ok, first off THANKS to everyone for the great ideas! 

I replaced the hub this weekend.  Got the lateral runout to .003, which is spectacular; better than the other side actually.  Also the weirdness when tightening the spindle nut is gone.

The fore/aft runout of the wheel studs was over .018, now about .005.  So i think this confirms that the hub was bad, and im assuming it shows the spindle is good.

However, the problem still isnt totally solved;  It is MUCH better though.  At first drive, it was probably 50% better.  I then switched the tires on that side from front to rear.  It is now 90% better than before.  My assumption is that the tire wasout fo round due to the pounding from a bad hub.

However, it still isnt gone.  And it still happens at 52 mph (indicated).  IM really at a loss as to what to look at next?  What else can i check?  Im out of ideas.

If there arent any other ideas, i may have to relent and take it to a pro.  Of course, as you all know, finding a really good suspension guy who works on old cars and doesnt just replace parts is REALLY hard to find!  Im assuming that they could check tire roundness, etc as well

Thanks again for all of the ideas/help!  I continue to be amazed by the experience, helpfulness, and knowledge here!

Ron Grove

Wauconda, IL

Try swapping the other front tire to the back. Maybe the vibration occured on both sides. Glad we could help as much as we did. Try, also, running it up to 60 or so and kick it in neutral, let it idle and be SURE the vibration is all from that tire as it slows through your 52 mph. 

Frank/Rebop

Bristol, In ( by Elkhart) 

one final thing to check closely is the idler arm,you said you replaced about 8 years ago and idler armsd are noted to wear prematurely,also have you tires roadforce balanced.it's a fairly new procedure to isolate a bad tire.out of round tires or tires with extreme heavy spots are very common and sometimes difficult to diag with just a balance.you can actually balance  a square tire and have it balance out but natually it is not going to run down on pavement.jim

Ron:

So moving the tires around changes the vibration?  Maybe you're on to something.  Simplyconnected gave us information on tire dynamics which was very enlightening.  Anyway, do you have a car with wheels that fit your car and do not vibrate?  If you have access to a set, put them on and try it.  Are you using repro wide whites or the newly available wide white radials?  I have read on other sites where there were problems with such tires, some are not made within our shores.  Tread wear is excessive on some of the offshore tires also.

John - "The Hoosier Hurricane"

Thanks again for all the additional ideas.  I completely forgot about road force balancing to figure out condition of tires and see if that helps.  I found a place in the next town over that has he newest Hunter machine and quoted me only $16/wheel to road force balance.  (most other places around here have charged up to $50/tire when ive had it done on other cars....)

I think that will be the next step, probably even before i keep moving tires around, etc.

As for the idler arm, etc. im still trying to figure that out.  If i put the car in the air, the pass side wheel wiggles the smallest bit if I do the tie rod wear test (hands at 9 & 3 and push/pull to check for wear).... BUT the movement is not in the tie rod ends... the whole linkage moves (again, just the tiniest bit), and i cant really see where the slop is.  The same test on the other side shows no wiggle/slop, so i need to spend some time on that too.  Again, the slop is miniscule, but its something.

One other thing; I can see the vibration at speed in the tip of the fender.  From the drivers seat looking at the tip of the stainless on top of the headlight bucket, I can see it oscillating up & down on the pass side but the drivers side is rock solid.  Thats whats making me think it is not likely to be a tie rod, but more like something out of round, etc.  Do you guys agree, or am i all wet?

Oh, and unfortunately I dont have another set of wheels/tires to try.  And the tires on there are Coker WW radials, about 5 years old.

Thanks again; Ill keep you posted once we get the road force balance done next week.

Ron Grove

Wauconda, IL

Ron:

I didn't mention any names earlier, and I don't endorse or condemn any dealers, but that brand is one that has been mentioned among the T-Bird club members as having balance and concentricity problems, and have problems getting them warrantied.  Sorry, Mr. Coker, I'm sure not all your tires cause problems, I only repeated what I've heard.  I have no personal experience with this company's tires.

Ron, what's your spare tire like?  Since you feel the problem is in the right front, put the spare there and try it.  Of course if you're chasinig more than one bad tire, switching only one tire at a time will only drive you crazy.

John - "The Hoosier Hurricane"

I'll second what John said about the Coker issue. They have/had a problem with eccentric tires. I don't run them so I'm repeating what I heard also. IF you discover that to be the problem I'd contact Coker (even 5 years later) and see if they'll replace the tire with this issue. I'd imagine they've had enough bad press on this issue that They'll want to avoid more hassles. They ought to be real cooperative. Particularly in light of what those tires cost.

Frank/Rebop

Bristol, In ( by Elkhart) 

yes, its funny; i was reading between the lines on the brands with "issues".  I have run into many people with issues with the cokers.  I didnt put too much thought into it because I had the same problem with the original bias plys that were on the car when we found it, then a set of Pirelli blackwalls (also not known to always be round, btw), and hten with the cokers.  But id be willing to bet that they arent helping the problem.  We had planned to get a new set of tires next year just due to age, and probably would not do cokers again due to stories of being out of round and also the WW kind of yellowing over time.  Probably do Diamond back classics this time around.....

As for the spare, it is a coker, and has a few k miles on it.  I rotated it out a while ago when I thought the issue was a bent rim; I used that rim as the spare, and havent given it another thought.  I have no idea if that rim is really bent, the tire is messed up, or if all is fine?

I may hold off on any other changes until i get the results from roadforce balancing.

Thanks!

Ron Grove

Wauconda, IL

I have cokers on my 56,i have replaced 4 of the 5 due to defects.two were tread separation and the other two was bubbles in the sidewalls.they balanced ok and have no vibration.probably had 8.000 miles when tread separated.coker prorated the tires and gave me a fairly good deal,but i doubt if i use them again.diamont t might be a better choice   Carl  Ohio

Wow, I thought Coker was better than that. Should be for the price. I guess it's par for the repro parts course.


Lawrenceville, GA