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  1. #1

    Default Highway speed vibration ('57 Thunderbird)

    Getting a bad vibration starting around 55 mph that gets worse up to 65 then gets less intense at 70+, but still there. Very annoying. Feel it in the seat, steering wheel — whole car. Tires are 4 yr old B.F. Goodrich Silvertown bias-plys. Just had all 4 rebalanced. Rims are true. Tires didn't show any signs of trouble on the machine. Run the exact same tire on the '57 Fairlane with no issues, so doubting that's the trouble.

    Replaced:
    — shocks
    — universal joints
    — trans mount
    — engine steady rests

    Driveshaft does not have any weights. Would y'all have that checked next? Being so short I didn't think that would be an issue, but I want to get this thing cruising smooth. Car has not been on an alignment rack in over 40 years, but nothing has been changed/messed with in the front end. Could use A-arm bushings. Wheel is off center but doesn't pull. Very few miles put on it until recently.

    Thoughts?
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

  2. #2
    FEP Supporter Broncojunkie's Avatar
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    Definitely have it balanced by a good shop. Doesn't take much to throw them out. Even some sloppy undercoating or mud/dirt in the right spot can cause a vibration. The last one I had done (a few years ago) was by a local shop. They balanced it and upgraded the u-joints for around $100 and had it done the next day. They even cleaned it up and gave it a paint job. I good driveline shop is worth it's weight in gold (but hard to find, at least, where I live).
    79 Pace Car - 331, t5
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  3. #3

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    Quote Originally Posted by Broncojunkie View Post
    Definitely have it balanced by a good shop. Doesn't take much to throw them out. Even some sloppy undercoating or mud/dirt in the right spot can cause a vibration. The last one I had done (a few years ago) was by a local shop. They balanced it and upgraded the u-joints for around $100 and had it done the next day. They even cleaned it up and gave it a paint job. I good driveline shop is worth it's weight in gold (but hard to find, at least, where I live).
    Agreed! Dad had a good one do the universal joints and they were 'supposed' to have balanced. No weights, so maybe it was ok? It's a very short drive shaft on this car — about half the length of a fox.

    I'm going to do some more poking around. Will post up what I find.

    Thanks!
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

  4. #4
    Moderator wraithracing's Avatar
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    Does the vibration change at all if you put the car in neutral? Is the vibration constant at those speeds if accelerating or deccelerating?

    Was the vibration there before having the tires rebalanced or after? Were the tires rotated also?

    Has the car sat for long periods of time on the tires in the same spot? Did you drive the car for any distance or just immediately stop driving due to the vibration?

    I had a set of Kumho Ecsta tires on my old 98 Cobra. If that car sat for more than a week or two without being driven, it had the worst vibration I have ever felt while driving. Literally felt like the whole car was coming apart. Scared the H#ll out of me the first time. Vibration was worse as speeds increased. Checked everything. Finally figured out the tires would flat spot enough from sitting and then round back out after driving for about 10 minutes. Did it every time for the 3 years I had the tires on the car. Had a buddy with a 96 Impala SS with the same brand of tires and he had the same issues.
    ​Trey

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  5. #5

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    Quote Originally Posted by wraithracing View Post
    Does the vibration change at all if you put the car in neutral? Is the vibration constant at those speeds if accelerating or deccelerating?

    Was the vibration there before having the tires rebalanced or after? Were the tires rotated also?

    Has the car sat for long periods of time on the tires in the same spot? Did you drive the car for any distance or just immediately stop driving due to the vibration?

    I had a set of Kumho Ecsta tires on my old 98 Cobra. If that car sat for more than a week or two without being driven, it had the worst vibration I have ever felt while driving. Literally felt like the whole car was coming apart. Scared the H#ll out of me the first time. Vibration was worse as speeds increased. Checked everything. Finally figured out the tires would flat spot enough from sitting and then round back out after driving for about 10 minutes. Did it every time for the 3 years I had the tires on the car. Had a buddy with a 96 Impala SS with the same brand of tires and he had the same issues.
    Trey —

    The car has been doing this ever since it was awakened from its 20-year slumber. Don't have a good comparison as tires were purchased when we got it running. Old ones were too dry-rotted to trust at all on the road. Current tires appear to be good with no flat spots. Dad did say it used to cruise on the highway just fine.

    They were just rotated front to back and re-balanced at Discount Tire a couple weeks ago. They said they looked fine and didn't 'wander'.

    I have not tested out of gear at speed yet. Will try that along with running in a lower gear at same RPM this was happening to eliminate the driveline.

    Thanks!

