Need Input on Suspension Fix, High speed wobble won't go away Options

[Bristol]

Looking for a little input here on a '72 914. Front wheels wobble quite a bit, starting at 60 MPH. I've had the car for five years and it has always done this to some extent, but it has gotten a lot worse lately. Over the years I've tried a few things to fix it - had front wheels balanced, changed front shocks, installed turbo tie rods, front wheel bearings, bump steer kit for steering rack (car is lowered). It's not bump steer though, it is a strong back and forth wobble in the steering wheel that gets the worst at 60 mph. Recently I even changed the wheels/tires thinking that the tires were maybe too old or rims bent.

I finally got sick of this (because it's gotten worse) and took the car down for the final fix - new A-arm bushings, new ball joints, totally rebuilt the steering rack with new bearings, new grease, and a nylon coupler between the rack and steering shaft like Tangerine Racing makes with it shortened to account for the rack spacer kit. I also fully inspected the front for any cracks or broken welds.

Despite all of my efforts the steering wheel still shakes badly. I plan on putting the car back in the shop again to change the rear trailing arm bushings and I will remove the new wheels to have them road force balanced. I am hoping that the wheels (which came from another car) are just out of balance/round as this would be an obvious cause that I have not checked (balanced the old wheels, but not the new ones). I may just have bad luck and replaced old wheels with really old tires with new wheels in an unknown state of balance that also just happened to be out of balance...

Is there anything else that I am missing that I should check? The only things I can think of that I have not touched are the rubber upper shock mounts, but they "look" okay to me and the bearing/bushing directly behind the steering wheel.

Kirk

[GaroldShaffer]

what rims are you running?

[Mblizzard]

Two other things to check. While not likely to be the same in your car but my steering wheel bushing and bearings were quite worn and lose. A small vibration at 60 mph translated into a resonance frequency in the steering column and resulted in a big vibration at the steering wheel. During the course of replacing the bushings and bearings, I also noticed that the 4 bolts holding the steering column to the dash were not tight.

While there is still some vibration addressing these issues greatly reduced the problem.

[rick 918-S]

I can't tell from your photo in your avatar but one of two thoughts here. If you have a 5 lug conversion with wheel spacers that could be the issue. Incorrectly drilled rotors, uneven (untrue) spacers.

Or if still on 4 lug wheels you could have warped hubs from someone over torqueing the lugs with an impact gun. I always hand torque my wheels.

[Krieger]

I had a similar problem, maybe not as bad. It ended up being the my front wheel bearings were to loose.

[pcar916]

...It ended up being the my front wheel bearings were to loose.

(IMG:style_emoticons/default/agree.gif)

Tighten them up a wee bit and drive it... then do it again if it helped. Then inspect them a couple of times in the next year to be sure you're not cookin' 'em.

My theory is that the seats for the hub's bearing races get screwed up when folks use steel tools (like punches) to bang them out. When that happens the new races don't seat perfectly and take a few passes at the tightening sequence on the spindle-nut to get them seated.

Obviously the proper way to fix this problem is to true those seats.

Oh yes. Always use synthetic grease for wheel bearings... no downside.

Good luck

[luskesq]

I didn't catch if you have had the alignment checked, including camber & caster. If not and you indicate that you lowered the front end, it needs to be at the very least checked.

Keith

[Dave_Darling]

Swap the front wheels to the rear and see if that helps. (If you haven't done this six times already.) If no change, the problem is most likely not in the wheels or tires.

--DD

[andys]

Swap the front wheels to the rear and see if that helps. (If you haven't done this six times already.) If no change, the problem is most likely not in the wheels or tires.

--DD

+1

It's not uncommon to have a bent rim, defective tire (out of round), or simply improperly balanced. Swap will likely answer that question.

Andys

[Spoke]

I noticed with my 71 with 4 lugs that it was possible to mis-align the wheel on the hub since the hub has no centering ring. The wheel mis-centered on the hub would cause a great deal of wobble at higher speeds.

Therefore every time I removed the wheels I had to re-center the wheel on the hub by slightly loosening the lugs and nudge the wheel in one direction or the other.