Please help me solve this issue on my 68

[rolls 912]

Hi
Still haven't solved my steering wheel vibration issue. It oscillates left right and is at its worst at about 60 miles / 100 kms.

Wheels have been balanced 3 times and I'm told they are near perfect.

I have pulled apart the passenger side wheel bearings (which were replaced 3000kms ago) and have noticed wear marks on the bearing support ring - shiny faint groves. At least I know which wheel it's coming from now.

I've put in new bearings and the problem is worse.

Now I'm miffed. Any thoughts?

[gamin]

How old are the tires? I have had older tires even with good tread exhibit these symptoms at the end of useful life. Try increasing tire pressure a good amount. I did this with a shaking car and it smoothed out. If stock 68 all your tires are same size so rotate front to rear. May isolate the problem.

[Grady Clay]

rolls 912,

While this is almost certainly tires, it probably is compounded by ageing shocks, ball joints and tie rod ends. At 44 years, even the steering rack and other steering components can be suspect.

First, swap tires with a friend who has new-ish (round and balanced) tires & wheels.
It doesn’t matter the type or size so long as they are round and balanced. Up through 6x16 with 205/60-16 will fit. The 165/78-15 on 4½x15 ('64-'67 356C, 911 & 912) will work also.
A good trade for the test-use could be to have the wheels checked or re-balanced.

What is the measured run-out on your wheels (four measurements 2 radial & 2 lateral / wheel)?

What is the age and condition of the front suspension components?

Does anything feel loose when grabbing the tire (off the ground) and 'wiggling'?

Best,
Grady

[rolls 912]

Grady / Gamin

Everything is brand new - 5yr resto. Tyres are premium and new.

Also, when I pulled Apart the bearing the grease stunk! Hi temp, quality grease.

Hope this helps

[NoLift911]

15 inch Fuchs? What are your tire sizes?

[rolls 912]

Period correct 15 steelies.

205's

[NoLift911]

Sometimes 15's don't balance up nice. Couple things to try...I am sure it is still a balance issue if you have good run-out.

Try indexing the wheels on the hubs - rotate them 90 degrees and go for a spin see what that does. Mark the stud in relation to where the wheel is - you may need to do it a few times - the key is if it changes - then it is a balance issue. If so, you may need to have them match balanced on the car...this balances the whole assembly as there are three - the wheel, the tire and the rotor.

If your vibration moves in one direction or another (read speed wise changes from where the problem speed is) you have a balance issue.

You mentioned 3 times - same place? Did they calibrate the machine? Does the tech know what he is doing...just because a balancer comes up with 0 doesn't mean it is?

Do you have alot of balance weight on the wheels? Dynamic or static balance?

Do you have weight on one part of the wheel and then wheel weights exactly opposite on the same wheel?

Clip on or hammer on weights or tape weights?

Pics of the wheels and the weights and placement will help solve...

Let us know.

[rolls 912]

If your vibration moves in one direction or another (read speed wise changes from where the problem speed is) you have a balance issue.

You mentioned 3 times - same place? YesDid they calibrate the machine? Does the tech know what he is doing...just because a balancer comes up with 0 doesn't mean it is? These guys are very reputable. They prepare a lot of race cars.

Do you have alot of balance weight on the wheels? Dynamic or static balance? Dynamic only. Havent checked the weights. Hmmm, how does one static balance a wheel?

Do you have weight on one part of the wheel and then wheel weights exactly opposite on the same wheel?Will check

Clip on or hammer on weights or tape weights? (Hammer on the inside of the rim)

Tell me, how do i determine if the wheel is actually bent, apart from placing on a balancing machine?

Thanks for your detailed response

[NoLift911]

Originally Posted by rolls 912

If your vibration moves in one direction or another (read speed wise changes from where the problem speed is) you have a balance issue.

You mentioned 3 times - same place? YesDid they calibrate the machine? Does the tech know what he is doing...just because a balancer comes up with 0 doesn't mean it is? These guys are very reputable. They prepare a lot of race cars.

Do you have alot of balance weight on the wheels? Dynamic or static balance? Dynamic only. Havent checked the weights. Hmmm, how does one static balance a wheel?

Do you have weight on one part of the wheel and then wheel weights exactly opposite on the same wheel?Will check

Clip on or hammer on weights or tape weights? (Hammer on the inside of the rim)

Tell me, how do i determine if the wheel is actually bent, apart from placing on a balancing machine?

