Front end vibration
 

I have been experiencing slight front end vibration at around 60mph. I have taken my wheels in to be balanced twice and have been told they are a-ok.
What should I look at next? What else would make my Carrera feel like a wheel is out of balance? Any fun weekend replacements or adjustment I should try?

Meka,
you might want to check your wheel bearings. They could be worn or they could be loose. Could be other suspension components. Start with the easy stuff. You might want to research (search button) on tightening the bearing. I'd be inclined to pull the wheel off, remove the end cap and check the washer behind the nut for tightness. Might be worth it to remove the bearings, clean, inspect for wear (replace if necessary) and repack with a good synthetic wheel bearing grease, tighten to the point that the washer is snug to move with a screw driver (side to side-top to bottom) and then lock it down. Do a test drive and see if that makes a difference.

Had the same thing - minor at first. Balanced wheels didn't help. Then noticed around 40mph that there was a pulse through the brake pedal if I braked very gently. Did front disks this weekend (and bearing re-pack/tighten as long as I had to open them up anyway) and solved the problem.

BTW - Pelican was down Saturday, and I had a H*ll of a time getting those dust caps off. On Sunday, searched and found a few threads on using a giant U-clamp to help pry them off. They are very strong (not tin-foil like) and usually very stuck) Do yourself a favor and search to save a big headache in getting those off.

meka, on my car it was 70mph. it was the ball joints.

An easy test: If it is wheel bearing looseness, you should be able to jack up the front and shake the wheel side to side and feel a little play, if I'm not mistaken.

Used to work on bicycles a bit in High School. Surprising how much of that feel of wheel bearings/races applies to cars (before cartridge bearings).

take a good long hard look at your tires as well, preferably off the car or jacked up. I had a similar problem and had them balanced perfectly to try to correct it. Did not work so we jacked up the front and then back end and spun the tires- broken belt/ flat spots in both front tires. Sometimes when people balance the wheels they do not even look at them.

+1 on the rubber. Being balanced does not necessarily mean the tires are in good shape. Even very minor discrepancies might cause those symptoms.

Right....the front end and steering of a 911 is very sensitive, and will transmit everything. Which is good. And bad.

Rotate front tires to rear. If it goes away, or gets worse, you know the tires are a contributing factor. It could be a flat spot on the treads, or an internal flat spot from sitting, or an internal belt issue. (I had that once, the vibes came and went as they canceled or magnified each other as the tires rotated differently thru the corners).

Next wheel bearings. With the car on the ground, grab the top of the front tires and push and pull to and from the center of the car. If you feel slop, it's very likely the bearings. Doing the same thing at 9 and 3 o'clock will often show slop in the steering linage, often the tie rods.

next jack it up and perform the same tests. Watch the lower ball joint for movement.

Odds are it's a tire.

How long the the car sit at any given time? My Bridgestones get flat spots if I don't drive it every couple of weeks. Once I get it out on the freeway and the tires get warmed up (about 20 minutes), the vibration goes away.

I had a similar issue with my 89 carrera and I went through all of the usual things, Balance, Bearings, Tie rod ends, steering rack, ball joints, all checked out fine yet I still had the problem. With alot of further investigation and time, it came down to the steering shaft u-joints. There was an extremely small amount of play (almost undetectable) in one of them and I couldn't tell if there was any play in the other. Anyway I replaced both of them and the the problem is completely gone. Good luck

Seems to me we read this complaint about once a week. In my 13 years of Porsche ownership this problem (which I have had several times) is always a tire balance question. Doesn't mean it can't be worn bearings or flat spots or bad tie rods or any number of other issues but the tires should always be, IMHO, the first issue to address. Now we come to the rub. Many wheel balancers and wheel balancing machines aren't good enough for your Porsche. Do yourself a favor and google the Hunter wheel balancing site. Read about their high end machine...which imposes a heavy load on the rotating wheel/tire thereby stimulating road conditions better than any other machine I know of. Enter your zip code in the box on their site to find a dealer near you who has this machine...there are only three in my town compared to the over 100 people who claim they balance tires. Then try it. It has worked for me. No interest or affiliation etc...