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Sweeting Performance - Performance Brake Systems, Huntington Beach, CA (2026)

09/09/2026

1-3/4 Inch Master Cylinder for Bosch Hydro-Max® Brake System, Tall Reservoir (1.75" / 44.45 mm)

By the Sweeting Performance Team

While modern four-wheel disc brake commercial trucks rely on larger 2.00" bore master cylinders to push high fluid volume, earlier medium-duty trucks, buses, and step vans—mostly pre-2000 models running rear drum brakes or smaller caliper setups—were factory-equipped with a 1-3/4" (1.75" / 44.45 mm) bore master cylinder.

If you’ve tried sourcing an original factory 1-3/4" master cylinder recently, you’ve likely run into a dead end. Bosch no longer manufactures this smaller bore size, leaving dealer counters to flag these units as obsolete and no longer available.

To keep these working trucks and fleet vehicles on the road, Sweeting Performance offers a brand-new, high-quality aftermarket reproduction 1-3/4" tall-reservoir master cylinder. It serves as a direct drop-in replacement for the discontinued factory unit, featuring a high-capacity tall composite reservoir and standard inverted flare ports.

Sweeting Performance Part Number: HMMC17TR

Product Link: https://www.powerbrakeservice.net/hmmcdg175bs.html

Specifications:

* Bore Diameter: 1-3/4" (1.75" / 44.45 mm)
* Fluid Compatibility: DOT 3 Brake Fluid
* Reservoir Type: Attached, Tall-Profile, Dual-Chamber
* Differential Pressure Switch: No
* Primary Port: 9/16"-18 Inverted Flare
* Secondary Port: 1/2"-20 Inverted Flare
* Build Type: High-Quality Aftermarket Reproduction (Replaces Discontinued Bosch Units)

Technical Note on Availability:
Depending on current production stock, this master cylinder may ship with the differential pressure switch port fitted with a plug. If your unit arrives with a plugged port, it functions the same as a cylinder manufactured without the third port—maintaining a complete seal with zero impact on pedal feel or performance.

Understanding the Fluid Circuits:

There is only a mechanical connection between the Hydro-Max® booster and master cylinder; there is no fluid intermingling between the two units:

* Power Assist Circuit: Power steering fluid (or manufacturer-specified transmission fluid) flows from the engine-driven pump through the steering gear and Hydro-Max® booster body to supply hydraulic assist.
* Wheel Braking Circuit: The master cylinder operates on a separate circuit, pushing standard DOT 3 brake fluid through hard lines to the wheel cylinders or calipers.
* Fluid Type: Use only standard DOT 3 brake fluid.

Solving the Obsolete Factory Part Problem

Because original equipment manufacturers and Bosch have phased out production on 1-3/4" master cylinders, finding new-old-stock (NOS) or functional core replacements through traditional dealer networks is nearly impossible.

Our high-quality reproduction units give fleet managers, shop owners, and mechanics a brand-new, bolt-on solution engineered to match original factory dimensions and pressure output without having to retrofit modified brackets or hunt down used cores.

Common Applications:

* Pre-2000 Medium-Duty Commercial Trucks (Ford F-600, F-700, F-800 series; GM C60, C6500, Kodiak / TopKick 6-series)
* Ford L-Series Commercial Chassis
* B-Series Commercial and School Buses (Ford B-600/B-700, GM B-Series chassis)
* GM P-Series Step Vans and Delivery Vehicles
* International, Freightliner, and Motorhome/RV chassis utilizing 9/16"-18 primary and 1/2"-20 secondary inverted flare fittings requiring a 1-3/4" bore

Need Help Identifying Your Setup?

Power Brake Service and Sweeting Performance have been re-engineering, rebuilding, and supplying commercial hydraulic brake systems since 1950. Across three generations, we've handled pretty much every Hydro-Max® variation out there.

If you aren't sure whether your vehicle requires this 1-3/4" bore tall-reservoir unit:

1. Check your VIN, vehicle details, and look for raised casting numbers on the master cylinder body, as genuine Bosch units have the bore size cast onto the side.
2. Verify the thread sizes on your brake lines (9/16"-18 primary and 1/2"-20 secondary).
3. Email technical photos of your existing master cylinder, reservoir, and booster assembly to our tech team.

Ordering & Tech Support

* Product Link: https://www.powerbrakeservice.net/hmmcdg175bs.html
* Phone: (714) 330-5286
* Tech Email: [email protected]
* Website: www.powerbrakeservice.net

09/09/2026

1-3/4 Inch Master Cylinder for Bosch Hydro-Max® Brake System, Tall Reservoir w/ Differential Pressure Switch (1.75" / 44.45 mm)

By the Sweeting Performance Team

While modern four-wheel disc brake commercial vehicles rely on larger 2.00" bore master cylinders to push high fluid volume, earlier medium-duty trucks and buses—mostly pre-2000 models running rear drum brakes or smaller caliper setups—were factory-equipped with a 1-3/4" (1.75" / 44.45 mm) bore master cylinder.

