Aftermarket Electric Grease Pump Model SK-505BM for Progressive Centralized Lubrication
This page describes a direct aftermarket replacement for the IHI SK-505BM electric grease pump used on small to medium machinery with progressive centralized lubrication systems. It is a motor-driven piston pump built to match the common mounting envelope and electrical connection for on-vehicle applications subject to vibration and rain exposure. IHI is a trademark of its respective owner. This is an aftermarket pump, not manufactured, sponsored, or endorsed by IHI. SK-505BM designations are for cross-reference identification only.
Before ordering, verify your existing model code and outlet fitting, because small differences in reservoir size or controller type will affect installation. The pump uses a 24V DC motor and a single outlet for a progressive divider valve connection. If your current unit has a different outlet thread or controller signal, see the grease pump selection notes before placing an order.
How the Pump Works
The SK-505BM moves grease by a piston driven from a 24V DC motor. The motor receives a simple ON/OFF power signal in the standard model, which is common for equipment with an external machine controller. When power is applied, the piston discharges grease from the single outlet into a progressive divider valve. When the divider cycles, it distributes grease in measured amounts to each lubrication point on the machine.
A transparent plastic reservoir holds the grease, and a heavy follower plate sits directly on top of the grease surface. The follower plate prevents cavitation by keeping the grease pressed down toward the pump inlet as the level drops. This matters for NLGI 000 and 00 greases, which can otherwise form a void around the inlet. For a broader explanation of pump selection, read a complete guide to grease pump before finalizing your controller choice.
The outlet thread is 1/4 inch BSPP with compatibility for an inverse flare fitting. An adapter for 1/8 inch NPT is available separately. The pump has one outlet only, so do not split the line before the divider valve.
Specifications
The declared specifications below are the baseline values for this aftermarket SK-505BM equivalent. Use them to compare with your current pump data plate. Confirm any value not listed before ordering.
| Pump type | Motor-driven piston pump |
| Motor voltage | 24V DC |
| Motor power | 25 W |
| Motor current | 1.5 A or less at rated load |
| Maximum discharge pressure | 14.7 MPa (2,100 psi, 150 kg/cm2) |
| Discharge capacity at free flow | 13 cm3/min or more |
| Discharge capacity at 14.7 MPa | About 6 cm3/min |
| Reservoir options | 0.4 L (400 cc) or 1.0 L (1000 cc) |
| Reservoir material | Transparent plastic with heavy follower plate |
| Grease grades | NLGI 000, 00, 0, and 1 |
| Outlet | Single outlet for progressive divider valve connection |
| Outlet thread | 1/4 inch BSPP, inverse flare compatible, adapter available for 1/8 inch NPT |
| Duty cycle | Maximum 5 minutes ON, minimum 5 minutes OFF |
| Operating temperature | -1 to +38 C for NLGI 000 and 00, +10 to +38 C for NLGI 1 |
| Weight | About 1.8 to 2.0 kg for 0.4 L version, 2.0 to 2.1 kg for 1 L version |
| Lubrication points | Up to 60 when paired with BU-M or BMUM progressive distributors |
| Standard control | Simple ON/OFF power signal |
| Optional controller | AGT (Auto Greastar) package with programmable controller and built-in timers |
| Optional low-level switch | Add suffix -LLS to model code |
| Model codes | SK-505BM-04 for 0.4 L, SK-505BM-1 for 1.0 L |
The pump is designed for on-vehicle applications subject to vibration and rain exposure, and for small to medium machinery. For system layout with a divider valve, the pump pairs with progressive distributors rather than a direct point-to-point line. See progressive lubrication systems for divider selection and port assignment.
Duty Cycle and Cooling
The SK-505BM has a strict duty cycle of maximum 5 minutes ON followed by minimum 5 minutes OFF for cooling. The motor is not rated for continuous operation, even if the grease line is blocked or the divider is slow to cycle. Running the pump beyond the 5 minute ON window will cause thermal damage to the motor windings.
