Grease Dispenser Buckets Without Wheels/Trolley

Frequently Asked Questions

What is a grease bucket pump and how does it differ from a grease gun?

A grease bucket pump is a stationary dispensing system that draws grease from a bulk container (3 kg to 20 kg) and delivers it under pressure through a hose and coupler. Unlike a handheld grease gun that holds 400-500 g of grease internally, a bucket pump connects to a much larger grease supply. This eliminates frequent reloading during multi-fitting service rounds. The STAR S-300 series develops up to 4,000 PSI and delivers up to 9 g per stroke, making it suitable for both refilling grease guns and direct point-to-point lubrication.

What pressure does the STAR hand operated grease bucket pump generate?

The S-300 series generates up to 4,000 PSI (275 bar) at the high pressure handle setting. Three variable positions are available: high pressure at 4,000 PSI with 4 g per stroke output, medium pressure at 3,000 PSI (207 bar) with 7 g per stroke, and high volume at 2,000 PSI (137 bar) with 9 g per stroke. The 4,000 PSI setting is sufficient to push grease through partially blocked or crusted fittings that resist standard grease guns rated at 6,000-10,000 PSI, because bucket pumps deliver sustained pressure over longer periods rather than brief peak bursts.

What is the output per stroke of the S-300 grease bucket pump?

Output ranges from 4 g to 9 g per stroke depending on the variable handle position selected. At high volume (2,000 PSI), the pump delivers 9 g per stroke for fast filling. At medium pressure-medium volume (3,000 PSI), output is 7 g per stroke. At high pressure (4,000 PSI), output drops to 4 g per stroke as force is concentrated for stubborn fittings. For context, a standard lever action grease gun delivers approximately 1 g per stroke, so even the high pressure setting delivers four times the volume per cycle.

How do I switch between high volume and high pressure on this bucket pump?

Adjust the variable handle to one of three marked positions without any tools. The handle mechanism changes the effective piston stroke length. Slide or rotate the handle selector to the HP (high pressure) position for 4,000 PSI / 4 g output, the MP-MV (medium pressure-medium volume) position for 3,000 PSI / 7 g output, or the HV (high volume) position for 2,000 PSI / 9 g output. The change takes effect on the next pump stroke. No need to depressurise or disconnect the hose.

How do I prime the S-300 grease bucket pump after filling?

Press the spring-loaded follower plate firmly onto the grease surface, then operate the handle 5-10 strokes until grease appears at the coupler tip. The follower plate's rubber edge creates a seal against the bucket wall, preventing air from entering below the plate. If air persists after 10 strokes, lift the follower plate slightly, press it back down to expel trapped air, and resume pumping. Priming is typically needed only after a fresh bucket fill or after the pump has been stored empty.

Can I use this grease bucket pump for excavator greasing?

Yes, the S-300 series is specifically designed for heavy equipment lubrication including excavators. A typical excavator has 20-50 grease fittings (boom pins, bucket pins, swing bearing, track adjusters). Using a 10 kg or 15 kg bucket (S-310 or S-315) provides enough grease for a complete service without refilling. The 2.2 m hose reaches fittings on the undercarriage and boom from ground level, and the 4,000 PSI high pressure setting clears fittings that have accumulated hardened grease between service intervals.

Can I use this bucket pump for transmission and differential refilling?

Yes, provided the transmission or differential uses grease rather than gear oil. Some agricultural and industrial gearboxes specify NLGI 00 or NLGI 0 semi-fluid grease for filling. The S-300 series is rated for NLGI 1, 2, and 3 greases. For NLGI 00/0 semi-fluid applications, the pump will work but may deliver at lower pressure due to reduced viscosity. For gear oil (liquid), use a dedicated oil transfer pump instead. Always verify the manufacturer's fill specification before using a grease pump for transmission service.

What NLGI grade grease works with the S-300 bucket pump?

The pump is compatible with NLGI 1, 2, and 3 greases, covering the vast majority of industrial and automotive lubrication applications. NLGI 2 (the consistency of peanut butter) is the most common workshop grease and flows easily through the pump at all three handle settings. NLGI 3 (firmer, like vegetable shortening) requires slightly more effort on the handle but works at all settings. NLGI 1 (softer, like tomato paste) flows freely and is common in centralised systems and cold-weather applications.

