Front vibration through steering
 

So, several weeks ago I hit some debris on the highway on a rainy night (still shocked I didn't see whatever it is, but hey) that was significant enough to crack the bumper and take a chunk out of the left front wheel. So, as I was kinda looking for new wheels anyway, we wound up with a set of BBS RSIIs now. Next, we replaced the lower control arm and outer tie rod, since they had some play in them, and installed the full RoW M030 suspension. New Contisport 3's went on with the wheels.

Now, after all that, I STILL have a slight vibration that can only be felt through the steering that comes in between about 65-75 and then returns after about 85, varying in severity depending upon road speed.

Anybody have any insight as to what to look for next? This is driving me nuts! One would think the alignment rack would catch anything bent or out of spec, but the #s are perfect, so apparently not :(

Input much appreciated.

Patrick

Almost all vibrations are to be found in the wheels or tires. How were the tires mounted and balanced? Road Force balanced using a Hunter 97XX machine? Where were the tires purchased, locally or online? What did the Hunter machine print out about the tires being out-of-round (they ALL are to some degree, but must be within a certain tolerance in order to be balanced properly).

There could be other causes of what you're experiencing, but I'd be surprised in the answer doesn't lie in the tires/wheels.

I've battled wheel and body vibration in my boxster since I bought it. New tires fixed the problem twice, so I'd definitely agree with LB on this one.

If you did use a Hunter 9700 series machine to road force balance the wheels, I'd take it back and ask them to do it again and recheck their work.

Sometimes the weights should be put further toward the outside or inside of the rim to be in perfect balance, so ensure they are dynamically balancing them as well as road force balancing them.

Balance checks, and yes to the Hunter. What's concerning me is the possibility of damage to the hub/ bearing/ carrier assembly from hitting whatever it was that I hit. Short of swapping it all out and going for a drive to see if that cures the problem, anyone else have any ideas? I'd hate to replace all that if it didn't need to be. I suppose a bad bearing is a possibility as well.

Other than that, what else is there to blame?

Patrick

Next thing I'd check is a bent suspension member such as a Control Arm. These are alloy and would likely show some 'scars' after hitting some debris.

Already replaced the control arm and outer tie rod ends (both sides). I find it hard to believe, but I really am leaning to thinking there is damage to the hub/ hub carrier/ bearing.

Patrick

Yesterday I took the box down to discount tire to have them dynamically balance the wheels and use the Hunter 9700 road force process to insure the heaviest part of the wheel was matched with the lightest part of the tire to get the best fit.

This was done when I bought the wheels and tires, but not done since. My fronts were close enough to correct with weights. My rears, however, had moved 14 inches and had to be knocked off the rim and rotated around more than a foot so they'd line up again. Obviously, the weight of the motor and the force of hard acceleration and braking moved them a fraction of an inch many many times.

I still have some vibration up front though... so bearings are my next issue. I would imagine that your front end vibration is coming from a wheel bearing if you've had your front wheels dynamically balanced and road force balanced.

I doubt it's the wheel carrier itself. I've seen one torn down and everything bolts onto it nice and tight.

Sometimes you just get a bad tire that is slightly out of round or has a delam. internally that no one can see. That should get picked up on a careful wheel balance though.

Swapped a set of factory wheels with factory tires on the car today and went for a drive. Exact same problem. The issue is not with the wheel or the tire.

I think I'm going to replace the hub/ hub carrier as thats really what I'm suspecting to be the culprit here.

Patrick

OK, I can't even begin to describe the level of frustration I have with this problem. Replaced the entire hub/ hub carrier/ wheel bearing assembly today and the problem has not changed.

So, to recap, we have replaced

1) Front control arms
2) Inner and outer tie rods
3) Springs, dampers, strut tops
4) Sway bars
5) Replaced tires on my wheels (BBS RSIIs, which are about as true as a wheel gets), balanced them 3 times. Problem existed on old tires and new.
6) Tried a set of factory wheels, same exact problem.

The only thing things that have not been replaced or swapped out now are the front thrust arms and the actual steering rack. What gives???????

Patrick

Wheel Vibration
 

I have the same problem. I have vibration at 75 MPH plus. I'm going to get the wheels balanced and I'll let you know how it turns out.

Vibration Seems to be Gone
 

Had my wheels balanced this morning and went for a test drive. The vibration problem seems to be fixed, at least for now.

I've replaced everything up front now, with the exception of the steering rack. Given that I can feel a bit of "slop" just off center in the steering, I am unfortunately concluding this problem to lie within the rack itself.

Patrick

Does your car shake, or just the steering wheel?
I'm sorry hear about this snipe hunt of a problem you're having. Is there anyway it could be one of the rear wheels?

I find it odd that the steering rack would vibrate only at certain speeds. Then again, I'm hardly a mechanic.

Anyway, I hope that solves your problem.

Rears have been balanced as well. The rears are due for new meats, so I'm thinking I may replace those and double check all the alignment #s before ordering and swapping the rack out.

Patrick

Brake issue
 

Wondering if any one has had this issue with there boxster. yesterday i changed my rear pads and rotors with BHP pads and after market rotors and i'm haveing rubbing noise it seems like something is rubbing on one of the moving coponents. Has anyone ever had this issue buy the way my boxster is a 1998 boxster.
Thanks

My car had some vibration when it was time to replace there rears, noticeable at various speeds. Definitely a smart move to take care of that first. It fixed my shakes.

antthe4th, use the search feature to find the answer you're looking for.
Or click here: http://www.986forum.com/forums/search.php
I did a search for "brake rubbing" and found this:
http://www.986forum.com/forums/search.php?searchid=523701

Not sure this will help but I had a really bad vibration on the front right wheel and could not find the source. speed and slip angle were influencing the degree to which it could be felt. After a lot of searching, including the bearings we eventually found the front engine mount to be the culprit! replaced it and all vibrations were gone! In your case though my feeling goes towards the bearings...
Let us know when you pinpoint the cause!

The FRONT ENGINE MOUNT was the cause of your vibration felt through the STEERING? Now I'm really scratching my head!!

As stated, I have replaced the bearings, the hubs, the hub carriers- everything except the steering rack up front. Its going in for new rear meats, one more balance on all wheels, going back on the alignment rack, and we'll see if that fixes anything.

While its up on the lift, I'll have a look at the engine mount apparently.

Patrick

Actually, I think we can rule out the front engine mount. I just ran out to get groceries, and while driving I threw the car into neutral, with no change in vibration. I'll see have a look at it on the lift.

Patrick

Good for you! Yeah the vibration was mostly through the steering wheel and threw off everyone at the club that test drove the car while trying to help diagnose! Bearing was the most common suggestion... but wrong. I know how frustrating it is not to know what wrong and sympathize!

I had a similar problem a couple of months ago, driving in France. As soon as the speed picked up to around 75-80mph the steering wheel was visibly shaking. It disappeared after a 3 hour drive.

I think my problem was linked to the fact that the car is sitting around on the same contact patch on the tyre for days at a time and it had slightly deformed the tyre.

I think the long fast drive heated the tyre nicely and centrifugal force help to re-round it.

When you say you wound up with a set of BBS wheels that sounds like you did not buy them new. That makes me think it may be the front wheel may be bent. Also you can always get a shimmy from the steering wheel if you put enough air PSI in the front tires. Always spinup wheels on a tire balancer to see how out of balance they are before mounting a tire on them.

BBS wheels were purchased new, and they have been spun on a Hunter DSP and are about as true as wheels get. The problem was solved by using the Road Force balancer to re-mount the tires (all 4) to get the lowest road force. All are under 10 pounds now and things are perfect.

Patrick