Packard Forum Index » V-8 (1955-56)

My 55 400 suffers vibration between 30 and 40 mph. Tires balanced, no flat spots, drive shaft u-joints OK, can find nothing, however the camber on one front wheel is excessive. Today my mechanic noticed that the water pump seems loose but not leaking and that the power steering lines are moving, possibly as if the pump was pulsing. Has anyone ever experienced this behavior? The engine was not rocking or vibrating while these two events were occurring.

It's driving me nuts. Any help will be much appreciated.

Bernardi

If you rule out obvious things, Packard issued a service bulletin (56-T10 corrected) because of problems with vibration on 55 and 56 seniors. Their problem was at a higher speed -- around 60 -- because of the U joint angle. Their fix was minimal so It didn't take but a very little amount of angle being off to cause that problem. Wonder if there is any chance something has loosened or a worn bushing at the rear axle or torque arm mounts on your car is causing the driveshaft/rear axle angle to change up/down or side to side and vibration is manifesting at a lower speed.

Is the vib in the seat of your pants or up front? First thing to do is start the engine and for 40 or 60 seconds try to rev to the approx rpm in neutral standing still and vary rpm slowly up and down to recreate. If you do could be damper or the accessories like toy say. remove belts + try again If youcan prob is in eng as this eliminates all drivetrain and axles tires etc.If you cannot reproduce this way take the car out on the road with someone following behind look for bent rims axles bad tires shocks etc .

Thank you. Will do!

Bernardi