bumps or additional load (fuel etc)
So i am concluding the need for new, taller, springs is essential ?

As I originally said, replacing the struts with uprated ALKO units will fix your suspension travel issues. I threw out brand new front struts on a new Ducato, complete with springs and replaced them with the ALKO uprated units - no more crashing on bumps and superior handling all round. You are correct in what you have said about the stub axle - my mistake - yes the tube of the strut may well be bent. But you should be able to clearly see that, or as I said measure the rim to strut clearance. If you cannot find the issue yourself, then a decent FIATPRO workshop or suspension specialist soon will.

 

[Chadz]

On some top strut mounts they are eccentric to the spring cup so if swung around into the bolt holes out of their correct position they will move quite a lot.

I understand that the Ducato topmounts are specific to the Left and Right side and have a very uneven bolt patern.
Is it actuall possible for these to have been fitted either on the wrong side, or even rotated out of correct position.?
It looks unlikely from the component pictures

 

[deejays]

Sorry but I cannot confirm. I had the job done 6 years ago by Southern Euro in Melbourne - a FIATPRO dealer. 10 to 20 degrees negative camber is more than you would run on a race car - ridiculous. And 15mm toe in - insane! Was the vehicle like that when you bought it, or has it happened during your ownership?
It would not be roadworthy as it is. If you cannot spot the issue yourself, then I suggest you get it to a FIATPRO workshop or a suspension workshop that knows what they are doing. But, if it is out by that much, it should be (screamingly) visually obvious.

 

[bugsymike]

I understand that the Ducato topmounts are specific to the Left and Right side and have a very uneven bolt patern.
Is it actuall possible for these to have been fitted either on the wrong side, or even rotated out of correct position.?
It looks unlikely from the component pictures

Looking at the photo, would it be possible N/S has been fitted on O/S and vice a versa?

 

[Chadz]

Looking at the photo, would it be possible N/S has been fitted on O/S and vice a versa?

That was my thought also,
But without detailed component drawings, or direct fitting experiance, it seems very unlikley when looking at photos ofthe part ( assuming these are the correct parts for my year/ model)
The strut center is certainly off center to the mounting holes, but the locating bolts are not symetrically spaced and there appear tl be locating pins to position it correctly into the chassis.
Also, for this to be a likley cause, that strut center would need to be 40-50 mm out of position, and that does not look possible from a wrong fitting.
I am begining to think the issue is more likely to be bent struts .

 

[deejays]

That was my thought also,
But without detailed component drawings, or direct fitting experiance, it seems very unlikley when looking at photos ofthe part ( assuming these are the correct parts for my year/ model)
The strut center is certainly off center to the mounting holes, but the locating bolts are not symetrically spaced and there appear tl be locating pins to position it correctly into the chassis.
I am begining to think the issue is more likely to be bent struts .

If it is bent struts, then with the degree of camber you are quoting it should be really obvious to see. As I said earlier - measure the gap between the inside rim and the strut and compare to a good vehicle.

 

[GraceWillow]

First thing I'd check is the tyre pressures. Dealers often leave them at the max van pressure, not the lower pressure recommended for camper conversions. Could be a much cheaper fix!

Also worth confirming what shocks are on there now. As others said, they might be Sachs already, just the standard ones.

 

[bugsymike]

If it is bent struts, then with the degree of camber you are quoting it should be really obvious to see. As I said earlier - measure the gap between the inside rim and the strut and compare to a good vehicle.

It certainly needs a good inspection by a qualified motor engineer.

 

[Anthony489]

Hi Chadz

The way your describe your van's suspension sounds quite alarming.

If the tyre diameter is 700 mm, a 15 degree negative camber would mean the top of the tyre would be leaning out by a massive 182 mm and the strut top would be out of position by even more. I don't doubt your van has an alignment issue but I suggest you re-check your calculations. Manufacturers tolerances for such angles are in fractions of a degree. I am aware of camber adjustment bolts (eccentric bolts) for some models, but the adjustment range is of the order of millimetres.

Negative camber will cause tyre wear on the inner edges, and toe-in will cause wear on the outer edges so maybe they even up !

I would expect a standard loaded Ducato to have a suspension frequency of about 1.6 Hz, which implies a static deflection (from no load to settled) of 100 mm at the wheel. I don't know the leverage ratio between wheel and spring, but for a Macpherson strut it's close to 1 so I'd also expect a spring deflection of 100 mm. Your 125 mm sounds too much, so as you say it limits upward travel and means the bump stops are contacted much more frequently than they should be. The spring stiffness must be chosen to suit the normal running load on the front wheels, either a weighbridge or a calibrated brake test bay will tell you this.

Bear in mind that Fiat produced both light and "maxi" chassis with different suspension components, so it's possible to get the wrong parts.

It's hard to tell from my armchair thousands of km away, but I suspect either the wrong components have been fitted, there is an assembly error, or the vehicle has been "jumped" off a big drop and something has got bent.

Good luck in your quest !

 

[Chadz]

If the tyre diameter is 700 mm, a 15 degree negative camber would mean the top of the tyre would be leaning out by a massive 182 mm and the strut top would be out of position by even more.

Sorry, yes my calc was incorrect.
I measured at the rim, top and bottom,.. 60mm approx difference.. top of wheel leaning IN not out.
Rim dia is 420 mm…so i think that suggests 8 deg negative
Still way too much , and beyond any correction at the top of the strut.

 

[Chadz]

It certainly needs a good inspection by a qualified motor engineer.

Agreed, but this is the biggest issue with these vans.
Finding a good mech eng with any experience on them and prepared to do the work, isa very rare thing in Australia.
The nearest Fiat service center to me is 2+ hrs away, and doesnt seem too willing to check this out.
I have tried unsuccessufully with 4 separate mech shops to even get a basic allignment check, let alone prepared to rectify the problem. I seems service shops have enough demand to choose what ther want to work on.
Fiat are just not well supported here.