Problem: With the box empty, when going over a bump/pot hole/speed bump, can feel a “shudder" (rapid up and down motion with a slight lateral component) through the driver’s seat (no excessive bounce upon impact and/or roll and no front end “diving" upon braking).
In a more or less controlled setting, when driving over a single speed bump in a paved shopping plaza parking lot at about 25 mph, can sense that the “shudder" does not occur when the front wheels make contact with the speed bump. Rear wheels pass over the speed bump and cab/driver’s seat “shudders". Persists for 3-5 seconds.
Have replace the rear shocks with Monroe “Flex" as specified for the F150, 8200 GVW vehicle and there is only marginal, if any, improvement. Tried lowering tire pressure to 32 psi (rated at 65 psi when loaded to capacity) – no change. Leaf springs and shackles appear to be OK – no evidence of overloading on “overload bumpers". No evidence of twist/crack(s)/repairs to frame. Cab is free to float - no solid attachments between frame and cab. Checked all eight body mounts – one nut missing - have since replaced. No effect. “Rubber donuts" in cab body mounts appear to be in good shape with no damage or deterioration. Was told that it was in a “minor" accident (sheet metal damage only - $4,700 (Cdn)).
Has the cab ever been removed for maintenance or repair? Could have given evidence of one nut missing but don’t know.
Obviously don’t want to spend more money needlessly and I would appreciate any help/suggestions that you can give me.
have the same problem?
Thursday, June 10th, 2010 AT 8:48 AM