MROStop stocks a complete filtration range across three product families —
hydraulic filters and fluid conditioning equipment for protecting hydraulic systems and maintaining fluid cleanliness,
engine and truck components covering air, oil, fuel, coolant, and DEF filtration for heavy-duty vehicles and equipment, and
gas and steam filters for process and utility applications. All categories include elements, housings, parts, and repair kits.
Use the sections below to browse by product family, or
call our team for help with element cross-reference, housing selection, or fluid cleanliness requirements.
Common Questions
Frequently Asked Questions
What is the difference between a return filter, a pressure filter, and a suction filter?
The three filter locations correspond to different points in the hydraulic circuit. A
suction filter is mounted at the pump inlet and protects the pump from large particles in the reservoir — it must have minimal pressure drop to avoid cavitating the pump. A
pressure filter is installed downstream of the pump at system working pressure and provides fine filtration to protect sensitive downstream components like servo valves. A
return filter is mounted on the return line before the reservoir and captures contamination generated by actuators and valves during operation. Most systems include at minimum a suction strainer and a return filter; servo and proportional valve systems also require a pressure filter.
What micron rating do I need for my hydraulic system?
The required filtration rating depends on the most sensitive component in your hydraulic system. As a general guide:
standard hydraulic systems with directional control valves typically require ISO 4406 cleanliness code 18/16/13, achievable with 10–25 micron return filtration.
Proportional valve systems require approximately 17/15/12, needing 6–10 micron filtration.
Servo valve systems require 16/14/11 or better, requiring 3–6 micron filtration with pressure-side elements. Contact our team with your system type and we can recommend the correct element rating and cleanliness monitoring approach.
What is a duplex filter and when is one required?
A duplex filter contains two filter bowls with a changeover valve between them. While one bowl is in service, the other is on standby. When the in-service element reaches its bypass pressure (indicating it is loaded with contamination), the operator switches to the standby bowl and replaces the loaded element — all without interrupting flow to the system. Duplex filters are used on systems that cannot tolerate a shutdown for filter element replacement, such as continuously operating hydraulic presses, injection moulding machines, and process equipment.
What causes water contamination in hydraulic fluid and how is it removed?
Water enters hydraulic systems through condensation in the reservoir vent, ingression through worn cylinder rod seals, and cooler leaks. Even small amounts of water accelerate oxidation of the hydraulic fluid, promote bacterial growth, cause additive dropout, and dramatically reduce the fatigue life of metal surfaces. Water contamination is removed using
vacuum dehydration units, which heat the fluid under vacuum to vaporise dissolved and free water without damaging the fluid additives. Desiccant reservoir breathers also help by preventing atmospheric moisture from entering through the vent. Both products are available in our fluid conditioning range.
Why is DEF filtration important and what contamination does it address?
Diesel Exhaust Fluid is a precisely formulated 32.5% urea solution that is sensitive to contamination and dilution. Particulate contamination from bulk storage tanks and transfer equipment causes blockages in SCR injectors, which triggers engine derate events and requires expensive injector replacement. Metallic contamination — particularly from brass or copper fittings and tanks — degrades the urea solution and can damage the SCR catalyst. Inline DEF filter elements remove particulate to protect the SCR system, and using DEF-compatible materials throughout the transfer equipment prevents chemical contamination. Our DEF range covers filters, housings, pumps, hoses, and nozzles, all using DEF-compatible materials.
Can MROStop cross-reference hydraulic filter elements to other brands?
Yes. Our team can cross-reference hydraulic filter elements across the major brands including Donaldson, Parker, Hydac, Pall, Argo Hytos, Schroeder, and Baldwin. If you have an existing element part number and want to find an equivalent, contact us with the part number and housing type and we will identify the correct replacement. Donaldson also provides a published cross-reference for their P-Series and FHP-Series elements, which we can access on your behalf.
Does MROStop support account-based purchasing for maintenance and fleet teams?
Yes. MROStop runs on OroCommerce, which supports company accounts with multiple users, purchasing approval workflows, saved shopping lists for recurring filter orders, cost-centre tracking, and order history export. Contact our team to configure an account structure that fits how your maintenance or fleet department manages procurement.
