Highway speed vibration ('57 Thunderbird)

[yblock57]

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?

[dmsfrr]

Originally Posted by yblock57

. . . Run the exact same tire on the '57 Fairlane with no issues . . .
. . .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?

Have you tried swapping the T-Bird tires and wheels with the ones from the Fairlane? That will tell you if the shaking problem stays with the car or the tires/wheels.

The T-Bird steering wheel, steering column and steering box shaft all have keyed wide splines so they only fit together one way, and should be in the "straight-ahead" position.

Because the steering wheel is off-center something underneath needs attention and could be the source of the vibration.
Worn or dried out A-arm bushings aren't helping.

Might be time to find a good friendly front-end / alignment shop.
.

[Brian54]

I am experiencing the same issues with my 1954 Victoria ; hopefully, someone else has and found a solution to the problem . All feedback will be welcome .

[yblock57]

Originally Posted by dmsfrr

Have you tried swapping the T-Bird tires and wheels with the ones from the Fairlane? That will tell you if the shaking problem stays with the car or the tires/wheels.

IIRC the T-Bird steering wheel, steering column and steering box shaft each have keyed wide splines so they only fit together one way, and should be in the "straight-ahead" position.

Because the steering wheel is off-center something underneath needs attention and could be the source of the vibration.
Worn or dried out A-arm bushings aren't helping.

Might be time to find a good friendly front-end / alignment shop.
.

Took the words right outa my mouth. Will swap wheels with the fairlane and see if that changes anything.

Also will do some more poking around on the front end and see what else needs replacing. Anticipating a lot.

Wasn't aware of the keyed splines on the wheel/column/box. Could the off-center wheel be due to tie-rod ends being out of adjustment?

[CSPIDY]

I have the same issue on my 57 Tbird, same speeds, same tires, I have wire wheels and have isolated it to a bad wheel.
those BF Goodrich Silvertown tires seem to look like a snake when they rotate, not a big fan.

[dmsfrr]

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Originally Posted by yblock57

. . Could the off-center wheel be due to tie-rod ends being out of adjustment?

Yes, to re-center the steering wheel make one tie-rod slightly shorter and the other the same amount longer, while keeping the correct overall amount of toe-in. (approx 1/16 to 1/8 inch)
If the front end is shaking other repairs will be needed.
.

[wellcraft17]

Check the balance of your brake drums if they are original, they came from the factory unbalanced. Old school bubble balancer is the best way to check.

[dmsfrr]

Originally Posted by CSPIDY

I have the same issue on my 57 Tbird, same speeds, same tires, I have wire wheels and have isolated it to a bad wheel.
those BF Goodrich Silvertown tires seem to look like a snake when they rotate, not a big fan.

yblock57, here's a quick & dirty DIY way to ballpark check the wheels and tires for any wobble or out-of-round.

One at a time lift each one slightly off the ground in a well lit area. Place a bucket or similar item next to the wheel or tire with a length of wood or metal across the top. Place one end of it very close to an edge or tread surface of the wheel or tire and spin the tire/wheel fairly slowly by hand.
Look closely at the gap while spinning the tire/wheel and you'll be able to see any irregularity.

[ponymare]

It could be the bushing in the tail housing is worn also.

[yblock57]

I’ll definitely test the run out on the wheels.

I just replaced the tail shaft bushing due to excessive play/leaking fluid. Forgot to mention that.

Appreciate the help.

[Daves55Sedan]

Originally Posted by yblock57

I just replaced the tail shaft bushing due to excessive play/leaking fluid.

Do you know for sure that the driveshaft is original and/or has not been abused? It should have counterbalance weight(s) near the front. If not I would be suspect. How much of a gap is there between the front of the yoke and back of the rear extension housing. If the yoke is sticking out too far, and the driveshaft is out of balance, you will definitely have rear bushing wear and driveshaft wobbling.
If control arm bushings are really bad allowing movement between pin and control arm, those may cause alignment problems which could transmit to high speed vibration if front-end alignment is a little off.
Suggest looking at steering idler arm for excessive free-play too.

