The 1949–1951 Mercury Car SuperSlide Multi-Leaf Rear Leaf Springs (Pair) by Posies provides a direct bolt-in rear suspension solution engineered specifically for iconic 1949, 1950, and 1951 Mercury passenger cars (Sedan, Coupe, Convertible).
Available in both stock OEM height (Part #310) and a 3" lowered stance (Part #305), these spring packs replace worn, stiff, or sagging factory multi-leaf packs to deliver superior ride comfort, axle control, and precise stance options for classic restorations and lead-sled customs.
Product Overview & Performance
Original late-1940s and early-1950s Mercury leaf packs suffer from metal-on-metal friction, rust accumulation, and binding over time, resulting in a harsh, rigid ride. Posies solves this by embedding their signature moly-nylon SuperSlide buttons between leaf tips. This eliminates leaf-on-leaf grinding and allows the spring pack to flex smoothly over bumps.
Whether restoring a factory-spec Mercury cruiser or building a low-slung custom, both spring options drop directly into original factory frame mounts and rear shackle locations without cutting, welding, or chassis modification.
Series Stance Options
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Part #310 (OEM Stock Height): Engineered to original factory dimensions to restore standard rear ride height, ground clearance, and suspension geometry.
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Part #305 (3" Lowered Drop): Lowers the rear profile 3 inches below original stock height for the classic lead-sled rake while maintaining full suspension travel.
Key Features & Design Highlights
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Direct Bolt-In Fitment: Mounts into original factory front frame hangers and rear shackle locations on all 1949–1951 Mercury chassis.
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SuperSlide Inter-Leaf Technology: Embedded moly-nylon friction-reduction buttons eliminate metal-on-metal squeaks, rust binding, and leaf drag for a noticeably softer, quieter ride.
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Pre-Installed Front Bushings: Comes complete with pre-pressed front spring eye bushings to streamline installation.
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American-Made Quality: Hand-assembled and tour-tested in the USA using premium high-tensile tempered spring steel with proven 100,000+ mile reliability.
Technical Specification Matrix
| Feature / Metric |
Technical Specification Detail |
| Manufacturer & Part # |
Posies Rods & Customs — P/N: 310 (Stock) / P/N: 305 (3" Drop) |
| Vehicle Application |
1949, 1950, and 1951 Mercury Passenger Cars (Sedan, Coupe, Convertible) |
| Stance Options |
OEM Stock Ride Height (#310) or 3" Rear Drop (#305) |
| Inter-Leaf Damping |
Moly-Nylon SuperSlide Friction-Reduction Buttons |
| Included Hardware |
Sold as Pair; Pre-Installed Front Spring Eye Bushings |
| Package Weight & Size |
Approx. 66.0 lbs per Pair (52.00" L x 11.00" W x 5.00" H) |
Installation Notes & Recommendations
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Associated Chassis Hardware: Replacing worn, original hardware during installation is strongly recommended. Posies offers dedicated replacement front eye bolt kits and rear shackles designed specifically for 1949–1951 Mercury chassis.
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Pinion Angle Verification: When dropping Mercury rear ends 3 inches with #305 springs, check drive shaft working angles to ensure proper pinion angle alignment.