  6. #6

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    Block the front tires and put jackstands under the rear axle tubes. "Drive" the car like this in different gears and at different speeds. This makes it very easy to determine if the vibration is engine or driveline speed related. Remove the rear wheels/tires and retest with five nuts holding the drums on. This will eliminate the rear tires and wheels as a source.
    Jack Hidley
    Maximum Motorsports Tech Support

  7. #7
    FEP Power Member fgross2006's Avatar
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    Quote Originally Posted by graphicdesigner80 View Post
    Getting a bad vibration starting around 55 mph that gets worse up to 65 then gets less intense at 70+, but still there. Very annoying. Feel it in the seat, steering wheel — whole car. Tires are 4 yr old B.F. Goodrich Silvertown bias-plys. Just had all 4 rebalanced. Rims are true. Tires didn't show any signs of trouble on the machine. Run the exact same tire on the '57 Fairlane with no issues, so doubting that's the trouble.

    Replaced:
    — shocks
    — universal joints
    — trans mount
    — engine steady rests

    Driveshaft does not have any weights. Would y'all have that checked next? Being so short I didn't think that would be an issue, but I want to get this thing cruising smooth. Car has not been on an alignment rack in over 40 years, but nothing has been changed/messed with in the front end. Could use A-arm bushings. Wheel is off center but doesn't pull. Very few miles put on it until recently.

    Thoughts?
    since its a 57, does it have front drum brakes? I had this kind of issue with a 67 Camaro way back. It turned out that the drums were counter balancing the tires. I went to a truck/specialty shop that had a machine for on the car wheel balance. It was $35 per tire back in 88. Only the fronts needed it at the time.

  8. #8

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    Quote Originally Posted by Jack Hidley View Post
    Block the front tires and put jackstands under the rear axle tubes. "Drive" the car like this in different gears and at different speeds. This makes it very easy to determine if the vibration is engine or driveline speed related. Remove the rear wheels/tires and retest with five nuts holding the drums on. This will eliminate the rear tires and wheels as a source.
    Thanks, Jack. That's on the list of things to try. Appreciate it!

  9. #9

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    Quote Originally Posted by fgross2006 View Post
    since its a 57, does it have front drum brakes? I had this kind of issue with a 67 Camaro way back. It turned out that the drums were counter balancing the tires. I went to a truck/specialty shop that had a machine for on the car wheel balance. It was $35 per tire back in 88. Only the fronts needed it at the time.
    Correct, car has drum brakes all the way around. I can't find anyone locally with that 'on the car' balancer, but have been eyeing a few ads for those contraptions a while. Shipping is very cost prohibitive though! Really the best way to balance as it accounts for the hub & drum as well.

    Have some troubleshooting to do. Will post back results. Thanks!

  10. #10
    FEP Power Member fgross2006's Avatar
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    Quote Originally Posted by graphicdesigner80 View Post
    Correct, car has drum brakes all the way around. I can't find anyone locally with that 'on the car' balancer, but have been eyeing a few ads for those contraptions a while. Shipping is very cost prohibitive though! Really the best way to balance as it accounts for the hub & drum as well.

    Have some troubleshooting to do. Will post back results. Thanks!
    I recall my 67 Camaro literally thumped up and down at 55 mph and higher. The steering wheel and dash were shaking like I was blasting off from Cape Canaveral. I would bet its the drums causing you this. The only place near me that had the machine to balance tires on car was a truck and spring shop. Try looking into a heavy duty shop, old school.

    Another thing to remember, if you do balance on the car, any time you need to remove a tire for any reason you have to mark a lug and a hole to put it back the same way or you throw it out of balance again.

  11. #11

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    Quote Originally Posted by fgross2006 View Post
    I recall my 67 Camaro literally thumped up and down at 55 mph and higher. The steering wheel and dash were shaking like I was blasting off from Cape Canaveral. I would bet its the drums causing you this. The only place near me that had the machine to balance tires on car was a truck and spring shop. Try looking into a heavy duty shop, old school.

    Another thing to remember, if you do balance on the car, any time you need to remove a tire for any reason you have to mark a lug and a hole to put it back the same way or you throw it out of balance again.
    You described exactly what's going on. If drums end up needing balancing, I guess said heavy truck shop should be able to do as well? Do you recall having to do them or were they taken care of when they balanced everything on the car?

    Exactly right on marking lug/rim orientation for later. Good stuff!

  12. #12
    FEP Power Member fgross2006's Avatar
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    Quote Originally Posted by graphicdesigner80 View Post
    You described exactly what's going on. If drums end up needing balancing, I guess said heavy truck shop should be able to do as well? Do you recall having to do them or were they taken care of when they balanced everything on the car?

    Exactly right on marking lug/rim orientation for later. Good stuff!
    They dont balance the drums as I recall. They spin the tire while its mounted and place the balancing weight accordingly, and that effectively balances the tire and drum together. They did my 2 front tires on the car. The rear the usual way. Its the fronts that need it.

