Spitfire '65 Spitfire MKII w/bad vibes

[DomCasual]

Problem: Rear end vibration beginning around 56 mph; diminishing at about 63 mph.

History: Approximately 15,000 miles since complete frame off restoration in '95. Right axle assembly w/associated u-joints and seals replaced 3/13; u-joint at diff replaced 6/13. Some improvement noticed.

I'm considering taking the propeller tube off and getting checked for straightness and balance before investing another $1500 on left side axle work.

All ideas / suggestions welcome.
Peter in Charlottesville

 

[LarryK]

Check tire balance.

 

[TR3driver]

That does sound more like a tire problem; could be a stiff spot instead of balance, or a wheel/hub that doesn't run true. But it certainly wouldn't hurt to have the driveshaft checked. One trick that might be worth trying is to install a worm-type hose clamp around the shaft (to change the balance a bit). Try it with the worm in 3 or 4 different locations around the shaft. If one position is better than another, the shaft is out of balance.

 

[Andrew Mace]

Something else that's pretty easy to do: put the rear of the car in the air, firmly secured on jack stands. Start the engine and run it in gear, and watch the wheels, hubs, axles, etc. for anything bent.

 

[DomCasual]

Thanks for the suggestions -- I should have mentioned that new tires plus two new wire wheels and splined hubs were installed 5/12. All wheels have been rebalanced three times and switched front to back twice with no noticeable improvement.

Peter G