This month, I am writing on the rear multileaf spring upgrade for ’62-67 model Novas. These First-Generation cars used monoleaf springs to hold up the rear of the car. This setup was developed because it gave the cars a somewhat soft and comfortable ride overall. However, through the years, due mostly to wearing out, the single-leaf setup has proven to be a weak link, especially when it came to performance and handling.
How Smooth Do You Want Your Ride?
The spring rate on a multileaf spring with three leafs is close to the original monoleaf. This results in a ride similar to that of the original or monoleaf setup when new. Any increase in spring load weight will cause a harsher ride, so it’s important to get a multileaf spring that is close to the original monoleaf’s spring rate.
Why change to a multileaf setup? Aside from the previously mentioned ride characteristics, it’s not uncommon to find a stock monoleaf cracked or broken around one of the mounting eyes. This will most often go unnoticed unless you go looking for a problem, or you happen to undergo a rearend upgrade. Some of the additional benefits in converting to a multileaf are to restore comfort in the ride, maintain a good ride height, and preserve the correct travel in the rear suspension. If, in fact, you still have a ride height problem after replacing the stock monoleafs with multileafs, this can be addressed with aftermarket overload shocks. These overload dampers have coil springs wrapped around the shock body to handle the extra weight when needed without costing you the comfort of a good ride.
From a performance standpoint, switching to multileafs can positively affect the way your hot rod hooks up to the ground. With most stock Novas sporting a straight-six for power, a heavy-duty, rear multileaf spring wasn’t necessary. However, with the power that some people have under the hood of their Novas, the multileafs go a long way in helping to get that power to the ground by preventing coil twist and rearend squat.
The Air Shock Boost
Another type of boost is handled by air shocks__known by teenagers to be cool when raising the rear of their car. A lot of old car owners associate these with a terrible and harsh ride; the key to these is to only put in as much air as needed to address the added weight concerns. This will keep your Nova bumper from dragging under added weight and will also prevent you from losing the ride. Either way, it’s not like you are adding air shocks to a Cadillac and ruining the ride; the small Deuce rear suspensions could only supply a certain level of comfort anyway.
When upgrading to the multileaf system, plan ahead! There are four small bushings at the rear of each leaf (eight total per pair) that are integrated with the shackles (shackles are also available to replace the old, worn-out ones). The front of the rear leaf spring is a different story, however. If the front, larger bushings (four of them) have deteriorated over the years, the center-mount “washer bolt” might be a problem. If this fastener gets real loose, it can ruin the front mount that is welded to the structural subframe. The “washer” part of the bolt centers the front of the rear leaf in the frame bracket. If your bushings are found to be worn out, you may find some wear in the welded frame bracket, as well. Also, the shaft of the bolt can also deteriorate from moisture while inside the rubber bushing and can be difficult to remove. A pry bar and an air wrench can help by prying and turning in at the same time. (Catching the front bushings on fire like some do for the frontend control arms is not an option for the rear!) Along with the twelve bushings mentioned are four rectangular rubber pads that sandwich the top and bottom of the leaf where it mounts to the rear axle. These also need to be inspected and replaced if necessary. Adding the three leafs to the rear will also require adding longer bolts to make up for the thickness of the new springs. These are available, too. (Note: any bolts used must be at least a grade 8.)
Reproduction Monoleaf Springs
For the purist who wants to upgrade his classic’s ride to like-new condition, but still wants to retain the original single-leaf setup, there are reproduction monoleaf springs available that work well. And, with the recent popularity of station wagons, owners of ’62-67 models, who have been out of luck in the past in acquiring new rear leafs, can rejoice as there is good news ahead__there is a prototype for a multileaf spring being tested currently for those cars. Though there are slight differences in design, mounting the new leafs is the same for the wagons as it is for coupes and hardtops. Whichever you have, adding new leaf springs and hardware will provide your classic with years of cruising service.
My team and I look forward to helping you complete the car of your dreams.
Joe Grom Jr.