I hit a couple potholes at high speed today and I continued driving pretty normally until I got on the highway and tried to accelerate. I got pretty strong shuddering and shaking from the wheels whenever I tried to accelerate past 50-60 MPH. It was pretty smooth when I wasn't on the gas pedal, but trying to gain speed resulted in shaking so bad I could hear creaking from all the plastic interior pieces. I don't think that's an engine problem since I had my spark plugs replaced by nice Bosch ones a month ago. It definitely feels like it's a suspension or alignment problem. I'm pretty sure that this car has all original suspension parts, so it could be that they decided to give in after a couple bad bumps. I read somewhere that on these cars, suspension parts are basically wear items. Is that true? I had my front tires replaced about 2 months ago and I didn't get them aligned, but it was fine because the car still drove very smoothly up to speeds of 90 MPH, the highest I've gone so far. I'm going to take it to a mechanic in the morning, but should it be safe to drive around conservatively in the city if needed? What parts could potentially be the problem and what would it take to fix it?

Thanks.

 

Considering you hit a pothole, the first thing to consider is wheel balance. Its possible you have bent a rim without losing air or knocked off a balancing weight. You should also inspect your tires for any sidewall damage (safety risk of a blow out). Vibrations that change with road speed point to any of the rotating components - ie tires, wheels, axles, hubs. You can rule out engine mounts if the vibrations go away when you let off the gas or shift into neutral at speed. If you hit something hard enough to bend a rim, your tech should also inspect for possible bent suspension parts as well such as control arms, struts - usually the fronts take the beating due to suspension angles.

 

So I went to my mechanic today and he took a look under the car and didn't see anything wrong there. Then we went on a little test drive and he didn't find anything because we weren't able to go very fast on the inside roads. He told me that if the shaking happens while accelerating around 60-65 MPH and goes away at 70 and higher and doesn't occur below 60, then it's the front struts. I went for a drive on the highway afterward and everything checked out. It was fine under 60, shuddering at 60-70, smooth after too. I came back to ask for an estimate, but he wasn't there at the moment. Before I go back, I just wanted to ask here if that makes any sense and how much it should cost with parts and labor to replace the front struts. Is it better to replace all struts at once, or just the ones that are bad and get the other ones when they go bad later? Are there any other parts that should be replaced along with the struts or anything? What are good brands of struts if not OEM? I know I saw Monroe on his shop walls and saw praise for the brand on another car forum in a thread for my exact car.

Thanks.

 

take a look at the struts yourself - do you see any signs of oil leaking from the piston? To the brand, should you decide to redo the struts a few things 1) Ask your mechanic if you can provide the parts and go and source Boge Sachs (OEM). 2) the Gen1 S40s are notorius for breaking springs (usually the last 2-3 inches of the flat part of the coil. You may want to consider replacing the springs when the struts are done. These cars are a pain doing the struts as the springs are very long and standard stick spring compressors don't work well - most shops have a better bench spring compressor so its good to let the shop do it for you. A quick look at FCP Euro prices the Struts at $81 each and Lesjofors springs at $63 (Genuine Volvo springs from Tascaparts.com go for $111, struts for $130) - I've already replaced 3 of 4 on my 2000 S40 and there are a number of posts reporting similarly broken springs (check it out). In the interim before you replace the struts, you can try a front/rear tire rotation to see if the vibration changes. If it does, then you know its the wheels.

 

That sounds to me like a bent/unbalanced wheel.

 

I just went to a tire shop to get my wheels balanced and the guy told me me my rear left tire had an imperfection, like a bump or something that caused the vibrations every time it turned. My right rear tire was also more worn than the left rear one, so I got new tires on the front and the front tires were moved to the back. Those were also new about a month or 2 ago and I had no problems with them.

The new tires and balancing did nothing. The shaking is still there, and I don’t know if my mind is playing tricks on me, but it seems to be a tad bit worse, but maybe that’s the roads I’m driving on today.

While the tires were off, I took a quick look at my struts and the general area. I found some grease or something coming out of something that looks like a miniature CV boot, but I don’t know what it is. I recorded the left side front wheel and found it.


If you skip to 0:18, you can see what I’m talking about. It looks flat and deflated. Could that be it? I couldn’t get better video cause I was recording blind, sorry.

 

 

I heard some 70s music in your video. LOL

That's an outer tie rod and they will show some grease at the seal since they have grease in them. The question is whether the tie rod end is loose where it bolts to the steering knuckle.

If the joint is worn out and loose at the connection you identified, it can cause a shake as the wheel wobbles back and forth. I've had bad ball joints also shake the front end. You should be able to ask your mechanic to check for both.

 

I have no idea what logic he is using to come up with that.