Ultraflex UP20F / UP25F / UP28F Front Mount Hydraulic Steering Helm

The Ultraflex UP20F, UP25F and UP28F are five-piston, front-mount hydraulic steering helm pumps for compatible marine hydraulic steering systems. Choose the UP20F 43180Y with 20cc/rev displacement, the UP25F 42462D with 25cc/rev displacement or the UP28F 42459R with 28cc/rev displacement. All three models have a built-in lock valve, an integral 70-bar / 1000psi relief valve, a standard 19mm / 3/4in tapered stainless-steel steering-wheel shaft and adjustable 90° fittings for 3/8in hydraulic hose.

Product Identification

• Brand: Ultraflex
• Product range: UP front-mount hydraulic helms
• Product category: Marine hydraulic steering helm pump
• Pump type: Manual hydraulic steering helm
• Available models: UP20F / UP25F / UP28F
• Manufacturer part numbers: 43180Y / 42462D / 42459R
• UP20F part number: 43180Y
• UP25F part number: 42462D
• UP28F part number: 42459R
• Mounting type: Front mount
• Pump design: Five-piston hydraulic helm
• Available displacement: 20cc, 25cc or 28cc per steering-wheel revolution
• Relief-valve setting: 70 bar / 1000psi
• Steering-wheel shaft: Stainless steel
• Wheel-shaft fitting: Standard 19mm / 3/4in taper
• Hose fittings: Adjustable 90° fittings for 3/8in hydraulic hose
• Application: Compatible marine hydraulic steering systems

What Are These Hydraulic Helm Pumps Used For?

The Ultraflex UP20F, UP25F and UP28F convert steering-wheel rotation into hydraulic fluid flow. When connected to a compatible hydraulic cylinder through the correct steering hoses, turning the wheel moves the cylinder and controls the boat's rudder, outboard engine or sterndrive steering mechanism.

They can be used for:

• New marine hydraulic steering installations
• Replacement of a compatible front-mount hydraulic helm
• Single-station hydraulic steering systems
• Compatible multi-station systems designed in accordance with Ultraflex installation data
• Suitable outboard, inboard and sterndrive steering configurations

The helm pump is only one component of the steering system. It must be correctly matched to the cylinder volume, engine or rudder arrangement, hydraulic hoses and required number of steering-wheel turns.

Engine horsepower capacity is determined by the complete hydraulic steering system rather than the helm pump alone.

What Is Included?

The selected Ultraflex hydraulic helm pump is supplied with:

• Selected UP20F, UP25F or UP28F front-mount helm pump
• Built-in lock valve
• Integral over-pressure relief valve
• Standard 3/4in tapered stainless-steel steering-wheel shaft
• Adjustable 90° fittings for 3/8in hydraulic hose

Not included:

• Steering wheel
• Hydraulic steering cylinder
• Hydraulic steering hoses
• Hydraulic steering oil
• Filling or bleeding kit
• Additional steering-station connection kit
• Optional dashboard-positioning flange
• Optional tilt mechanism
• Engine, rudder or steering linkage components

Which Hydraulic Steering Systems Are Compatible?

Compatibility depends on the selected helm model, hydraulic-cylinder volume, boat configuration, steering load and complete system design.

UP20F compatibility:

Ultraflex specifies the UP20F for use only with the following cylinders:

• Ultraflex UC95-OBF front-mount outboard cylinder
• Ultraflex UC68-OBS side-mount outboard cylinder
• Ultraflex UC69-I inboard cylinder

Do not combine the UP20F with a different cylinder unless that combination is expressly approved by Ultraflex.

UP25F and UP28F compatibility:

The UP25F and UP28F must be matched to a compatible Ultraflex cylinder using the current steering-system selection data. Before ordering, confirm:

• Cylinder model and internal volume
• Number and type of engines
• Total engine horsepower
• Inboard, outboard or sterndrive configuration
• Required turns from lock to lock
• Single- or multi-station installation
• Hose type, diameter and working-pressure rating
• Maximum steering-wheel diameter
• Available dashboard and behind-panel clearance

Do not select a helm pump solely from engine horsepower. The cylinder, helm displacement, hoses, fittings and engine or rudder arrangement must be approved as one complete steering system.

