Daddio

951 has "floating" sensation as speed increases. Lower bushings, wheel bearings, etc. are firm and intact with no play. New tie rods and control arms, and good tires are fully inflated. Shocks are firm, and when the fenders are rocked by hand, the car immediately stops rocking when released.

Alignment seems good, checked by Smart strings method: Car tracks straight ahead "hands off" on smooth, level, straight highway.

However, the car "floats" at speed, giving the same sensation as if it were light in the front. I adjusted the front suspension by slightly increasing the toe in--it still tracks straight "hands off" but this toe adjustment made no difference in the floating sensation.

There appears to be slight play at the upper strut mounts, although all nuts are snug. If that's the source of the floating, would all of this come on in just a couple of hundred miles?

Your insight and suggestions appreciated!

J Chen

Are you using aftermarket shocks & springs
or standard shocks with uprated springs ?

Bret 944

Maybe a swaybar problem ? I had similar effects when one side of my swaybar jumped out of the outer bushing. Don't ask how.

Daddio

I'm using stock '86 951 springs and strut housings, but with aftermarket cartridges inside. Maybe they're toast, but the car feels fine when bouncing the fenders by hand. I'm about to install some new Koni strut cartridges from Paragon, and so have not gone through the whole expensive laser alignment process until that's done.

However, it's a mystery why this floating phenomenon would happen only in the past couple of hundred miles, having been rock solid til then.

Yesterday, put the car up on a rack and two mechanics and I poked and prodded everything for looseness, excessive play, firm bushings, etc.. The only thing we found was slight play (~1/16") at the upper strut mounts.

J Chen

How long have you use the aftermarket cartridges ?
I had a pair of gas shocks that was toasted with
only 2K miles on it in my Audi A4.

Daddio

The aftermarket cartridges have been in there awhile, so they're not all that new. OTOH, they haven't too many miles on them, either.

When I rock the car by hand, the shocks are firm, and the car immediately stops rocking when I let go. So, the shocks seem OK.

A big mystery is: Why would this floating sensation all happen in the last few hundred miles?

jimbo1111

Are you driving without the under body panels? When I took the panels off of my previous 951 to install a air splitter. I drove it without anything and the front end would lift at highway speeds. The whole front end felt very light.

Daddio

Yes, I have removed the under body panels--bat wing, and aluminum & black plastic lower engine covers.

I'd considered this, as seemingly air pressure would build beneath the nose, causing it to lift and float. OTOH, why would this phenomenon only present in the last few hundred miles? Last August, this car was in British Columbia 944 fest, and had no such problem even at twice the legal speed. And, the car does not seem to ride with a nose-high attitude. Weird, huh?

Peckster

Floating is not a very precise term. If your steering feels like the car is wandering, that might be worn control arms.

Rob 3

Is the front lifting or is the rear settling down? Is it a constant nose up attitude, or is it porpoising up and down at a slow rate? Has something settled in the back? The shocks dampen the spring oscillation, they wouldn't necessarily hold the front down so to speak. If for some reason the rear has gone soft on compression it might not resist any downforce you might have. If the inserts are gas pressure, they may be loosing the seal and thus the pressure of the shock. Has the stock ride height in static condition changed any? Is the floating speed related or more of a throttle/torque sensitive condition?

Daddio

Ride height and attitude are normal. Control arms & tie rods are new and firm. Tires new and properly inflated. Bushings & bearings firm and without play. Pinch clamps are tight, set at factory torque.

"Floating" is not particularly speed-related, though not too noticable til ~50+ mph. Car tracks straight (hands off) on a smooth & level highway at ~70 mph and all other legal speeds.

"Floating" refers to the steering having a slight lag--turn wheel a bit, and car takes a moment to respond. It sort of wallows, as if suspended on marshmallows, unlike the railroad tracks feeling it always had before.

There is a tiny (~1/16") bit of play in the upper strut bushings, about the same on both sides.

If the gas strut inserts are toast: 1.) why would both fail at the same time? and 2.) why is the front end firm when hand-rocking?

Bouncing the fenders by hand, the rocking stops immediately when the fender is released, so shocks are firm.

Charlotte944

I thought the same thing until I put Konis on my 951. The original shocks and struts were toast, but the car would not bounce when I pushed down on a fender.

The only real way to tell if the shocks are bad is to take them off.

Rob 3

If you are speaking of a phase delay from steering input to vehicle response, check rack mount location for any looseness as the issue may not be with the struts. You also mention new tires, are they the same as before or different brand. Different tires have different turn in response. Sounds like something is causing a delay from steering input to vehicle response which means something is causing a delay from input until the tires can generate enough lateral force to effect a change in direction, or something is changing your rate of weight transfer. Check the stay bar mounts to make sure everything there is tight, not only the link end, but where the bar mounts to the chassis. You might also want to check the link itself to make sure you don't have one that has sheared through such that the other one holds the bar when viewed statically, but under load, the sheared end isn't transferring any force until the bar flexes quite a bit.

tommye

Worn tires ???

Luis de Prat

Tire pressure too low?