Where's the bounce coming from?

Dave0304XC · Post by **Dave0304XC** » 18 Oct 2022, 16:52

Hello! 2004 V70, 2.4. 106k miles currently. I bought the car back in February it was wearing 4 studded snows and had 4 loose 16" OEM alloys in the back. Painted the alloys and got 4 new Hankook tires.

After balancing the new tires it seemed to bounce, hop. Took wheels / tires to a more proper shop for a rebalance. They said if it still bounces it's probably because it has old original rear shocks.

Put 2 new Bilsteins in the rear. Still bounced, seems like 55 - 65 and under load is the worst. Then I Replaced both front struts, upper engine mount (worn and sloppy) and ball joints up on that big cross bar. Replaced right side engine mount (seemed ok) and that dog bone transmission to frame (worn and sloppy). Then had a full alignment done.

Drove it 1000 miles this weekend and it STILL BOUNCES. I think I notice it more from the passenger seat than the drivers side. Running out of ideas here. It does seem better and the ride seems smooth but I'm tired of the bounce. Maybe needs new control arms? Didn't change those, they probably are originals. Rolling along flat with the cruise at 70 it seems kinda smooth but not what Id call Ideal.

Do any Volvo veterans have any suggestions? Thank you!!! Dave

Post by **chrism** » 18 Oct 2022, 18:14

Shaking more under throttle load is indicative of a bad CV joint. If you say it’s worse on the passenger side then likely it’s the passenger side axle. If it does turn out to be the CV, you might consider having your OE axle rebuilt (not just re-greased and re-booted) vs an aftermarket unit.

Dave0304XC · Post by **Dave0304XC** » 18 Oct 2022, 19:36

Chrism- CV joint, I never thought of that. Sounds like a likely cause. It doesn't really make any noise, I always figured a worn cv would be noisy. Maybe I'll investigate getting a rebuild over the winter months, disable her in the spring. Dave

Post by **abscate** » 19 Oct 2022, 05:02

100k on original control arms/ ball joints is probably enough.

ignatz · Post by **ignatz** » 19 Oct 2022, 05:50

It be nice if someone close by with a spare set of Volvo wheels/tires could let you borrow them for 20 minutes.
I went through this bouncing problem with a used car purchase and my used set of wheels fixed the problem.
First I had the wheels balanced at the local tire shop. They said they were fine.
I then had two of my wheels/tires dismounted and one was shredding from the inside with pieces of tire inside the wheel.
The other tire had Calcium put inside.............yes Calcium from a Tractor shop.
All these wheels/tires were balanced and rebalanced at different shops.
My only saving grace while trying to fix the bouncing problem was that my used set of wheels made the car smooth as silk.
PS...as a car mechanic from the 70's...tapping on a 4oz wheel weight to the inside rear wheel was a fun prank to pull on another employee.

motormikeyman · Post by **motormikeyman** » 19 Oct 2022, 11:59

You didn't really say if it was doing this before you changed the tires or not. Assuming it was, I second the CV joints. I had the same vibration issue at speed under load. If felt like an alarming shimmy or pulsation in the floor and/or steering wheel. Changed both half shafts with Cardoni replacements and the problem is 95% gone. Should have used higher quality replacements!

Post by **Blacklab467** » 19 Oct 2022, 20:07

Probably the passenger side CV axle, they’re usually first to go. Get a good used GKN (OEM) axle from the wreckers, don’t buy aftermarket axles. Takes less than an hour to change.
In my experience with axles which has been extensive, the passenger side will usually go first causing a fairly low frequency vibration at 50 to 65 mph under acceleration. It gets worse with time quite fast, within a couple thousand miles, becoming almost undriveable.
Does it bounce…..like a suspension jounce or does it vibrate? That’s what we need to know.

Dave0304XC · Post by **Dave0304XC** » 20 Oct 2022, 06:56

Yeah I'd say it's a vibration. With new shocks in the rear and new struts in front, its a pretty firm ride. Are there places that rebuild oem axles? I might give a look. Dave

Post by **chrism** » 20 Oct 2022, 11:32

Dave0304XC wrote: ↑20 Oct 2022, 06:56 Yeah I'd say it's a vibration. With new shocks in the rear and new struts in front, its a pretty firm ride. Are there places that rebuild oem axles? I might give a look. Dave

I’ve had two or three axles reworked at Axles Unlimited in Charlotte NC and the results were good. It’s been quite a few years ago. At the time they offered lifetime warranty.

https://axlesunlimitedinc.com/

Dave0304XC · Post by **Dave0304XC** » 20 Oct 2022, 19:38

I watched a couple of youtubes on rebuilding cv joints, basically (according to these videos) it looks like a disassembly, clean out, grease up and new boot. Is that really all there is to a rebuild? No bearing replacement? Looks messy, but doable. Dave