If you’ve tried sourcing an original factory 1-3/4" master cylinder recently, you’ve likely run into a dead end. Bosch no longer manufactures this smaller bore size, leaving dealer counters to flag these units as completely obsolete and unavailable.

To keep these working trucks and buses on the road, Sweeting Performance offers a brand-new, high-quality aftermarket reproduction 1-3/4" tall-reservoir master cylinder. It serves as a direct drop-in replacement for the discontinued factory unit, featuring the standard tall composite reservoir, integrated differential pressure switch, and standard inverted flare ports.

Sweeting Performance Part Number: HMMC134TDPS

Product Link: https://www.powerbrakeservice.net/hymacywi1134.html

Specifications:

* Bore Diameter: 1-3/4" (1.75" / 44.45 mm)
* Fluid Compatibility: DOT 3 Brake Fluid
* Reservoir Type: Attached, Tall-Profile, Dual-Reservoir
* Differential Pressure Switch: Yes
* Primary Port: 9/16"-18 Inverted Flare
* Secondary Port: 1/2"-20 Inverted Flare
* Build Type: Aftermarket Reproduction (Replaces Discontinued Bosch Units)

Understanding the Fluid Circuits:

There is only a mechanical connection between the Hydro-Max® booster and master cylinder; there is no fluid intermingling between the two units:

* Power Assist Circuit: Power steering fluid (or manufacturer-specified ATF) flows from the engine-driven pump through the steering gear and Hydro-Max® booster body to supply hydraulic assist.
* Wheel Braking Circuit: The master cylinder operates on a completely separate circuit, pushing standard DOT 3 brake fluid through hard lines to the wheel cylinders or calipers.
* Fluid Type: This master cylinder uses standard glycol-based DOT 3 brake fluid.

What the Differential Pressure Switch Does:

Inside dual-circuit master cylinders, the primary and secondary hydraulic circuits operate independently. If a line blows or a wheel cylinder leaks on one circuit, pressure drops on that side. The integrated differential pressure switch detects that pressure imbalance immediately and grounds the circuit to trip your dash warning light—alerting drivers before pedal pressure is lost.

Common Applications:

* Pre-2000 Medium-Duty Commercial Trucks (Ford F-600, F-700, F-800 series; GM C60, C6500, Kodiak / TopKick 6-series)
* Ford L Series
* B-Series Commercial and School Buses (Ford B-600/B-700, GM B-Series chassis)
* Medium-duty drum-brake chassis across various truck, bus, and RV manufacturers
* Commercial platforms utilizing 9/16"-18 primary and 1/2"-20 secondary inverted flare fittings requiring a 1-3/4" bore, International, Freightliner, GM P-Series Stepvan

Need Help Identifying Your Setup?

Power Brake Service and Sweeting Performance have been re-engineering, rebuilding, and supplying commercial hydraulic brake systems since 1950. Across three generations, we've handled pretty much every Hydro-Max® variation out there.

If you aren't sure whether your vehicle requires this 1-3/4" bore tall-reservoir unit:

1. Check your VIN, vehicle details, and look for raised numbers on the master cylinder body as genuine Bosch units have the bore size cast onto the side.
2. Verify the thread sizes on your brake lines (9/16"-18 primary and 1/2"-20 secondary).
3. Email technical photos of your existing master cylinder, reservoir setup, and booster assembly to our tech team.

Ordering & Tech Support

* Product Link: https://www.powerbrakeservice.net/hymacywi1134.html
* Phone: (714) 330-5286
* Tech Email: [email protected]
* Website: www.powerbrakeservice.net

09/09/2026

1-3/4 Inch Master Cylinder for Bosch Hydro-Max® Brake System w/ Differential Pressure Switch, For Mineral Oil Brake Applications (1.75" / 44.45 mm)

By the Sweeting Performance Team

While Bosch Hydro-Max® master cylinders share a similar exterior housing across commercial trucks, buses, and heavy machinery, internal specifications vary significantly. Depending on the chassis, these master cylinders come in 1-3/4" (44.00 mm) or 2.00" (50.80 mm) bore sizes, feature short, tall, or remote reservoirs, and may or may not include an integrated differential pressure switch.

However, the most critical variation is the internal seal material. While the vast majority of Hydro-Max® master cylinders push standard DOT brake fluid through the braking circuit, a select group of heavy equipment and machinery utilize mineral oil in the wheel braking lines.

If you've tried looking for an original factory 1-3/4" mineral oil master cylinder lately, you already know the problem: they are long obsolete and nearly impossible to find. Because factory mineral oil master cylinders are now out of production from the factory, