S-708/N Lever Action Grease Gun

Frequently Asked Questions: Lever Action Grease Gun

What is the best lever grease gun for marine and coastal environments?

Four features separate professional lever guns from commodity guns: pressure rating, finish durability, cartridge compatibility and volume per reload. On the S-708/N: 6,000 PSI (413 bar) working pressure for standard service, chrome-plated barrel for corrosion resistance in marine and humid plant environments, standard 57.15 mm barrel accepting 14 oz. (400 g) cartridges, and 2X-volume extended barrel that delivers twice the grease per reload versus standard-length 14 oz. guns. The chrome finish outlasts painted and powder-coated finishes in coastal, dairy-plant and food-processing environments where protective coatings get abraded or chemically attacked.

Is a lever grease gun better for marine applications?

Yes, when the gun finish resists salt-spray corrosion. The S-708/N's chrome-plated barrel is designed for marine and coastal service where painted finishes blister and powder-coated finishes chalk over time. Marine applications on the S-708/N: boat trailer wheel bearings, outboard motor fittings, marina crane service, dockside handling equipment, commercial fishing vessel linkages, shipyard tooling. The 6,000 PSI pressure is adequate for the zerk fittings typical in these applications. The chrome finish is the differentiator from standard-finish lever guns. For coastal or marine service requiring higher pressure at 10,000 PSI tiers, the aluminium-head S-710DC combines aluminium corrosion resistance with higher pressure.

How does a 6,000 PSI lever gun compare to a 10000 PSI model?

6,000 PSI handles 90 percent of standard automotive, agricultural and light-industrial service; 10,000 PSI adds margin for heavy-duty outdoor-equipment fittings that develop crust. For the S-708/N's target applications (marine service, food-processing plants, dairy operations, automotive workshops), 6,000 PSI is the appropriate working pressure. Fittings in these environments are generally well-maintained and easy to seat grease into. The chrome finish prioritizes corrosion resistance over pressure margin. For mining, construction and extended-outdoor-service applications where fittings develop contamination, step up to 10,000 PSI models like the S-707 or S-724 with heavy-duty construction and Quadra-Cut steel heads.

What is the capacity of a standard lever grease gun?

The S-708/N is the 2X-volume variant of the S-708 platform, delivering approximately 28 oz. (800 g) per reload versus the standard 14 oz. (400 g) capacity on base S-708 guns. The extended-barrel design doubles the reservoir volume while maintaining the standard 57.15 mm barrel diameter for 14 oz. cartridge compatibility. The gun accepts either a standard 14 oz. cartridge (using half the barrel) or two cartridges stacked end-to-end, or a full bulk fill equivalent to two cartridges. For operators wanting longer runs between reloads on workshop and marina service, the 2X-volume capacity reduces reload frequency by half. The chrome-plated finish maintains corrosion resistance across the extended barrel length.

How do you bulk load a high-volume lever grease gun?

Load the S-708/N from either a 14 oz. Cartridge, two stacked cartridges, or a bulk pail. Single cartridge fill (uses half the 2X-volume barrel). Retract and lock the plunger rod. Next, unscrew the barrel. Then, peel the metal pull-tab. After that, insert nose-first. From there, peel the plastic bottom seal and screw the head back on. Finally, release the plunger rod. Bulk fill (full 2X capacity): (1-2) same. Then, dip the extended barrel into a grease pail and pack firmly for the full barrel length . Extended barrels take 40-50 percent more packing time than standard barrels . After that, screw the head on. From there, release the plunger. Finally, crack the head a quarter turn. And last, pump 5-8 strokes to bleed air, retighten.

How many grams of grease per stroke does a lever gun deliver?