Why is my grease bucket pump not dispensing grease?

The most common cause is air lock: air trapped between the follower plate and the pump inlet prevents suction. To fix, press the follower plate firmly onto the grease surface and operate the handle 10-15 strokes. If grease still does not appear at the coupler, check that the follower plate rubber edge is intact and seated against the bucket wall. Other causes include a clogged coupler nozzle (remove and clean with solvent), worn piston seals (replace the seal kit), or hardened grease blocking the suction port (warm the bucket to soften the grease before pumping).

How do I troubleshoot a grease bucket pump that will not build pressure?

Start by checking the piston seal for wear; a worn seal allows grease to bypass the piston instead of building pressure. Remove the pump assembly and inspect the piston O-ring or cup seal. If the seal is cracked, flattened, or shows grease weeping past it, replace with the correct repair kit. Next, check the non-return valve (ball and seat) at the pump outlet; a stuck or scored ball prevents pressure from holding between strokes. Clean the valve seat with solvent and replace the ball if pitted. Finally, verify the hose connections are tight; a loose fitting bleeds pressure before it reaches the coupler.

Can I mix different types of grease in this bucket pump?

Mixing incompatible greases can cause softening, hardening, or separation that damages bearings and clogs the pump. Lithium and lithium-complex greases are generally compatible with each other. Calcium and lithium greases should not be mixed. Polyurea greases are incompatible with most other types. Before switching grease types, clean the bucket, follower plate, hose, and coupler thoroughly with a petroleum-based solvent. Pump solvent through the system until it runs clear, then refill with the new grease type. When in doubt, consult the grease manufacturer's compatibility chart.

How do I clean a grease bucket pump after use?

Wipe the exterior with a clean rag, then pump a small amount of grease through the hose to purge any air before storage. For a thorough clean (when switching grease types or before long-term storage), remove the follower plate and wipe the bucket interior. Flush the pump mechanism by filling the bucket with a small amount of petroleum-based solvent, replacing the follower plate, and pumping until solvent exits the coupler. Wipe all components dry and apply a thin film of fresh grease to the piston and follower plate rubber edge to prevent drying.

How should I store a grease bucket pump when not in use?

Store with the follower plate pressed onto the remaining grease surface and the cover closed to prevent contamination and moisture ingress. Keep the pump in a dry, sheltered location away from direct sunlight and extreme temperatures. In cold climates (below 5 degrees Celsius), grease stiffens and may require extra priming strokes on restart. In hot climates (above 40 degrees Celsius), grease can soften and separate; store in shade. If storing for more than 30 days without use, pump a few strokes weekly to keep seals lubricated and prevent the piston from seizing.

Can a grease bucket pump cause fluid injection injury?

Yes. At 4,000 PSI, grease can penetrate skin and inject into underlying tissue, causing serious injury that requires immediate medical attention. Never point the coupler at any body part. Never test for pressure by placing a finger over the outlet. Always depressurise the system before disconnecting the hose or coupler. Wear safety glasses and heavy-duty gloves when operating. If grease is injected under the skin, seek emergency medical treatment immediately; do not wait for symptoms to develop. Injection injuries can cause tissue necrosis if untreated within hours.

What is the difference between the 3 kg, 6 kg, 10 kg, 15 kg, and 20 kg bucket pumps?

The only difference is the bucket size; the pump mechanism, pressure rating, output per stroke, and hose length are identical across all seven models. Choose based on daily grease consumption: 3 kg (S-303) for light workshop use with 5-10 fittings per day, 6 kg (S-306) for general automotive service, 10 kg (S-310) for construction equipment with 30+ fittings, 15 kg (S-315) for heavy equipment depots, and 20 kg (S-320) for large fleet operations or multi-shift facilities where a single fill must last several days.

Can I use this bucket pump to refill handheld grease guns?

Yes, refilling grease guns from a bucket pump is one of the primary uses of the S-300 series. Remove the barrel from your grease gun, connect the bucket pump coupler to the gun's loader fitting (or use the suction method with the barrel submerged), and pump at the high volume setting (9 g/stroke, 2,000 PSI) until the barrel is full. This is significantly faster than loading individual cartridges and reduces per-fill cost by 40-60% compared with pre-packed cartridges. One 10 kg bucket refills approximately 25 standard 400 g grease gun loads.