What a Grease Pump Hose Covers
A grease pump hose is the flexible link between the pump outlet and the point of use. It is the whip on a grease gun, the discharge line of a drum pump, and the coiled extension on a service-truck reel. This page covers dispensing hoses only. The fixed permanent lines that route grease to many points inside a centralized lubrication system are a different product family, and the figures here do not apply to them. Every number on this page belongs to a dispensing line that a technician pulls, coils, and handles during normal work.
The two classes below share one selection rule: the hose must be rated at or above the pump output it will see. A hose classed below the pump makes the weakest link a field failure.
Models and Specifications
Two construction classes cover the 3,000-10,000 PSI dispensing range. The thermoplastic class serves low to medium pressure gun work; the steel-reinforced class serves drum pumps and high-pressure stations.
| Specification | Thermoplastic | Steel-Reinforced |
|---|---|---|
| Working pressure | 3,000-5,000 PSI (207-345 bar) | 5,000-10,000 PSI (345-690 bar) |
| Inner tube | nylon or polyester | NBR |
| Reinforcement | 1-2 synthetic braids | 1-2 high-tensile steel wire braids |
| Cover | abrasion-resistant thermoplastic | oil and abrasion-resistant rubber |
| Inside diameter | 1/8″ (3.2 mm) to 1/4″ (6.4 mm) | 1/4″ (6.4 mm) to 3/8″ (10 mm) |
| Minimum bend radius | 13-25 mm | 25-38 mm |
| Temperature | -40°C to +100°C | -30°C to +121°C |
| Grease compatibility | NLGI 0-3 | NLGI 0-3 |
| Standard lengths | 12″, 18″, 24″ | 18″, 24″, 36″ |
The coiled extension version for hose reels and service trucks is supplied in 10-20 m lengths rated 4,000-5,800 PSI.
Thermoplastic or Steel-Reinforced
Thermoplastic hose builds its strength from synthetic braids over a nylon or polyester inner tube, wrapped in an abrasion-resistant thermoplastic cover. It stays light and flexible in the hand, which is why it dominates grease-gun whips and low-volume dispensing. Its pressure band runs 3,000-5,000 PSI (207-345 bar), with an inside diameter range of 1/8″ to 1/4″.
Steel-reinforced hose adds one or two high-tensile steel wire braids over an NBR inner tube, under an oil and abrasion-resistant rubber cover. It tolerates the repeated flexing and higher pressure of drum-pump stations, with a working band of 5,000-10,000 PSI (345-690 bar) and inside diameters from 1/4″ to 3/8″. If the pump can exceed 5,000 PSI, the steel-reinforced class is the correct hose.
Diameter, Bend Radius, and Cold Weather
Inside diameter decides flow and pumping effort. A 1/8″ (3.2 mm) bore suits low-volume gun work where the technician controls the pace. Drum-pump dispensing needs a 1/4″ (6.4 mm) bore as a minimum, so the pump does not fight its own discharge line; the steel-reinforced class extends to 3/8″ (10 mm) for higher-flow stations.
Minimum bend radius is the other half of the story. A kinked hose at the fitting is the number one field failure on dispensing lines. Keep thermoplastic hose above a 13-25 mm bend radius and steel-reinforced hose above 25-38 mm, and fit a 360 degree swivel end where the gun rotates constantly. Cold grease stiffens: NLGI 2-3 greases thicken in cold conditions, and a larger bore moves stiff grease more reliably, so cold-weather drum work favors the biggest practical bore.
Temperature coverage runs from -40°C to +100°C on thermoplastic hose and -30°C to +121°C on steel-reinforced hose, and both classes handle greases in the NLGI 0-3 range.
Matching a Hose to Your Pump
Start from the pump: an electric grease pump and a pneumatic drum pump place very different demands on a hose. The rule that runs through the whole grease pump range is simple: rate the hose at or above the pump rated output, and rate every other component in the line the same way.
The working pressure of the whole grease line equals its lowest rated component. Hose, coupler, and reel must each be rated at or above the pump maximum. A 10,000 PSI hose on a reel rated to 4,000 PSI is a 4,000 PSI line, whatever the hose says on its cover.
End Fittings, Lengths, and Replacement-on-Condition
End fittings come in two thread families. NPT is a tapered thread in 1/8″ or 1/4″, and BSPP is a parallel thread in G1/8″ or G1/4″. They seal differently and are not interchangeable, so match the thread on the pump outlet and the gun inlet before ordering. Zerk-style coupler ends cover standard fittings, and 360 degree swivel options keep the gun from twisting the hose behind it. Standard lengths run 12″, 18″, and 24″ on thermoplastic hose and 18″, 24″, and 36″ on steel-reinforced hose. The high-pressure hose and fitting page and the tubing and hose selection guide cover the surrounding choices for fixed lines and fittings.
There is no calendar replacement interval. Replace a hose on condition: cover cracking, weeping at the fittings, kinks, or soft spots. When a hose fails repeatedly at the same fitting, send the pump details and working pressure through the contact page so the replacement can be classed correctly.
Frequently Asked Questions
What is a grease pump hose?
A grease pump hose is a flexible dispensing line that carries grease from a pump to a gun, coupler, or lube point. It handles the moving, handheld part of the transfer that rigid tubing cannot.
How is a dispensing hose different from a centralized fixed line?
A dispensing hose serves pumps, guns, and reels on the movable side of the system. Fixed permanent lines of centralized systems are a different family; the grease pump guide covers that equipment.
Which working pressure should the hose have?
Rate the hose at or above the pump rated output. Thermoplastic covers 3,000-5,000 PSI and steel-reinforced covers 5,000-10,000 PSI.
Can I fit an NPT end into a BSPP port?
No. NPT is a tapered thread and BSPP is a parallel thread; they seal differently and are not interchangeable.
Which inside diameter suits drum-pump dispensing?
Use 1/4″ ID as the minimum for drum-pump dispensing. Cold NLGI 2-3 grease stiffens, so a larger bore moves it more reliably.
Why choose swivel ends?
A 360 degree swivel lets the gun rotate without twisting the hose. That prevents twist from walking the coupler off the fitting.
What is the coiled extension for?
It gives reels and service trucks a long reach that retracts out of the way. The coil is rated 4,000-5,800 PSI over 10-20 m lengths.
Does a cover add protection?
Yes, a spring cover takes rubbing and abrasion so the hose cover survives longer. It protects the outside without changing the pressure rating.
Is there a fixed replacement interval?
No, replace on condition: cover cracking, weeping fittings, kinks, or soft spots. Report the failure pattern through our quote contact page before reordering.
Who builds these hoses?
IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, builds and supports every unit. Email inquiry@isohitech.com for specifications and a quotation.
