Front End Rattle

[zombielinux]

So in the quest to bring our '07 XC70 up to snuff, I'm making note of all the little noises and rattles the car has.

The chief among them is a nasty rattle and slight shake when running over a bump or small pothole in the road.

Its a largeish rattle thunking sound and slight shaking can be felt in the steering wheel.

I've already replaced the sway bar end links (they needed it) and part of the rattle went away. So it might be a composite of a number of different worn components.

From my research, it could be motor mounts, struts (and seats and whatnot), or tie rods. The car has 150K on it and few if any service records.

I had my better half try a test for motor mounts yesterday where she shifted from park to drive and to reverse while standing on the brake and I watched. There was some pitching but I'm not sure what would be considered excessive.

Any further suggestions?

[jonesg]

Tie rod end or control arm is what I'd inspect.
Also test the upper strut seats and ball joints.

Test tie rod by jacking up care, grab wheels and look for slop. Also look at ball joints when doing this.
Control arms I do visual check, looking for split boots.
Strut seats by turning the top nut a few degrees and see if it springs back to original position.(yes is good).

[zombielinux]

Well I had the control arm bushings replaced not long ago by a local volvo specialist and he mentioned the ball joints were in good shape.

I'll check out the others, but when I did the sway bar end links I yanked on what I thought were tie rods and felt no slop. I'll give the others a shot too and report back.

[jonesg]

Well I had the control arm bushings replaced not long ago by a local Volvo specialist and he mentioned the ball joints were in good shape.

I'll check out the others, but when I did the sway bar end links I yanked on what I thought were tie rods and felt no slop. I'll give the others a shot too and report back.

Testing tie rod requires the weight and leverage of the wheel to see it.
Grab top and bottom of tire , then try grabbing it at 3 and 9o'clock position.
It helps to have two people sometimes, one to yank the tire the other to watch for slight movement in joints.
Try levering things with a pry bar too.

[mrbrian200]

Question
What brand bushes did you have pressed into the LCAs?

I had trouble with some aftermarket bushes. Brand new the rear bushes didn't properly control LCA movement: The control arm was contacting the subframe over larger bumps/manhole covers etc. accompanied by a bit of what could be described as wheel shake and objectionable vehicle handling characteristics. Look for obvious contact between the LCA and the subframe. The upper/lower face LCA around the the outside of the bushing will show a somewhat flattened clean metal spots that are signs of obvious contact with the subframe that shouldn't be happening.

It would seem some bush suppliers are trying to address the issue of longevity by making the rubber on the rear bush more stretchy and/or adding material to the front bush giving it more resistance to normal suspension travel. Because of the particular geometry of these LCAs/front suspension this is exactly what you don't want to do.

[zombielinux]

I'll test the tie rods again today.

With respect to the control arm bushings, I'm not sure. I trusted the mechanic on this one. He's been there for 30+ years and appears to be the local Volvo specialist.

I'll do some more looking this afternoon.

[mrbrian200]

Noise from one side or both? If from both I'd almost bet $ it's the LCA bushes.

30 yr experience on Volvos means he's been working on P80s and older models forever. The LCAs on these older cars are a different design. Virtually any LCA bushes you get your hands on will work fine on those older Volvos with differences merely being NVH and longevity.

With regard to P2 and newer LCA bushes,

If you have or can get hold of a junk used tire (some tire shops will give tires that are too far gone to be resalable) cut this out from the sidewall and put it in the gap between the rear CA bush and the mount on the subframe as pictured. Note one side is open so you can stuff them in without taking the bolt out. Don't worry about the light peach colored material to test my theory you only need the tire rubber. If this is your problem the noise and wheel shake will become noticeably better (but not go completely away) as it's bouncing against medium hard rubber instead of metal to metal contact with the subframe. I chased around the whole front suspension and subframe bushes etc. pulling my hair out assuming because the LCA/bushes were brand new I was ruling them out as a potential problem. Nope. New LCA/bushes weren't suitable/bad even though they looked just fine. And they were a branded product from a long time Volvo OEM + aftermarket 'enthusiast' site your 30yr Volvo mechanic may well be ordering from. I have since come across a Volvo TSB regarding 'some aftermarket LCA bushes' though the TSB doesn't list specific brands.

[zombielinux]

Alright. Ill give my mechanic a call on monday and see what brand he put in there.

In the meantime, I had a chance to dive under the car and see what was up.

The transmission engine mount and the top engine mount are completely shot (like can move them freely around with my fingers shot).

I'm willing to bet that if these easy to access ones havn't been serviced, the harder ones havn't either.

I'm not seeing any contact between the control arms and the subframe (I've heard the rattle since this GA clay found its way into the car).

[JRL]

Don't forget the sway bar BUSHINGS can go bad

[zombielinux]

That is true. I should have checked those. IIRC they were a little cracked.