Which Model Should I Choose?

• UP20F / 43180Y: 20cc/rev displacement, 3.6kg weight and maximum 508mm / 20in steering-wheel diameter. Restricted to UC95-OBF, UC68-OBS and UC69-I cylinders.
• UP25F / 42462D: 25cc/rev displacement, 5kg weight and maximum 710mm / 28in steering-wheel diameter. Provides an intermediate displacement between the UP20F and UP28F.
• UP28F / 42459R: 28cc/rev displacement, 5kg weight and maximum 710mm / 28in steering-wheel diameter. Moves more hydraulic fluid per wheel revolution than the UP20F or UP25F.

For the same cylinder volume and steering configuration, a higher-displacement helm normally produces fewer steering-wheel turns from lock to lock but requires greater steering effort. A lower-displacement helm normally produces more turns with lower effort.

The required number of turns can be estimated from cylinder volume divided by helm displacement, but the approved Ultraflex system specification remains the controlling selection requirement.

Hydraulic Specifications and Fitment

UP20F / 43180Y

• Mounting: Front mount
• Displacement per revolution: 20cc / 1.2cu.in
• Number of pistons: Five
• Relief-valve setting: 70 bar / 1000psi
• Maximum steering-wheel diameter: 508mm / 20in
• Weight: 3.6kg / 8lb
• Wheel-shaft taper: 19mm / 3/4in
• Hose fitting size: 3/8in
• Housing: Corrosion-resistant composite
• Approved cylinder models: UC95-OBF, UC68-OBS and UC69-I only

UP25F / 42462D

• Mounting: Front mount
• Displacement per revolution: 25cc / 1.5cu.in
• Number of pistons: Five
• Relief-valve setting: 70 bar / 1000psi
• Maximum steering-wheel diameter: 710mm / 28in
• Weight: 5kg / 11lb
• Wheel-shaft taper: 19mm / 3/4in
• Hose fitting size: 3/8in
• Piston race: Ball bearing
• Rotor material: Cast iron

UP28F / 42459R

• Mounting: Front mount
• Displacement per revolution: 28cc / 1.7cu.in
• Number of pistons: Five
• Relief-valve setting: 70 bar / 1000psi
• Maximum steering-wheel diameter: 710mm / 28in
• Weight: 5kg / 11lb
• Wheel-shaft taper: 19mm / 3/4in
• Hose fitting size: 3/8in
• Piston race: Ball bearing
• Rotor material: Cast iron

The UP20F uses a different housing and dashboard arrangement from the UP25F and UP28F. Do not assume that the helm pumps share the same dashboard cut-out, mounting-hole pattern or optional flange.

Construction and Design

Features common to all three models include:

• Five-piston hydraulic pumping mechanism
• Built-in lock valve for positive rudder lock
• Integral relief valve for over-pressure protection
• Standard 3/4in tapered stainless-steel shaft
• Accessible lock valve and shaft seal for servicing
• Adjustable 90° hydraulic-hose fittings
• Front-mount dashboard installation
• Construction intended for marine hydraulic steering systems

The built-in lock valve provides positive hydraulic rudder lock and helps prevent steering loads from hydraulically driving the steering wheel backwards.

The integral relief valve is set to 70 bar / 1000psi to protect the steering system against excessive hydraulic pressure. It does not remove the requirement for correctly rated hoses, fittings and cylinders.

The UP20F uses a corrosion-resistant composite housing. The UP25F and UP28F use a ball-bearing piston race and cast-iron rotor for durability within the hydraulic pumping mechanism.

Optional Mounting Accessories

Optional mounting accessories are sold separately.

For the UP20F:

• X74 square flange: Allows the UP20F to be positioned partially within the dashboard for an intermediate mounting position

For the UP25F and UP28F:

• X64 square flange: Intermediate dashboard-position mounting
• X57 round flange: Intermediate dashboard-position mounting
• X72 tilt mechanism: Provides a 60° adjustment range with five locking positions

Confirm that the selected accessory is compatible with the exact pump model before ordering. The accessory does not change the hydraulic displacement or cylinder compatibility of the helm.

