2005 xc90 2.5T drives like a bounce house

Post by **ZionXIX** » 02 Mar 2024, 06:30

I have the 2005 xc90 2.5T FWD with nivomats in the rear. When going over a bump in the highway or a sudden drop, the rear feel like it's floating seperate from the wheels. Tons of rear end sway, "the boat effect" I suppose. I want to see about replacing what's needed but when I take a pry bar to all the rear end bushings they seem pretty tight. The shocks are not leaking, the vehicle is not sagging in the rear. I'm considering just refreshing the entire rear suspension. However the P2 seems to have the most convoluted rear suspension I've ever seen. When I check FCP I'm not seeing all the bushings that are under there. Any thoughts on improve the rear stability?

chitownV · Post by **chitownV** » 03 Mar 2024, 13:25

Have you first replaced the rear trailing arm bushings? These wear out which can affect rear alignment and is a good first step. Volvo updated these to solid bushings.
https://www.swedespeed.com/threads/rear ... nt.519265/

The XC90 is top-heavy and the suspension improvements are first done with the front since that's 80-90% of the issues. Alignment can also help. Please read this thread for more info,
https://www.swedespeed.com/threads/chit ... ts.590829/

nedc · Post by **nedc** » 05 Mar 2024, 15:51

I also have a 2005 xc90 2.5t fwd and after doing some front end suspension work (control arms, struts, etc.) it still had a 'nervous' kind of jittery feel to me. If you put 2-300 lbs. in the rear hatch area, it actually rode better. What I did was replace the nivomats with 'regular' shocks- and you don't need to change the springs contrary to what I had read. I had the springs for the regular shocks but they were exactly like the nivo springs, so I left the nivo springs in. Rides much better and more controlled. We very rarely carry rear passengers or heavy loads, so I don't miss the nivomats.

Post by **ZionXIX** » 06 Mar 2024, 20:51

I replace the front control arms, lower ball joints and sway bar end links with OEM 2 years ago. I haven't touched the rear suspension. I wanted options first. I'm not opposed to replacing the struts and mounts. I've been researching the nivomat delete as well. Nivomat conversion looks to be the least amount of work as it does not require complete rear suspension disassembly. How ever the trailing arm bushings look like an intense job.

chitownV · Post by **chitownV** » 06 Mar 2024, 21:47

Even if you change the rear shocks, not changing worn out trailing arm bushings, the largest suspension bushings in the rear, will lead to dynamic alignment changes. Those bushings contribute to a delayed rear feeling on turns. It’s as necessary for the rear as control arm bushings are for the front.

If it seems like a big job to you, then have a shop do it. Or DIY it with a free bushing/ball joint tool rental from your local auto parts store.

Worn out bushings like these will contribute to more tire wear. Again, the alignment will get thrown off while driving.

Post by **ZionXIX** » 07 Mar 2024, 05:28

Ok, I just ordered some new trailing arm bushings. Those will get replaced first and then we will see how the ride changes.

Post by **ZionXIX** » 11 Mar 2024, 15:41

I do believe you guys are right about the trailing arm bushings. I just recieved the solid ones today. Will install sometime soon.

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chitownV · Post by **chitownV** » 11 Mar 2024, 17:18

Nice pics. That looks worn out and tearing.

Just don't ignore the front control arm bushings. If you used Lemforder, they are known to have soft rubber nowadays. It's not just Volvo as car owners from all the German car companies are complaining too. People are also complaining about new Volvo rubber bushings. I have them on my rearward control arm bushings and they are already worn out, causing hard braking pull, intermittent wheel vibration, and a clunk going over some bumps. I'll replace those with poly.

You can change the front struts without changing the rear Nivomats. That's how I have mine using Bilstein B4 Touring struts. Works very well and I've installed them in a 2006 2.5t with 3rd row and Nivomats with great results. Helps reduce the front tuck and nose dive on turns so the rear doesn't raise up. Doesn't bring harshness as the ride is more controlled with compliance. Unlike worn-out struts which have more oscillations, more nose dive, more weight transfer rear to front, and harsher on bumps due to reduced damping.