[yblock57]

Originally Posted by Daves55Sedan

Do you know for sure that the driveshaft is original and/or has not been abused? It should have counterbalance weight(s) near the front. If not I would be suspect. How much of a gap is there between the front of the yoke and back of the rear extension housing. If the yoke is sticking out too far, and the driveshaft is out of balance, you will definitely have rear bushing wear and driveshaft wobbling.
If control arm bushings are really bad allowing movement between pin and control arm, those may cause alignment problems which could transmit to high speed vibration if front-end alignment is a little off.
Suggest looking at steering idler arm for excessive free-play too.

Nothing's really for sure, but we had a reputable driveshaft shop check it out and install Spicer universal joints. If something had been out of wack, I would 'hope' it would've been caught then. Again, just going off what Dad told me.

The transmission was recently rebuilt and the rebuilder did not replace the output shaft bushing. Not sure if that's something they normally check anyway. We pulled it out for a bench job due to the excessive labor costs of pulling the engine to get the trans out. Only reason I noticed it, was the new seal leaking that upon further investigation showed some slack in the yoke. Bushing appeared to be original. Yoke surface is fine with no grooves. New bushing remedied the slack so at least that's one less thing on the list.

I have not measured yoke engagement, but will do when i get the car back up on stands. From what I recall it's in there pretty deep. Was checking a lot when the bushing was replaced feeling for slack. There are definitely no weights anywhere on the driveshaft.

[KULTULZ]

... those BF Goodrich Silvertown tires seem to look like a snake when they rotate, not a big fan

While you have it on stands, look for COUNTRY OF ORIGIN on the sidewalls.

If a man sectioned the AT out of a BIRD to rebuild it and did not replace the rear bushing as a matter-of-fact, it is hard to say what you will find.

[yblock57]

Originally Posted by KULTULZ

While you have it on stands, look for COUNTRY OF ORIGIN on the sidewalls.

If a man sectioned the AT out of a BIRD to rebuild it and did not replace the rear bushing as a matter-of-fact, it is hard to say what you will find.

Ha. Good point. The fordomatic debacle was a whole other can of worms covered in another very long thread. Hopefully that's behind me **knock on wood**

The Silvertowns where made by Coker using the old BF Goodrich molds. At least that's what we were told. Have the same tire on the '57 Fairlane 500 with no issues. Of course that doesn't really mean much, but we'll see.

[Dobie Gillis]

I've had no luck with Coker tires. I run Diamondback radials on the Merc. Unlike Coker, Diamondback does not make tires, they buy brand name tires from various manufacturers and apply their proprietary whitewall compound to them. Mine are actually Toyo.

[yblock57]

Originally Posted by Dobie Gillis

I've had no luck with Coker tires. I run Diamondback radials on the Merc. Unlike Coker, Diamondback does not make tires, they buy brand name tires from various manufacturers and apply their proprietary whitewall compound to them. Mine are actually Toyo.

I have heard good things about Diamondback. Went through 2 sets of 'Coker Classic' bias-plys and finally went with the Silvertowns as we had good luck with several sets in the past.

Call me stubborn, but I like the pie crust sidewalls on the bias-ply tires vs the more modern radials. Handling isn't a concern (obviously)! These cars only get out for weekend fair-weather cruising.

Will get the car out this weekend for some testing and get it back on stands and report back results.

[miker98038]

I currently have 2 sets of Diamond Backs, one BFG and one Nitto. Both are great, but getting old. I’ve also got a set of the Coker Bias look radials, 6.50 15 and 8.20 15’s and they balanced easily, and drive great. Way better than the previous bias ply’s. Both company’s are pretty proud of their products and your wallet feels it.

To the original topic, replacing the old A arm bushings is a pain, but it made a big difference in my 55 bird.

[KULTULZ]

Mine are actually Toyo.

The side walls on your tires are branded TOYO on a '53 MERC?

Have you no shame?

[Dobie Gillis]

Yup, they're Toyo made in White, GA. You'd only know they're Toyo if you crawled under the car and looked; the process of adding the whitewall obliterates the name.

[KULTULZ]

... well ...

I guess I can save the GIG if the name is hidden ...