I have a 67 400 convertible that I have just recently noticed the passenger side is about 1/2" lower than the driver side. Up until this point the car has been level, so the first thing I checked was the rear leaf springs because they are known to crack around the centering pin. I have been unable to find any signs of a crack or the springs being otherwise compromised, and the bushings seem to be in good condition. If anyone has any ideas, or has experienced this and rectified it, the help would be greatly appreciated. I also redid the front suspension and steering 2 winters ago and replaced the coil springs, could any of those components be the cause? It just seems odd that the car would sit a half inch lower just within the past month, than sooner if that were the case.
Also, the previous owner who restored the car put 5-leaf rear springs on the car. I know 67 had mono springs only, but if going with the 4 or 5-leaf setup, doesn't the 400 get 4-leaf springs? If so, could anyone recommend a good brand of HD springs...it has a tendency to bottom out with passengers in the rear. Thanks!!
Not to be a smart-a$$, are the tire pressures equal? Or perhaps you have a failed bushing?
Yes, I have a 400 and they came with the performance 4-leaf springs. The spring rate is 126-130 in/lbs, whereas the 5-leaf is rated lower at 89 in/lbs. I just installed a set from General Spring [in Kansas] - they have nice selection and competitive prices. I'm waiting for a part, so I haven't driven it yet...
Could be in the front end. If the front right side is sagging and lower the rear left would be higher. Jack up the front of the car in the center subframe with a jack to get the weight off the front end. Then measure the rear on both sides. If they are the same then the problem is in the front, if they are different then the problem lies in the Rear suspension.