Thanks for your detailed response

If you only have weights on the inside of the wheels and not the outside - that is a static balance and might be your issue. For cosmetic reasons if you don't want weights on the outside of the rims you can place tape weights very close to the edge on the inside of the rim to achieve the same dynamic balance.

I doubt your wheel is bent - they would have noticed that on the balancer.

[docrodg]

While it is almost certainly the wheels you may want to check the brake rotors as they are part of the same rotating assembly and if they are out of balance could be same symptom. As I recall Porsche balanced the vented rotors.

[rolls 912]

Vented rotors are new from Zimms. Is there any way of checking?

I'll ask the boys to put weights on the outside then....

Thanks for the replies

[Peter Zimmermann]

I had a similar experience a few years ago. Put a set (four) of new Bridgestones on my SC. Mount & balance work was done by a well-known, very reputable shop (who is involved with racing); I have known the shop for more than twenty years. Drove home from the L.A. area to Bakersfield. Car shook so bad my arms were tired half way home.

Removed the front wheels at home, and took them to our local America's Tire (who I've used on three vehicles). They spun both wheels up, and found the balance on one to be off a bit, the other was way off. I took the wheels home, mounted them and went for a long drive. Car was perfect. Boy did I feel stupid for going all the way to L.A., to the "experts," and finally had to have the job completed three miles from home.

BTW; I didn't use the "experts" to have a set of tires put on my F 150, nor did I go to them for the set of tires that I put on my 914. America's Tire did both vehicles, and both are perfect - they even use torque wrenches and final tighten lug nuts by hand. Just because a tire shop does race cars, doesn't mean that the technician, or his machine, was ever used on a race car. Or calibrated.

My experience has been to never use the same alignment shop after an alignment problem, or use the same tire store after a balance problem. Unfortunately it's all a crap shoot, and I don't know too many people who can afford to put a wheel balancer, or an alignment rack, in their home garage.

[Trackrash]

Almost every time I have had new tires mounted on my 911 I have had vibration issues.

I have a BUBBLE BALANCER in my garage that I made myself. In every case the vibration went away after I re-balanced them with my home made bubble balancer.

It must have something to do with the way Fuchs mount on those spin balancers that tire shops use.

[rolls 912]

I've loaded new bearings. The wheel still vibrates.

I've since noticed that when the wheel is off the ground there is a slight wiggle. The bearings appear to be set correctly.

Any thoughts?

[pete3799]

Ball joint or tie rod end?

[warner53]

Turbo tie rods?

[Peter Zimmermann]

Back to post #12, this thread.

[rolls 912]

Thanks, gents.

Don't believe it would be the rim as the whole wheel wiggles, even with new bearings. Ive rechecked the packing - can just barely move the washer with a screwdriver so its nice and tight. Tell me, the bearing hub outer ring has been delicately tapped in? Is this right? They don't need to be pressed in do they?

Turbos, all joints etc are all new.

I'm thinking the spindles but I'm surprised that these would be worn...

Thanks again for the advice so far

[1QuickS]

The SWB cars preloaded the front wheels before setting toe to simulate the natural toe-out due to rolling friction of the tires. This was to help compensate for the rubber compliance in the front end. I think it was something like 35 pounds applied between the inner front rims. If there is that much compliance then the front end may be aligned correctly (statically) but experience toe-out under operational conditions. There would be a transition from toe-in to toe-out and the point of zero-toe could result in the vibration you experience.

I'd still look VERY closely at tire balance or distortion. You could jack the front end up and spin the tires to see how much mechanical out-of-round you may have. Premium tires shouldn't have much runout. If there is much mechanical runout then any amount of balancing won't fix the issue. There could also be a mechanical runout issue as a function of speed due to an imperfection within the carcass. Try swapping tires from front to rear to see if that helps or changes the speed at which the issue occurs or the magnitude of the issue.

[DRACO A5OG]

With the wheels off, grab the strut at bottom shaft and the dust shield, pull back and forth.

If there is slop, you found the culprit. If loose use a pipe wrench and tighten the heck out of the strut housing spanner nut.

If still loose, there is a cheap fix.

$.89 Fix! If not Loose Bearings, Tie Rods, Bushings, Joints or Strut Housing???

Jim