Steering-Wheel Compatibility

All three pumps use a standard 19mm / 3/4in tapered stainless-steel steering-wheel shaft.

Before choosing a steering wheel, confirm:

• The wheel has a standard 3/4in tapered hub
• The wheel diameter does not exceed the selected helm's maximum
• The wheel and hub seat correctly on the shaft taper
• The correct shaft key and retaining hardware are used
• The wheel can rotate through the complete steering range without contacting instruments, controls or the dashboard

Maximum stated wheel diameters are:

• UP20F: 508mm / 20in
• UP25F: 710mm / 28in
• UP28F: 710mm / 28in

A steering wheel is not included with any of the three helm pumps.

Standards and Certification

Ultraflex conformity documentation for the UP20, UP25 and UP28 hydraulic helm families references:

• Recreational Craft Directive 2013/53/EU
• EN ISO 10592:2017
• ABYC P21
• IMCI CE type approval
• NMMA type acceptance

Certification of the helm pump does not certify an incorrectly selected or installed steering system. The cylinder, hoses, fittings, hydraulic fluid, steering wheel and installation must comply with the applicable Ultraflex instructions and marine regulations.

Installation and Use

Before installation:

• Confirm the exact selected model and part number
• Verify the pump-to-cylinder compatibility
• Check the required helm displacement and turns from lock to lock
• Check dashboard cut-out and mounting-hole dimensions against the selected model's drawing
• Confirm sufficient clearance behind and in front of the dashboard
• Confirm that the dashboard is rigid enough to support the helm and steering loads
• Check that the steering wheel remains within the helm's maximum diameter
• Confirm that all hoses and fittings have the required pressure rating

Do not use the mounting template or dashboard cut-out dimensions from a different Ultraflex helm model.

Connect the hydraulic hoses to the correct pump ports using the supplied 90° adjustable fittings. Hose routing must avoid:

• Tight bends
• Abrasion points
• Hot engine components
• Moving machinery
• Areas where the hoses can be crushed or pulled
• Unnecessary high points that may retain air

Fill and bleed the system using the hydraulic fluid and procedure specified by Ultraflex. Air remaining in the system can cause excessive steering-wheel movement, delayed steering response and incomplete cylinder travel.

After installation and bleeding, check that:

• The steering wheel turns smoothly in both directions
• The cylinder reaches its complete permitted travel
• The system reaches both steering limits without binding
• There is no excessive steering-wheel free movement
• The helm remains securely fixed to the dashboard
• The steering wheel remains securely seated on the shaft
• No oil leaks are present at the helm, fittings, hoses or cylinder
• Hydraulic hoses do not contact moving or hot components
• The lock valve provides consistent steering position
• The fluid level remains correct after repeated operation

Marine steering is a safety-critical system. Leaks, damaged hoses, incorrect cylinder selection, persistent air or abnormal helm movement must be corrected before the boat is used.

Key Features

• Combined choice of three Ultraflex front-mount hydraulic helms
• UP20F manufacturer part number 43180Y
• UP25F manufacturer part number 42462D
• UP28F manufacturer part number 42459R
• 20cc, 25cc or 28cc displacement per wheel revolution
• Five-piston hydraulic design
• Built-in lock valve for positive rudder lock
• Integral 70-bar / 1000psi relief valve
• Standard 19mm / 3/4in tapered stainless-steel shaft
• Adjustable 90° fittings for 3/8in hydraulic hose
• Accessible lock valve and shaft seal
• UP20F corrosion-resistant composite housing
• UP25F and UP28F ball-bearing piston race
• UP25F and UP28F cast-iron rotor
• UP20F maximum wheel diameter of 508mm / 20in
• UP25F and UP28F maximum wheel diameter of 710mm / 28in
• UP20F weight of 3.6kg / 8lb
• UP25F and UP28F weight of 5kg / 11lb
• Optional dashboard-positioning accessories available separately
• Steering wheel, cylinder, hoses and hydraulic oil supplied separately
• Complete steering-system compatibility must be confirmed before installation