The Mercury 858075K01 and Quicksilver 858075Q01 OEM Power Trim, Tilt, and Steering Fluids are premium marine hydraulic fluids formulated for compatible Mercury and Mariner outboards, Mercury Racing performance engines, and MerCruiser sterndrive power trim and hydraulic power steering systems.
Developed for demanding marine operating conditions, these fluids provide dependable hydraulic pressure transfer, pump lubrication, corrosion protection, and resistance to foaming and oxidation. Their specialized formulation helps protect hydraulic pumps, trim cylinders, internal valves, and seals during repeated trim and tilt operation.
Whether you're maintaining a classic Mercury two-stroke, servicing a high-performance Mercury Racing outboard, or rebuilding a hydraulic trim pump, choosing the right hydraulic fluid is essential for reliable operation and long-term component life.
Mercury & Quicksilver OEM Part Numbers – 32 oz
| Brand | Part Number | Description |
|---|---|---|
| Mercury Marine | 858075K01 | Power Trim & Steering Fluid – 32 oz |
| Quicksilver | 858075Q01 | Power Trim & Steering Fluid – 32 oz |
These fluids are recommended for applicable systems specifying conventional power trim and steering fluid, including certain applications calling for Type F automatic transmission fluid.
Marine Hydraulic Fluid Technology & Performance
A power trim and tilt system uses an electric motor-driven hydraulic pump to move pressurized fluid through internal valves and cylinders. This hydraulic pressure raises, lowers, and supports the outboard or sterndrive.
The fluid must efficiently transmit hydraulic pressure, lubricate internal components, and protect seals from premature wear.
- Foam Resistance: Helps minimize hydraulic aeration that can cause noisy pumps, inconsistent trim movement, and delayed hydraulic response.
- Corrosion Protection: Helps protect hydraulic pumps, valves, and internal components against corrosion in marine environments.
- Oxidation Resistance: Helps maintain fluid stability during extended operation and repeated temperature changes.
- Component Lubrication: Protects hydraulic pump components, valves, and sealing surfaces from excessive friction and wear.
- Reliable Hydraulic Operation: Supports consistent trim movement and hydraulic pressure when used in properly maintained systems.
Mercury Outboard, Mercury Racing & MerCruiser Applications
Mercury 858075K01 and Quicksilver 858075Q01 are suitable for many conventional hydraulic power trim and tilt systems used on Mercury, Mariner, Mercury Racing, and MerCruiser equipment.
Common engine families with compatible trim systems include Mercury 2.0L, 2.4L, 2.5L, and 3.0L V6 two-stroke outboards, covering selected 135, 150, 175, 200, 225, 250, and 300 HP models.
Performance applications may include compatible Mercury XR2, XR4, XR6, Pro Max, 260, 280, and 300 Drag outboards, along with other Mercury Racing hydraulic trim installations.
Power Trim Fluid vs. Hydraulic Steering Fluid
Although these products are labeled Power Trim & Steering Fluid, not every marine steering system uses the same hydraulic fluid.
Traditional Mercury hydraulic power trim systems and certain conventional hydraulic power steering applications may specify Mercury 858075K01 or Quicksilver 858075Q01.
Some modern electrically assisted power steering systems require specialized synthetic hydraulic fluid, while many SeaStar-style hydraulic helm systems require dedicated hydraulic steering fluid.
How to Check & Add Mercury Power Trim Fluid
- Routine hydraulic fluid inspection is essential for reliable trim and tilt operation.
- Begin by checking the trim pump, reservoir, hydraulic cylinders, hoses, and fittings for leaks or damage.
- Clean the reservoir filler area before removing the fill plug. Contamination from dirt or moisture can damage internal hydraulic components.
- Position and securely support the engine according to the service manual. Many conventional Mercury trim systems require checking the fluid with the engine fully tilted upward, although procedures vary by model.
- Check the reservoir level and slowly add the specified Mercury or Quicksilver fluid as necessary. Avoid overfilling.
- Reinstall the filler plug, operate the trim system through the recommended cycling procedure, and recheck fluid level and operation.
Safety: Never work beneath an unsupported outboard. Use the mechanical tilt support and additional suitable support when servicing the hydraulic system.
Troubleshooting Common Mercury Power Trim Problems
Slow or Jerky Trim Movement: May indicate low fluid, trapped air, restrictions, or worn hydraulic pump components.
Noisy Trim Pump: Often associated with hydraulic fluid aeration, cavitation, low fluid levels, or internal wear.
Engine Slowly Trims Down: May result from worn cylinder seals, leaking hydraulic valves, or internal pressure loss.
Milky or Cloudy Hydraulic Fluid: Can indicate water contamination requiring inspection and corrective service.
Trim Motor Runs but Engine Doesn't Move: Check fluid level, manual release valve, pump operation, and internal hydraulic valves.
Trim Motor Doesn't Run: Inspect battery voltage, trim switches, relays, wiring, electrical connections, and the pump motor.
Adding hydraulic fluid will not correct worn seals, defective valves, electrical failures, or a damaged hydraulic pump.
Buckshot Racing #77 Technical Maintenance Tips
Use the Correct Fluid: Power trim, hydraulic helm steering, and electrically assisted steering systems may require different fluid formulations.
Prevent Contamination: Always use clean filling equipment and protect the hydraulic reservoir from water, dirt, and debris.
Inspect for Leaks: A trim system that repeatedly requires fluid usually has a leak that should be identified and repaired.
Monitor Fluid Condition: Foamy, milky, or discolored fluid may indicate aeration, moisture intrusion, or internal component problems.
Follow Factory Procedures: Proper filling position, fluid level, bleeding methods, and service requirements vary between Mercury trim systems.
For high-performance Mercury Racing outboards, reliable hydraulic trim response is particularly important because engine trim angle directly influences boat handling, acceleration, and running attitude.