Post by **ZionXIX** » 11 Mar 2024, 22:03

chitownV wrote: ↑11 Mar 2024, 17:18 Nice pics. That looks worn out and tearing.

Just don't ignore the front control arm bushings. If you used Lemforder, they are known to have soft rubber nowadays. It's not just Volvo as car owners from all the German car companies are complaining too. People are also complaining about new Volvo rubber bushings. I have them on my rearward control arm bushings and they are already worn out, causing hard braking pull, intermittent wheel vibration, and a clunk going over some bumps. I'll replace those with poly.

You can change the front struts without changing the rear Nivomats. That's how I have mine using Bilstein B4 Touring struts. Works very well and I've installed them in a 2006 2.5t with 3rd row and Nivomats with great results. Helps reduce the front tuck and nose dive on turns so the rear doesn't raise up. Doesn't bring harshness as the ride is more controlled with compliance. Unlike worn-out struts which have more oscillations, more nose dive, more weight transfer rear to front, and harsher on bumps due to reduced damping.

I changed the front control arms 2 years ago. Maybe 6000 miles on them. If I change the front struts I thought about just converting the Nivomats to standard shocks.

chitownV · Post by **chitownV** » 12 Mar 2024, 01:46

ZionXIX wrote: ↑11 Mar 2024, 22:03
chitownV wrote: ↑11 Mar 2024, 17:18 Nice pics. That looks worn out and tearing.

Just don't ignore the front control arm bushings. If you used Lemforder, they are known to have soft rubber nowadays. It's not just Volvo as car owners from all the German car companies are complaining too. People are also complaining about new Volvo rubber bushings. I have them on my rearward control arm bushings and they are already worn out, causing hard braking pull, intermittent wheel vibration, and a clunk going over some bumps. I'll replace those with poly.

You can change the front struts without changing the rear Nivomats. That's how I have mine using Bilstein B4 Touring struts. Works very well and I've installed them in a 2006 2.5t with 3rd row and Nivomats with great results. Helps reduce the front tuck and nose dive on turns so the rear doesn't raise up. Doesn't bring harshness as the ride is more controlled with compliance. Unlike worn-out struts which have more oscillations, more nose dive, more weight transfer rear to front, and harsher on bumps due to reduced damping.
I changed the front control arms 2 years ago. Maybe 6000 miles on them. If I change the front struts I thought about just converting the Nivomats to standard shocks.

What brand control arms did you use as that is very very important?

Saying it was done doesn’t mean they are working properly. You said your XC90 is handling like a boat and 80%-90% of that has to do with the front suspension, even with how the rear responds.

Bushing flex, even with new rubber ones
What you are missing is that for years XC90 owners who even have brand new rubber control arm bushings still have issues with too much bushing flex. The soft bushings can cause the wandering/floatiness, vague on-center feel on the highway, make it more difficult to drive when windy, cause brake pull, delayed steering, and even tire feathering wearing out tires faster. There are more issues arising from the control arm bushings.

The rearward bushings flex too, yet it’s difficult to have a test. They can also contribute to brake pull, intermittent wheel vibration, and a knock/click on bumps.

Bushing Test
Here’s a free test I usually recommend to XC90 owners:
Get an old coolant hose and cut it up into 4-6in strips. Stuff these into the forward control arm bushings’ cutouts/voids. If your “boat” feeling improves while driving, then you know you have too soft bushings. The flex in these bushings are the #1 issue in the suspension and steering.

I’ve helped dozens and dozens of XC90 owners with their suspension setups and getting what fits their needs.

Struts and Shocks
BTW, the front struts and rear shocks don’t have to be done at the same time. If you have original front struts, then it is guaranteed worn out by now. Those struts and its hardware should be prioritized before the rear shocks. Do the front struts and then reassess.