Most of the cars we write about here at Mopar Muscle are some 30 to 40 years old, and with age comes the requirement to replace the parts of these cars that are designed to wear. Many suspension and steering components fall into this category and require regular replacement and maintenance to keep the car safe and performing like new. Two parts of the rear suspension that not only require replacement, but can also enhance performance, are the rear leaf springs. Despite what your neighbor might tell you, if your leaf spring equipped Mopar is sagging in the rear, air shocks won't fix it. The only way to properly address this problem is by replacing the rear leaf springs.
Since our '69 Chrysler Newport was showing some 160,000 miles, and a sagging rear, we decided to install new rear springs. Performance Suspension Technology (PST) has been building quality Mopar suspension and steering parts for years, and hasn't neglected the Mopar C-Body. We found they not only had replacement leaf springs for our car, but had heavy-duty, staggered, Hemi-style leaf springs that would bolt directly in place of our worn original units and offer better performance.
Replacing your Mopar's leaf springs is a fairly easy weekend job, requiring basic hand tools, a jack, and a couple of jack stands, or a lift and transmission jack to support the differential. Our original springs were actually arced in the wrong direction behind the axle housing, and our car was noticeably low in the back. The PST leaf springs are a heavier-duty design than the factory springs, containing seven individual leafs compared to the original spring's five leafs. They also come with new bushings and all the hardware to complete the job including new U-bolts.
Once the new PST leaf springs were installed, the rear ride height of our Newport was raised by some two inches, and the car's stance looked more like it did when new. The PST springs are stiffer than the originals, but ride quality is still very nice and our car's handling improved noticeably thanks to the new springs and bushings. At the track...yes, we took our convertible C-body to the track...our Newport had previously suffered from roll rotation (right rear of car squats), and the new springs not only solved the problem but produced slightly better sixty foot times as well. We always consider suspension upgrades as perhaps the most noticeable of all automotive enhancements, because they affect you any time you drive your car. This leaf spring upgrade is no exception, helping our big Chrysler ride and perform better than it did when new.
1 The PST spring (top) is...
1 The PST spring (top) is noticeably more rugged than the original leaf spring. It also contains seven individual leafs compared to the stock spring's five leafs.
2 All new hardware, bushings,...
2 All new hardware, bushings, and even U-bolts are included with the PST leaf springs, so even if you have to cut some of the old hardware to remove it, you'll have what you need for reassembly.
3 Removing the original leaf...
3 Removing the original leaf springs is pretty straightforward, and requires removing the forward spring mounting bracket. This bracket is removed and placed on the new springs prior to installation.
4a The original spring had...
4a The original spring had lost its arch, and was actually arched the wrong way, making our Newport sit low with poor ride quality and handling.
4b The new PST spring is...
4b The new PST spring is properly arched, returning our car to its original ride height.
5 We took our Newport to...
5 We took our Newport to the Lakeland dragstrip for some testing, and on our first pass noticed an improvement in the way the big car launched. Sixty foot times were improved to 2.48 seconds from a previous best of 2.55 seconds.