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Very strange steering vibration issue?

 
  #16  
Old 04-11-2014, 04:21 AM
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Originally Posted by vince_1972 View Post
See if the centering ring of the wheel is not broken or improperly applied
Thanks for the tip Vince.

The wheels are OEM alloys and the centre ring is clean. The hub ring is new because of the new wheel bearings.

Tommorow I am getting tyres checked else where. If they are OK I will get some new rotors. I do brake hard and maybe one time I did not let them cool properly or for long enough.
 
  #17  
Old 04-11-2014, 04:34 AM
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Originally Posted by XWCGT View Post
No, actually there is radial run out. ("vertical run out") which is rarely ever seen unless the rotors are the wrong ones and are not centered properly, OR, there is axial run out, and this is where the rotors wobble horizontally. this is the MOST common. and, the pads wont wear down and have no effect just by the nature of the pads being able to be pushed back in the calipers when they are not being applied by the brake pedal. the pads will NEVER "clear" the runout because that's not how the braking system works. they are always left after brake application to just float over the surfaces and if there is contact, there is nothing to keep the pads in place but the fluid in the lines and calipers.

If you have a vibration, its the tires balance or its runout.
Not trying to argue, but I am 51 years old and have replaced brakes for over 30 years. I know exactly how brake systems work, and I have a jig and micrometer to test runout when I replace pads and/or rotors.

With that being said, I hope the original poster finds his issue. I know this must be an irritating thing.

Once the issue is resolved, come back and let us know.
 
  #18  
Old 04-11-2014, 04:57 AM
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Originally Posted by rscultho View Post
Not trying to argue, but I am 51 years old and have replaced brakes for over 30 years. I know exactly how brake systems work, and I have a jig and micrometer to test runout when I replace pads and/or rotors.

With that being said, I hope the original poster finds his issue. I know this must be an irritating thing.

Once the issue is resolved, come back and let us know.

Yes I will. Will be useful for other future owners to know.
 
  #19  
Old 04-11-2014, 01:03 PM
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Originally Posted by vince_1972 View Post
See if the centering ring of the wheel is not broken or improperly applied
pretty easy to check the wheel by putting something heavy close to a jacked up wheel and tire combo on the car, and spinning the wheel and tire. a make shift dial indicator, if you will. . you see more than a mm or two of movement and you might have a bent rim or a centering issue. tires have more runnout and thats normal, but too much and you get a vibration that balancing just cant get rid of.
 
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Old 04-12-2014, 10:48 AM
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I did the tyre run out test. Great idea. Carefully observed the solid object next to wheel when turned and they were completely straight and true. So no problem there.

I could order yet another set of tyres but I might see if I can borrow someone elses Vantage front wheels and see if that solves it. Or maybe buy some off ebay and sell them after or keep them for track days.
 

Last edited by Vergis; 04-12-2014 at 10:58 AM.
  #21  
Old 04-14-2014, 01:02 PM
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Originally Posted by rscultho View Post
Not trying to argue, but I am 51 years old and have replaced brakes for over 30 years. I know exactly how brake systems work, and I have a jig and micrometer to test runout when I replace pads and/or rotors.

With that being said, I hope the original poster finds his issue. I know this must be an irritating thing.

Once the issue is resolved, come back and let us know.

Yes, but you said: "The pads will wear until the material is clear of the excessive runout. However, with excessive runout there will also be pulsing in the brake pedal."

Im not trying to argue, just make sure the correct information is available. If you "know exactly" how brakes work, then you would know that what you said , cant happen. But you are right and we agree, the most likely issue is the tire balance. brakes have radial and axial runout, and radial is never seen unless the rotor is not centered. Axial runout is common for warping. Having designed/installed custom racing brake systems and raced the cars as well, this kind of problem usually cant be felt in a non braking operation, because the pads can be pushed back in as you drive.
 
  #22  
Old 04-18-2014, 12:36 PM
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OK taken a new direction in resolving this.

Swopped the front wheels with the rear wheels and the wobble still occurs but only at higher speed. So instead of happening at 55 mph it starts at 70 mph.

The rear wheel bearings have no play so that rules that out.

All 4 shocks are in good condition with no weeping.

Examining the bushes the rear torsion bar bushes are showing disintegration on the surface. The front right wishbone has a very fine split in the bush ! Since the car is approaching 9 years old it wouldnt be out of place for this to happen since they are probably Ford parts.

I have a hypothosis. The bushes maybe causing some oscillation in the wheels. Translating into wobble. Since the rear tyres/wheels are heavier that seems to have gone some way to dulling the wobble or oscillation due to worn bushes. The wobble only happened when I swopped the heavy front bridgestones for P-0 Nero, a lighter tyre. Before there was not any.

The bushes need to be replaced so I am booking the car in to have this done. May even upgrade to some decent poly bushes from the race cars if they fit. That should tighten up steering and improve cornering.
 

Last edited by Vergis; 04-18-2014 at 12:40 PM.
  #23  
Old 04-19-2014, 12:37 AM
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Originally Posted by Vergis View Post
OK taken a new direction in resolving this.

Swopped the front wheels with the rear wheels and the wobble still occurs but only at higher speed. So instead of happening at 55 mph it starts at 70 mph.

The rear wheel bearings have no play so that rules that out.

All 4 shocks are in good condition with no weeping.

Examining the bushes the rear torsion bar bushes are showing disintegration on the surface. The front right wishbone has a very fine split in the bush ! Since the car is approaching 9 years old it wouldnt be out of place for this to happen since they are probably Ford parts.

I have a hypothosis. The bushes maybe causing some oscillation in the wheels. Translating into wobble. Since the rear tyres/wheels are heavier that seems to have gone some way to dulling the wobble or oscillation due to worn bushes. The wobble only happened when I swopped the heavy front bridgestones for P-0 Nero, a lighter tyre. Before there was not any.

The bushes need to be replaced so I am booking the car in to have this done. May even upgrade to some decent poly bushes from the race cars if they fit. That should tighten up steering and improve cornering.
i dont think its bushings. the fact that you swapped wheels and tires with the rear, only moves the problem. it could be still there, but not noticable until a higher speed now... possibly due to the fact that if the problem is still there, but moved to the rear, those problems might not be felt until its a greater problem, which usually happens at a higher speed.
unless you have some type of problem with suspension, (something reallly loose, or brake calipers that are dragging, and then overheating and then warping the rotors ) i dont see the problem being anything other than balancing issues.
 
  #24  
Old 04-19-2014, 01:45 AM
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Originally Posted by XWCGT View Post
i dont think its bushings. the fact that you swapped wheels and tires with the rear, only moves the problem. it could be still there, but not noticable until a higher speed now... possibly due to the fact that if the problem is still there, but moved to the rear, those problems might not be felt until its a greater problem, which usually happens at a higher speed.
unless you have some type of problem with suspension, (something reallly loose, or brake calipers that are dragging, and then overheating and then warping the rotors ) i dont see the problem being anything other than balancing issues.
Yes potentially. However I have had 2 sets of new front tyres put on to rule out wheel balancing. Still the problem persists.

However you maybe correct. The problem could be moved to the rear. Im taking it to a specialist that have lots of wheels as well and will be able to test with another set on the front.
 
  #25  
Old 04-19-2014, 05:27 AM
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This is a long shot, but should checked anyway, the stering rack and bushings. May also be a bent axel, but sounds like bent rims. If it were me, i would try wheels/tires from another car that are perfect, and if wiling put your wheels on that car and test.
 
 
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