The S-708/N delivers 1 gram per stroke, or 1 ounce per 28 full-lever strokes. A full 2X-volume bulk fill delivers approximately 800 grams across 800 full-lever strokes. For service planning on the S-708/N: a 20-gram fitting shot needs 20 lever strokes, a 30-fitting workshop-day coverage needs 600 strokes, a 2X-volume fill covers 40 fittings per reload. Stroke-count planning works precisely on the S-708/N because output is constant across the full extended reservoir. The chrome finish does not affect pumping mechanics. For precision dispensing applications (small dab amounts per fitting), count strokes individually. The 1-gram precision is adequate for most professional service.

How do you prime an extended-barrel lever grease gun?

Prime the S-708/N in four steps after every reload. Ensure the head is screwed snug against the chrome barrel. Next, crack the head a quarter turn to open the bleed path. Then, with the coupler disconnected, pump the lever through 5-8 full strokes to purge air from the 2X-volume extended reservoir. After that, retighten the head once grease flows from the head seam without bubbles. The extended-barrel design needs 5-8 priming strokes versus 3-5 on standard 14 oz. Guns because the longer reservoir has more internal volume for air to occupy during bulk packing. Cartridge fills prime faster than bulk fills because cartridges have no internal air voids. Never prime against a connected fitting. Air must escape at the head, not into a bearing.

How do you clean a lever action grease gun?

Clean the S-708/N in seven steps for routine service. (1) Depressurize by retracting the plunger rod and pressing the bleeder valve. Next, Empty the reservoir through the coupler into a waste container. Then, Unscrew the head and remove any remaining grease. After that, Wipe the chrome barrel interior with solvent-dampened lint-free rag . Reach the full 2X-volume barrel depth since extended barrels retain more debris. From there, Solvent-clean the head internals and non-return valve. Finally, Inspect the plunger rod seal for circumferential wear. And last, Reassemble with fresh grease. Never use abrasive cleaners on the chrome exterior. They scratch the chrome plating. Wipe the chrome exterior with a soft cloth and mild detergent only.

How do you prevent grease from hardening inside a lever grease gun?

For regular professional workshop use (2-5 reloads per shift), clean the S-708/N every 6 months. For marine and coastal environments, every 3 months because salt-spray exposure accelerates contamination. For food-processing and dairy-plant use where wash-down chemicals may enter the gun barrel during cleaning cycles, every 60 days. The chrome-plated finish resists external corrosion but contamination inside the barrel still accumulates from grease oxidation and moisture ingress. Cleaning schedule is driven by operational environment, not by the chrome finish. Chrome reduces external maintenance, not internal service frequency.

Can I mix different types of grease in my tractor fittings?

No. Mixing grease chemistries causes thickener separation that can damage bearings downstream. Lithium complex, calcium sulphonate, aluminium complex and polyurea thickeners all use different chemistry. Combining them forms slurry. To change grease types in the S-708/N: empty the 2X-volume reservoir completely, unscrew the head, wipe the extended barrel interior with solvent-dampened rag, solvent-clean the head internals and non-return valve, reassemble with the new grease and prime per the procedure. For marine-service applications where calcium sulphonate or aluminium complex chemistries dominate, dedicate one S-708/N to the marine grease type. For food-grade applications requiring H1 or H2 certified greases, dedicate another S-708/N exclusively to that chemistry.

What causes air lock in a high-volume grease gun reservoir?

Air lock on the S-708/N has three causes. Incomplete bulk-fill packing leaving voids in the extended 2X-volume reservoir. Next, swapping cartridges mid-partial-fill so air fills the space above. Then, leaving the plunger rod retracted-and-locked between uses so grease settles away from the follower. Extended barrels are more prone to bulk-packing voids than standard barrels because the longer packing action allows air to get trapped at the barrel sidewalls. Prevention: use a scoop or spatula when bulk-packing and work grease against the barrel sidewalls to eliminate voids. Cure: bleed air per the standard bleed procedure using the tilt technique to help air rise to the head where it escapes through the bleed gap.

Why is grease leaking from the barrel threads of my lever grease gun?

