S-703E Mini Lever Action Grease Gun - Slim Barrel 8 oz. / 200 cc

Frequently Asked Questions: Slim Barrel Mini Lever Action Grease Gun 8 oz

What is the advantage of a slim barrel grease gun?

A slim barrel grease gun reaches fittings in tight spaces where wider guns cannot fit: between frame rails, under fairings, behind engine accessories, and in compact implement housings. The S-703E combines a 44.45 mm slim barrel (same as the S-702) with 8 oz. (200 cc) bulk capacity, giving the best of both: narrow profile for access plus enough grease for a full service session. The trade-off: slightly longer priming time than wider mini guns because of the longer grease column in the narrower barrel.

What is the difference between S-703E (6000 PSI) and S-703 (3000 PSI)?

Both are 8 oz. (200 cc) mini lever guns, but the S-703E generates 6,000 PSI with a 44.45 mm slim barrel, while the S-703 generates 3,000 PSI with a 50.80 mm wider barrel. Use the S-703E when you need high pressure for sealed bearings, crusted zerks, or tight-space access. Use the S-703 for general-purpose greasing where 3,000 PSI is enough and you prefer a wider barrel for faster bulk filling. Both share the same 8 oz. capacity, same 0.55 g/stroke output, and same hose/extension accessories.

How many strokes does it take to deliver 1 oz. of grease?

The S-703E delivers 1 oz. (22 grams) per 40 strokes, or 0.55 grams per stroke. At full 8 oz. capacity, the gun holds approximately 360 strokes of grease. For service planning: typical chassis fitting = 3-5 strokes (1.5-3 g); tie rod end = 2-4 strokes; sealed bearing via zerk = 10-15 strokes; drive shaft slip yoke = 8-12 strokes. Count strokes to match equipment service manual grease-per-fitting specifications.

How do you fill a grease gun from a grease cartridge versus bulk?

The S-703E is a bulk-fill and suction-fill only design (no cartridge slot). This is intentional: cartridge compatibility requires a specific inner barrel diameter (about 38 mm), and the S-703E's 44.45 mm slim barrel uses that space for 25 percent more grease capacity. For cartridge compatibility in the same form factor, consider a standard 14 oz. gun like the S-707 which accepts industry-standard cartridges. Bulk filling is cheaper per gram (10-15 percent lower cost) and uses less packaging.

How do I bleed air from a mini grease gun?

To bleed air from the S-703E: loosen the head 1/4 to 1/2 turn while pumping the lever slowly; air will hiss out first, followed by a bead of grease confirming the air is cleared. Retighten the head fully and continue pumping until grease flows steadily from the coupler. The S-703E's longer slim barrel makes it more prone to air pockets than shorter minis, so bleed after every bulk refill. If air keeps returning, disassemble, manually pack grease against the follower plate, and reassemble.

Can I use a mini grease gun in a tight engine bay?

Yes, the S-703E's 44.45 mm slim barrel is designed for tight engine bays, compact engine compartments and behind-accessory fittings. Common tight-space applications: starter motor bushings, alternator pivots, distributor shafts (on older vehicles), clutch cable pivots, accelerator linkage pivots, and steering box fittings. Pair with the 10 inch flexible hose to reach fittings behind rigid components without repositioning the gun. The slim barrel also fits in most OEM toolkit holders designed for compact tools.

Can I use a mini grease gun on ball joints and tie rod ends?

Yes, ball joints and tie rod ends are primary applications for the S-703E. These fittings typically accept 2-4 strokes until fresh grease shows at the boot seal. Stop immediately when fresh grease appears. Over-pumping blows the rubber boot seal and shortens joint life. Use NLGI 2 lithium or moly-fortified grease for standard applications; use polyurea for sealed-for-life joints that still have a zerk. Sealed "lifetime" ball joints without zerks cannot be greased and must be replaced when worn.

Can a mini grease gun break through clogged grease fittings?

