strut, alignment and tire wear

[benben]

Hi everybody,


I bought a 2006 xc90 D5 2.5l about a year ago. After 3 months I changed the passenger front strut, it was way worse than the other 3 for some reason. All was well, a few months later I put on 4 new tires and had a 4 wheel alignment done. Soon after I noticed the passenger tire was wearing excessively on the outer edge.

I took the car back for alignment, this time I watched the whole process and the camber was off by 2 degrees positive (top out). The caster angle is also 1.9 deg lower than spec. The tire shop told me they couldn’t adjust either.
The camber on the drivers side is off by 1 degree in the other direction(top in), but that doesn't worry me.

I filed out the adjustment hole on the strut and got the camber where it’s supposed to be but the caster is still way out.

I don’t recall the old tire wearing badly before I changed the strut but I'm not sure. The old tires were pretty bad overall.

I'm a bit confused at this point and have 2 theories.

Is it possible that the strut (Magnum AGV038MT- crossreferences to the OEN(31200416) that was in there) is wrong and getting a better brand will fix the alignment. The spring shoe on the strut is awfully close to the tire(10mm) too in my opinion.

Is it possible that the whole subframe is not exactly where it's supposed to be thats causing the whole misalignment? By my rough calculations we're talking about 1.4 cm laterally and 2.5 cm longitudinally on the passenger side.
That seems like an awful lot and the subframe bolts don't have that much adjustment, if you're even supposed to adjust anything there.
The rubber mounts on the subframe are old, but don't look like they can be off by that much.

Any light that anyone can shed on this would be helpful.

[Tannaton]

Probably not one thing - lots of little things.

Unlikely the strut...

Subframe bushes & Wishbone bushes are key to this, as would a damaged/bent subframe.

TBH 2 degrees in camber isn't a lot... filing the top mount will make little to no difference.

Passenger front outside edge always wears faster if you go round roundabouts hard...

[laundryman]

Good Practise dictates that struts are changed as a pair for obvious reasons. From bitter experience and history on this forum, pattern parts in the suspension area dont work well, as you have shown by your having to file out holes! As Tannaton says, its probably wishbone rubbers. Please dont buy pattern wishbones. Refer back to tales of woe on this forum when fitted.

[benben]

my apologies, I got called away for work.

I ordered a set of subframe mounts and a pair of (original) wishbones. I replaced all the engine mounts about a month ago which made a huge difference. The engine came up about 15mm after replacing the 2 main ones. and the passenger side was rubbing on the subframe.
It seems logical that all other rubbers are in the same condition.

I fully agree with replacing in pairs, I normally do, and intended to, but I ran into the tire wear before I got to the other side.

When I do the wishbones I will pull off both struts and compare them. If anything looks off I will replace both with Volvo parts.

2 degrees of camber seems like it's way too much, you clearly see it when you look along the wheels from the back. The top of the tire was over a cm out.
I filed out the top hole of the 2 holes in the lower end of the strut, the one that is intended for the camber adjustment.

As for the roundabouts, we have very few and the XC is the family car, mostly driven gently by my wife.

Thank you both, I'll report back after the new rubbers.

[oragex]

Subframe mounts ? Do you mean bushes ? These are expensive to replace and rarely would affect geometry. At the very least, be sure to order a good quality part as some used inexpensive parts and had to do them again 6 months later

As for the geometry, I found out the camber adjustment plays little role on this car, I don't expect it to cause tire wear

Wishbones certainly can cause poor alignment, also inner or outer tire rods if they have 'play'

For the new strut, try to measure the gap between the top of the tire and the fender, see if it's the same on both front sides. Not impossible an aftermarket strut to have an incorrect geometry, but this would be something rare. When doing the wishbones, may as well pull both front struts and put them side by side to see if the lower bolt holes are a the same place

[tonygreen1966]

Are you sure the spring is located in the top rubber mount correctly? When I remove the lower front wishbones I tend to compress the springs with spring compressor clamps, this lifts the hub up making removal and refitting of the wishbone easier. Anyway last time I done it (repairs for an MOT) when I released the spring compressors I didn’t pay enough attention to the spring seating back in it’s top mount and I didn’t realise it didn’t seat correctly. Took it straight away to the MOT station for it’s MOT and luckily they spotted it. Just a thought.

[Clan]

Are you running around with low tyre pressures ? what do you use ? That's a classic cause of outer edge wear ...Try ECO settings , caster is not adjustable it is built into the design of the struts and hubs ,