On a 1957-'64 jacking under the rear end should be ok as they have a fabricated weldment for the housing which should be fairly rigid (no guarantee). On 1965 and up you should not do that as the rear end utilizes pressed in axle tubes that have one plug weld to prevent the rear end from rotating (it won't stop it from bending with much more than 450 horse power however so I recommend welding the center section solid). If you pick it up under the differential case it will bend the rear end.
hey just wondering, what would be the best places to put the floor jack and jack stands on a 64 impala front and rear? thanks wade
I have been wondering about this myself . Since I am doing lots of work on the underside, my Impala is spending a fair amount of time up on jack stands, and one can't help but wonder if improperly placed jack stands could be bad for the frame. What I have come up with is this.
In front, I use the floor jack on the center of cross member that passes under the engine. I then use jack stands on the frame between the front suspension and the bumper area, but on the fully boxed frame area (not the C shaped part that is furthest forward and connects to the bumper). It seems to me the C shaped frame area would not be a strong and possibly be dented or bent by the jack stand. It is a tight fit on the drivers side as the jack stand is competing for space with the power steering hoses.
In the rear, I do one side at a time. I use the floor jack on the area where the bumper mount branches off the frame in a kind or Y shape. The metal is thicker here. I can then mount the jack stands just to the rear of the axle on the fully boxed frame, just after the frame has become level from the bend over the axle. An alternate that would get more lift out of the floor jack would be to use the floor jack just forward of the rear axle on the frame (one side at a time). In my garage, I dont have good access to the drivers side of the car, so I use the bumper end.
I do find the car shifts around as it is jacked with the floor jack (its on wheels). So after putting in the second pair of jack stands double check the first pair of jack stands to be sure they are still planted securely. I find this gives me sufficient clearance to get under the car with a creeper. Now if only my eyes could still focus up close .
Stumbled across this recommedation in my 1961 Shop Manual. Somehow if feels safer with the jacks closer to the corners But I suppose Chevrolet's way puts less bending stress on the frame and puts the weight bearing spots on stronger parts of the frame..