Symptoms of bad LCAs?
 

Hey everyone,

So good news - my Boxster is finally enjoyable to drive again! After months of tracking down an infuriating vibration, I successfully remedied about 90% of the issue by installing new struts, mounts, track arms, trailing arms, and tie rods. I was able to do all the work myself thanks to the awesome knowledge from this board, so first of all, thank you to everyone who helped!

Secondly - as I mentioned, the issue is 90% gone, but there still is a bit of vibration and slight understeer noticeable. The only things I have not yet changed are front and rear LCAs, rear track arms, and rear drop links. Everything else in the front/rear suspension is new. I'm considering doing the front LCAs since they are relatively cheap (~90 each from Meyle) and shouldn't require an alignment. Could these potentially be the culprit from my last 10%? Before anyone asks, tires are brand new (Conti ExtremeContact DW) and alignment has been done.

Thanks again!

Have any of the wheel weights come off? Maybe have the tires re-balanced?

How are your wheel bearings ?

I'm skeptical that the LCAs are the cause of your vibration. I'd check what the previous posters mentioned, the wheels and wheel bearings. It is possible that the control arms are the cause of the vibration if they are completely shot, but I think you'd feel clunking and slop in the steering besides vibration. How many miles are on the car?

Why didn't you replace the LCAs when you replaced everything else? You will need an alignment after you replace the control arms, BTW.

I've had three different shops balance the tires, so I'm pretty certain this isn't the case. I had the vibration with my old tires and new tires.

I don't really notice any noise or play from them when spinning the wheels while up on jacks.

There is some slop in the steering as well - it's not as bad as before I did the other things, but still present. The car has 86k miles. I didn't do the LCAs because I figured I could do the fronts without needing an alignment - there are no eccentric bolts on the fronts.

Force balance tires.

Are the wheels true?
 

When the wheels were on the balancing machine did anyone test them to see if the actual rim was bent? I once found my wife's car with three bent rims (non Porsche but they were alloys). Spin at low speeds and hold a stick in a constant position relative to the edge of the rim and see if there is any variation. I was amazed there was no crack or other obvious deformity but they were definitely wobbling.

I had vibration as well at speeds of 70mph or above; however no slop in the steering. Had the wheels road force balanced and the vibration remained. Replaced all (4) LCA's and the vibration was gone. Apparently the bushings or ball joints had deteriorated enough to cause the vibration without any noticeable clunking. I then upgraded to the RoW M030 suspension and it felt like a brand new car.