Odd Shaking

[pokeytom]

Ran through the the gears, about 5500 each. Then the cars gets a weird vibration, stop for a few minutes then seems OK. 1977 all back dated. New tires all balanced. What's going one, what do I look for? Vibration only happens when ran hard and faster then normal. Clues? Thanks guys

[RSBob]

Need more data. Describe where the vibration is coming from. What has changed if any thing before this started. Is the vibration subtle, jarring, or what? Any sound with the vibration? More data.

[pokeytom]

That's the odd part- nothing was done to the car before this started. After you get on it hard, run through the gears and take it up to say 75-90 mph, it begins to shake, feels like the rear somewhere. Seat of the pants shake. Feels like the flywheel out of round but that's not it. Like I said it shakes hard enough you pull over for a few minutes and when you take off again the shake is still there but less noticeable. Maybe rotors or brakes? Funny thing is it doesn't do it when you slowly run it up to the higher speeds. Throw me some ideas please.........

[mo-mon]

When you pulled over, was it still shaking when stationary & at idle?

Check motor mounts and engine support crossmember.

[pokeytom]

No shaking when stopped. Sitting at idle rev engine no shake very smooth.

[stownsen914]

How about if you rev to 5500 while standing still or in a lower gear? From your description, it sounds like it may be speed dependent, but revving a lower speeds could help rule out an engine issue.

Another thing to try - get up to speed and while experiencing the shake, put the trans in neutral and rev the engine up and down a few times to see if the shake changes.

These experiments may have distinguish between a vehicle speed dependent issue vs. an engine speed dependent issue.

[RedCoupe]

Inner CV joint bolts tight?

[pokeytom]

Well guys we figured it out. Calipers sticking oh so lightly, just enough to get the rotors hot when under heavy acceleration causing the shaking. 40 years old, time for some new parts. So while we were under there we ordered all the fun stuff. Bushings, bearings, brakes, shocks, rotors, calipers. (Calipers have been rebuilt, there're tired)...right down to the torsion bars.
We've got a little bit of Elephant and a whole lot of Pelican coming. Nothing's ever easy or inexpensive, right?

[Dmitry at Pelican Parts]

Originally Posted by pokeytom

Well guys we figured it out. Calipers sticking oh so lightly, just enough to get the rotors hot when under heavy acceleration causing the shaking. 40 years old, time for some new parts. So while we were under there we ordered all the fun stuff. Bushings, bearings, brakes, shocks, rotors, calipers. (Calipers have been rebuilt, there're tired)...right down to the torsion bars.
We've got a little bit of Elephant and a whole lot of Pelican coming. Nothing's ever easy or inexpensive, right?

Thank you for the continued support pokeytom, we appreciate it very much. Please let us know if there is anything else that we can help with!


-Dmitry