Yes, the S-703E's 6,000 PSI is high enough to force grease through most clogged or crusted zerk fittings. Before pumping aggressively: (1) clean the zerk exterior with a wire brush and penetrating oil to remove crust; (2) try a needle-point grease adapter if the ball check appears damaged; (3) verify the internal ball check is not seized closed; (4) replace the zerk if the internal check is stuck. Never exceed reasonable lever force. If the lever goes hard, the fitting is permanently blocked and needs replacement.

Why does my slim barrel grease gun lose prime more often?

The S-703E's long slim barrel is more prone to prime loss than shorter minis because air trapped at the follower plate takes more strokes to clear. Causes of repeated prime loss: (1) loose head threads letting air re-enter between uses; (2) worn plunger rod seal; (3) incomplete bulk fill leaving an air pocket near the closed end; (4) grease separation (oil bleeding out) after long storage. Fix: tighten head firmly after each refill, inspect/replace the plunger rod seal if worn, bulk-fill slowly with the plunger held back until grease reaches the top, and flush/reload if grease has separated.

How do I replace a worn seal on a grease gun?

The S-703E uses a plunger rod seal, a head o-ring, and a follower plate seal, all replaceable with standard service parts. To replace: (1) empty the gun and disassemble via the demountable bottom cap; (2) remove the plunger rod by unscrewing the plunger nut; (3) pry the worn o-ring or plunger seal off with a non-sharp pick (avoid scratching the metal groove); (4) wipe the groove clean; (5) lightly grease the new seal with fresh grease; (6) press the new seal into place by hand; (7) reassemble and test. Spare seal kits are available from STAR.

What happens if I mix polyurea and lithium grease?

Polyurea and lithium greases are generally incompatible and can form hard deposits, lose consistency, or separate into oil and solids when mixed. Polyurea (common in sealed electric motors and high-temperature applications) uses a completely different thickener chemistry than lithium (common in automotive and general-purpose grease). If accidentally mixed in the S-703E: fully disassemble, solvent-flush with naphtha or mineral spirits, dry, lightly re-grease the seals, and reload with a single grease type. Keep separate guns for different grease chemistries in workshops handling both.

When should I service the grease gun internals?

Service the S-703E internals every 6 months for occasional use, every 2-3 months for weekly professional use, or whenever you switch grease types. Internal service: (1) disassemble via the demountable bottom cap; (2) wipe out old grease with a clean rag; (3) flush with solvent if hardened; (4) dry completely; (5) lightly re-grease the plunger seal and o-rings with fresh grease; (6) reassemble. Also inspect the 10 inch hose for cracks, bulges or crimp leaks at each service, and replace the hose every 12-24 months in daily professional use. The S-703E's longer slim barrel accumulates more residual grease than shorter minis.

How should I store the S-703E between uses and in cold weather?

Store the S-703E horizontally (laying flat) with the plunger rod disengaged, in a clean dry area at 5-35°C. Horizontal storage prevents oil bleed; vertical nozzle-down storage accelerates oil separation. Disengaging the plunger releases follower spring tension and extends spring life. Cold-weather operation: switch to NLGI 1 grease below -10°C, warm the gun to at least 10°C before use, store indoors (not in an unheated shed). Hot-weather storage: keep below 40°C to prevent seal aging and grease hardening in the long slim barrel. For storage over 3 months: wipe exterior, remove coupler, cap the outlet.

How do I avoid a grease injection injury?

Always wear safety glasses and nitrile gloves, and never place your hand or body in front of the coupler tip or a pressurized hose. A 6,000 PSI grease injection injury is a medical emergency: grease injected under the skin can cause severe tissue damage, infection or amputation even from a tiny entry wound. If injection happens, go to an emergency room immediately and tell staff it is a high-pressure grease injection injury. Inspect the hose before every use for cracks, bulges or kinks. Never bypass the coupler or press the gun tip directly against skin or a seal. Keep the gun pointed away from your body when priming.