  13. #13

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    I ran the car on stands up to 70 and didn’t feel what I feel on the road. Minimal vibration from the drivetrain spinning up that fast. I guess that rules out driveshaft, mounts, etc.

    What I do see are very wobbly rear tires and questionable rims. Hard to determine if both are at fault. YouTube video below. FYI they’re turning at about 15 mph… can only imagine what they look like at 70!

    https://youtu.be/E2q_aya7AkI

    Thoughts?
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

  14. #14

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    That doesn't look very good. You can measure the lateral runout of the wheel flange and the wheel mounting surface of the drum with a dial indicator. Those measurements will really mean something as there are established tolerances for both of them. Looking at run out on the drum, which isn't at the wheel mounting surface on it, doesn't really tell you anything.

    I would also pull the drum off the axle and measure the axle flange by itself. If it has any runout it will make everything bolted to it have runout also.

    Try putting these tires and wheels on the front, then spin them and watch them. Do they look like they have as much lateral runout?

    If the tires and wheels are just crappy, you can take them to a shop with a tire force balancer. They will rotate the tire on the rim at different phases to find the optimal phasing where the amount of total force runout is minimum.
    Jack Hidley
    Maximum Motorsports Tech Support

  15. #15

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    Quote Originally Posted by Jack Hidley View Post
    That doesn't look very good. You can measure the lateral runout of the wheel flange and the wheel mounting surface of the drum with a dial indicator. Those measurements will really mean something as there are established tolerances for both of them. Looking at run out on the drum, which isn't at the wheel mounting surface on it, doesn't really tell you anything.

    I would also pull the drum off the axle and measure the axle flange by itself. If it has any runout it will make everything bolted to it have runout also.

    Try putting these tires and wheels on the front, then spin them and watch them. Do they look like they have as much lateral runout?

    If the tires and wheels are just crappy, you can take them to a shop with a tire force balancer. They will rotate the tire on the rim at different phases to find the optimal phasing where the amount of total force runout is minimum.
    Thanks, Jack. Those are great ideas. I'll do some more testing and report back. Appreciate the help.

  16. #16

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    Eye-yi-yi … so much for wheels/tires. Upon checking for axle run out, a heck of a noise/vibration started. Does not do this in park. Only in reverse/drive. Double checked U-bolts. Can feel a small amount of slack in the yoke going into tail shaft of transmission. I have just replaced the bushing inside the tail shaft. Looks like it’s already leaking after putting a couple hundred miles on it. Doesn’t make sense that it would make that much noise and vibration at approx 15 mph in the video. Sounds/feels like it’s coming from inside the trans. What the heck?!?

    Thoughts?

    https://youtu.be/UMRg6J2dwVo
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

  17. #17
    FEP Super Member erratic50's Avatar
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    Bad skip yoke can cause bushings to fail very quickly

    get a new yoke

    balance the shaft

    have the transmission checked out

    If the bushing is installed wrong it won’t get lubricated. It will fail almost immediately and take the seal and yoke with it

  18. #18

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    Quote Originally Posted by erratic50 View Post
    Bad skip yoke can cause bushings to fail very quickly

    get a new yoke

    balance the shaft

    have the transmission checked out

    If the bushing is installed wrong it won’t get lubricated. It will fail almost immediately and take the seal and yoke with it
    Upon further research it looks like the wrong bushing was installed. New one didn’t have the oil grooves and is likely what’s causing all the issues. Correct one located and ordered. Slip yoke should be here tomorrow and it’s going back to the shop to get new universal joints and balanced. Will update when it’s back together.

    Thanks
    '84.5 GT vert / roller 5 liter 4v / t5
    '86 LX coupe / 331 / t5
    '86 F-150 - 5 liter / efi / aod
    '56 F-100 - 272 y-block / 3 on the tree

  19. #19

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    This thing is finally fixed. Turned out to the a combination of things. Firstly the wrong slip yoke was in the car. Discovered this by accident and bought the correct one (over 2" longer than what came out). Suspect the wrong one was for a standard 3-speed trans car and the Fordomatic this car has calls for a much longer one that will allow the new output bushing to live a longer life. Installed the right one and all's well on that front. That solved the ratta-tap-tap problem. Also went ahead and replaced the universal joints and had the drive shaft balanced to be totally sure. Also took the drums to the local parts store and ran them on the lathe. No visible runout observed. I'll call them good.

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    The second was tires. They had excessive radial runout. Sent back to Coker for warranty replacement. In the meantime Discount Tire gave us some standard radials to run. Dad's happy with how they ride, got the car up to 80 mph and everything's smooth and tracking fine. I don't like the look of the narrow white wall, but at this point its 'function over form'... heh.

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    Thanks to everyone who chimed in and helped! Now onto the next thing
    Last edited by graphicdesigner80; 10-27-2021 at 12:41 PM.

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