'05 XC70 shakes around 35-40- balance? Brakes?

[EamonnMR]

So I just recently got the suspension done and snow tires put on, because the old wagon was trying to shake itself to pieces on every bump. But in the clear light of fixed suspension, a new problem became visible-around 35 and 40mph I get wheel shake... Sometimes. The sometimes but is the most vexing part-if it was just wheel balance (and I took it to a tire shop to balance it-they 'fixed' it but the shakes came back) I'd expect it every time I hit a consistent speed.

My Father In Law did a diagnostic ride-along and found pretty convincing symptoms of a stuck rear brake-the car won't coast very far and very firmly stops when it coasts to a stop (in N) and when you feel the hubcaps after some driving, one of the rear ones is super hot (but not the others.) I was unable to reproduce the severe shakes at speed today for him though. Part of the problem is that roads out here are so garbage that you often can't tell if the wheels are shaking or if the surface is just... Always gonna be like that.

Anyone have any thoughts? I'm gonna deal with the stuck brake and see if that fixes it, but I'm kinda blank on what to check next, except maybe the wheel weights could have, like, fallen off I guess.

[vtl]

Check your parking brakes, old shoes can delaminate.

[oragex]

Good idea about the handbrake shoes, worth checking

For the intermittent steering shake, if it wasn't doing it before, I would still think at the tire balance or tire problem. Not all shops balance tires correctly - especially at the start of the winter season they hire newbies - got mines inflated to 45psi and shaking and rims scratched by one of these

Try also to see how much play you have in the CV joints - such play can cause slight vibrations that coupled with a slightly unbalanced tire, it may get into vibration resonance - a pretty strong vibration that comes and goes

Be careful with mechanics who say shocks can cause vibrations

[MoVolvos]

Friend's 83 240 Turbo use to have a steering vibration. It turned out to a slightly out of round rear tire. Back then there were no Road Hazard Warranties especially if tire balanced on a machine so he went to a specialty shop which shaved the tires and strobe balanced on the car.

[EamonnMR]

I should note that the vibration feels like it's on the vertical plane (my first thought was actually engine mounts), the steering isn't shaking particularly-the body if the car is (I mostly feel it in the seat!)

[volvolugnut]

Tires (especially old tires) can suddenly develop a defect like a bump on the side or tread. If not too large, this bump may cause resonance with the suspension at certain speeds. Did this occur both before and after snow tires?
volvolugnut

[oragex]

Was the drive shaft 'pulled' when the strut bolts were removed ? Was the hub hanging by the drive shaft without removing the axle center bolt ? That can affect the out CV joint. A 'vertical' steering shake can indicate a drive shaft problem. I'm not saying 'for sure', just a possible cause. Try to see if the vibration is related to the angle of the surface of the road - sometimes the left line is more inclined to the left, and the right line is inclined to the right. See if this is changing the vibration in any way. If yes, that would 'possibly' be related to a drive shaft

[E Showell]

Speed specific vibration is commonly caused by improper wheel balance. Throw a weight recently?

[abscate]

Deal with the brake first

Parking brake
Caliper stuck piston
Caliper pins

You can quickly check the caliper sticking problems by inspecting both sides of your rotors , they should look like mirrors, except for flash rust after a rain.

[EamonnMR]

Turns out it totally was a (now entirely roached) stuck caliper.