Thread leaks on the S-708/N have two common causes. Head not fully tightened to the barrel after reload. Next, worn thread sealing surfaces from repeated reload cycles. Fix sequence: confirm the head is threaded fully home with the gasket or sealing surface compressed . On rolled-thread barrels the seal is easy to seat fully. On worn threads it may require extra force. Inspect the mating threads on both the head and barrel for galling, cross-threading or stripped shoulders. For chronic thread leaks, the head sealing surface may need cleaning. Wipe with solvent and check for flat, undamaged mating surfaces. Replace the head or barrel if thread damage is extensive. The chrome plating does not affect thread function. It is on the barrel exterior only.

What should I do if a grease gun punctures my skin?

Mandatory PPE at 6,000 PSI (413 bar): wraparound safety glasses, nitrile chemical-resistant gloves, closed-toe work boots and long-sleeve protective clothing. Safety rules: never point the coupler or flex hose at any body part, keep the lever-hand behind the coupler head, inspect the flex hose before each use for cracks or bulges, never test grease flow by pressing the coupler against skin or fabric. The S-708/N operates below the 7,000 PSI threshold above which amputation risk from grease injection injury rises sharply, but injection injury at 6,000 PSI is still a surgical emergency. Any suspected injection injury requires immediate hospital treatment regardless of wound appearance.

How does a 6,000 PSI lever gun work for marine service?

The S-708/N delivers 6,000 PSI (413 bar) which positions it as a standard-duty lever gun rather than a heavy-duty model. Heavy-duty lever guns deliver 10,000-12,000 PSI with reinforced head construction. The S-708/N is the corrosion-resistant standard-duty choice for marine, dairy, food-processing and automotive workshop service. For applications requiring heavy-duty pressure margin (mining, construction, extended outdoor equipment service), pick the 10,000 PSI S-724DC or 12,000 PSI S-707 instead. The S-708/N's advantage over heavy-duty guns is finish durability and extended capacity. If those matter more than pressure tier, the S-708/N is the pick.

Should I apply grease to the o-rings when storing?

Store the S-708/N horizontally with the plunger rod disengaged for any period over a week with grease loaded. Oil bleed happens faster in partially-loaded extended barrels because the longer reservoir exposes more grease surface area to gravity-driven oil separation. Horizontal storage minimizes settling. Releasing the plunger rod from the side-slot lock lets the follower spring compress the grease column. For marine-service storage specifically: the chrome finish protects the barrel exterior from humidity but the gun should still be wiped dry before storage to prevent surface water pooling that can eventually compromise even chrome-plated surfaces. Store at 10-30°C in a clean workshop cabinet.

How do you inspect a grease gun hose for safety?

Inspect the S-708/N's 12" flex hose before each use for four failure modes. Cracks in the rubber sheath. Next, bulges along the hose length. Then, stiffness or hardening that reduces flexibility. After that, leakage at the crimped end fittings. A failed hose can burst under 6,000 PSI and cause grease injection injury. Any visible cracks, bulges or stiffness are grounds for immediate hose replacement. Do not continue using a marginal hose. The hose fatigues from repeated flexing at the same point, from UV exposure in outdoor use, and from chemical exposure in plant environments. Replace every 2-3 years in continuous outdoor or plant service. Replacement hoses are standard spares in the STAR spare-parts kit.

What does 40:1 pressure ratio mean?

40:1 pressure ratio on the S-708/N means operator input force at the lever is multiplied 40 times at the coupler output; 150 PSI of lever-arm input produces 6,000 PSI at the fitting. Pressure ratio is a fixed mechanical property of the lever geometry and piston area. It does not vary with operator technique or grease type. The 40:1 ratio is the industry premium tier for lever grease guns. Lower ratios (15-20:1) are typical on pistol-grip guns and cannot develop 6,000 PSI from reasonable hand input. The S-708/N shares the 40:1 ratio with all STAR lever action grease guns regardless of pressure tier. The 40:1 multiplier is the lever-action advantage over pistol grips.