Hot Rods (Not so) Good Vibrations... help!!

Hey all
I’ve been chasing around a vibration in my 53 Chevy and it’s driving me nuts. When I get to about 60mph I get a vibration. They say that at this speed the vibration would be due to wheels being wonky. Had them all balanced, vibration still exists. Noticed a buckle in the rim. Bought some brand new rear rims. Vibration still exists. Even with ew diff gears, new rear tailshaft universal joint and balanced tailshaft the vibration still exists...(though they were done for other reasons. It’s becoming a time consuming and costly venture. Help!

Now, when I’m accelerating the vibration is noticeable (blurry revision mirrors etc), but if I press the clutch in at speed, or back off the throttle the vibration is about twice as bad. The things I haven’t replaced are the front wheels and the tailshaft yoke. I figure I could replace the entire vehicle and that might solve it, but it might not. Help!


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Leaf bushings in the shackles?

 

I knew I left something out, those are fresh also! As are the leaves (problem was there with the old leaves too)


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Sound like you have converted to open drive … how's the pinion angle ? It should be same as back of trans. A needle dropped into a u-joint cap will do it, and check for loose pinion nut.

 

I hope you figure it out. I'm dying to know what it is.

 

I would look into having the drive shaft balanced. Or at least put an indicator on and see if it's has a bunch of runout. Maybe reposition driveshaft 90° on the yolk.

 

Yep, angles are the same. Mind you I had a different diff in it before and the problem was there also. Literally the only thing remaining is the yoke... but I would have hoped the driveshaft shop would have picked up on that when they shortened and balanced it


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True, I was thinking of that - rotating the tailshaft 90 on the yoke and 180 on the diff. Hmm don’t cost nothing but time


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Check for play in the output shaft bushing.

What transmission, and is there a crossmember under it?

 

True that. It’s a Camaro V8 T5 from 1989. Pretty fresh by all accounts, still, could be a thing


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And yep, there’s an aftermarket bolt in crossmember


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I would do it tomorrow morning after coffee and a small Cuban cigar. Perhaps a Bolivar Petite Corona... lol

 

Holy heck how do you know my morning routine?


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Well I found one interesting development. I put in a new set of stiffer, wider springs in the car. I paid a highly skilled professional to locate everything and throw it together. Turns out that the axle is sitting further forward now. So far in fact, that the yoke is almost bottoming out on the back of the gear box. Fak. So far forward, that you can’t even remove the freaking tailshaft anymore. Even with he axle hanging down there’s not enough extension to slip the rear uni out from the yoke. What a nightmare


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Could you re-drill the spring pads to move the axle back a bit ?

 

Could do. Bit of messing about, and I don’t think that’s the issue, as the vibration was there before relocating the diff on the new springs


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I had a car once that I could never figure out why it pulled to the right. I tried everything short of a new frame. After 14 years I sold it. I did learn how suspensions work and can do my own alignments now. But I wish I would of sold it after a year. My attitude today is either there right or wrong. The 69 el Camino I have now is a dream.

I think the reason some of these cars are still around is because they had frame/chassis issues since new and the owners hated driving them so they sat..

 

I know what you mean. I can see how certain structural/chassis issues can persist against all odds. Hmm there ain’t much left to replace on this vehicle. I might throw my hands up, admit defeat and get some guru to go over the vehicle.


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Well... are you gonna get 30 feet of C-channel and weld in X or lateral reinforcements?
That's next!

 

You said you changed the rear uni joint- how about the front one? Sounds like when it was converted to open drive, the tailshaft may be a tad too long, or, like you said, the diff is too far forward. Are the back wheels centered in the rear opening?

 

Grab the front yoke and see if you can move it up and down or side to side. If you can, you need a new bushing in the tail shaft or the yoke is warn.

 

Is the vibration there if you push in the clutch at 60 and coast?

 

(I’ve been chasing around a vibration in my 53 Chevy and it’s driving me nuts. When I get to about 60mph I get a vibration.)

(Now, when I’m accelerating the vibration is noticeable (blurry revision mirrors etc), but if I press the clutch in at speed, or back off the throttle the vibration is about twice as bad.)

Sounds like your problem might lay somewhere near here.
Did you go through the T5 yourself?
Even then,,,I have missed seeing problems before a recheck.
Sounds like a pilot shaft or clutch problem?

Tommy

 

You may not find it, my 36 has a vibration in the steering wheel at exactly 60 mph, for twenty years, I have done everything I and others can think of to find it, its part of the trucks character and I've given up looking. New wheels and tires, new driveshaft, new rear springs and shocks, new rotors, different gearing, still there.

 

What I do is... actually read the entire OP.

 

^^^^
"Egad Holmes, I believe you've got it!"
So when the diff. drives the "car", the vibe doubles...
Or with No torque input...

Look at fwd ujoint, tailshaft bushing, anything that permits looseness, mounts, misaligns.

 

That's what I'm thinking, possibly a loose or worn out pilot bushing.

 

It feels ‘heavier’ than a pilot bushing. And the pilot bushing is new. Come to think of it just about everything is new haha. I built a fresh 283 for this car. The T5 is old and the front yoke is old. In terms of the rear wheels, no they sit close to an inch forward, which bugs me, particularly since the leaves were part of the “bolt in” 54 Chevy kit supplied by chassis engineering. I figured that, since my car was Australian delivery, and assembled by Holden, they must have used Holden springs of a different length to stock Chevy ones. I can’t feel play in the front yoke trying to move it by hand, not to say that 2000 rpm at 0.63 overdrive couldn’t induce some... but the thing was balanced less than a year ago.


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I would check all your mounts trans engine cross member etc.

Body mount collapsed hitting the trans / engine/ exhaust ?

T5’s are somewhat common for input shaft bearing issues.

Clutch?
Flywheel ?

Pilot bearing? Or a bushing?
I have seen new bushings seize onto input shafts and cause vibration/ clutch issues.

Possible drive shaft/ u-joint issue as well
And don’t count out a bad part or balance
Some guys “do as they are told”
“Shorten the shaft OK! Naw I didn’t look at the I joints and yolk I was told to shorten the shaft”
I see it slot working in the trades unfortunately.

 

Let's talk about the rear gears. What ratio are they? Do you have a tach? What rpms at 60mph? Is the vibration exactly the same in 3rd,4th, and 5th at 60 mph? Maybe too high of final drive?