In a typical progressive system cycle, the pump reaches pressure, the divider cycles, and the machine controller removes power. If your system requires longer run time, split the lubrication events into multiple short cycles rather than one long continuous run. The minimum 5 minute OFF interval must be observed even when the pump feels cool to the touch.
Because the pump is installed on vehicles and equipment with vibration and rain exposure, the motor housing should be kept clear of mud buildup. Do not wrap the pump in insulation or cover the motor during operation. Confirm the correct duty cycle for your machine controller before ordering.
Controllers and Options
The standard SK-505BM runs on a simple ON/OFF power signal from the machine control system. You supply 24V DC, and the pump runs until the signal is removed. The standard model code does not include a low-level switch, so monitor reservoir level by sight through the transparent body.
The AGT package, identified as Auto Greastar, adds a programmable controller with built-in timers. With AGT, you can set pause and run intervals without an external machine signal. This is useful for machinery without a spare controller output or for retrofit installations. The AGT package still follows the same duty limit and does not change the pump output or pressure rating.
A low-level switch is optional on either version. To add it, use the suffix -LLS, so the codes become SK-505BM-04-LLS or SK-505BM-1-LLS. The switch sends a contact signal when the grease level drops near the follower plate. Do not assume the switch is included unless the model code carries the -LLS suffix.
Grease Grades and Temperatures
This pump accepts NLGI 000, 00, 0, and 1 greases in the reservoir. The operating temperature window is -1 to +38 C for NLGI 000 and 00, and +10 to +38 C for NLGI 1. Do not operate below the lower temperature for a given grease grade because the pump may cavitate or the motor may stall at cold start. Confirm the ambient temperature range for your machine before ordering.
For cold weather use, NLGI 000 or 00 is the appropriate choice within the declared temperature window. NLGI 1 grease is workable only from +10 C upward. The follower plate cannot overcome the viscosity increase of an overly stiff grease in cold conditions. If your site runs below -1 C, use a lower-temperature grease system or confirm a different pump arrangement before ordering. To check a specific machine controller signal, contact the team with your pump model code.
Do not mix grease grades in the reservoir without cleaning the pump body and follower plate. A thickened layer at the inlet can block the piston discharge and produce uneven divider cycling. A hardened grease lump can travel into the progressive divider and may jam a port.
Frequently Asked Questions
Will this pump fit my existing IHI SK-505BM mounting?
Fitment depends on your reservoir size, outlet thread, and controller signal. Confirm the model code on your current pump before ordering.
Should I choose the 0.4 L or 1.0 L reservoir?
Choose based on your grease consumption per service interval and available mounting space. The 1.0 L body weighs slightly more and holds more grease between refills.
Can this pump run continuously like a small transfer pump?
No, the duty cycle is maximum 5 minutes ON followed by minimum 5 minutes OFF. Continuous operation will cause thermal damage to the motor.
What grease should I use for winter operation?
Use NLGI 000 or 00 grease within -1 to +38 C. NLGI 1 grease is acceptable only from +10 C upward.
Does this pump include the progressive divider valve?
No, the pump includes only the motor, reservoir, follower plate, and single outlet. Pair it with BU-M or BMUM progressive distributors for point distribution.
What outlet thread does this pump have, and is an adapter included?
The outlet thread is 1/4 inch BSPP, inverse flare compatible. An adapter for 1/8 inch NPT is available separately.
Is the low-level switch included on the standard model?
No, the low-level switch is optional and requires the -LLS suffix. The standard model does not include the switch.
What is the difference between the AGT package and the simple ON/OFF signal model?
The standard model needs an external ON/OFF power signal from your machine. The AGT package adds a programmable controller with built-in timers.
How many lubrication points can this pump feed?
It supports up to 60 lubrication points when paired with BU-M or BMUM progressive distributors. The actual count depends on divider section size.
Who builds this pump, and how do I get a quotation?
IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, builds and supports every unit. Email inquiry@isohitech.com for specifications and a quotation.
Contact the team with your pump model code.
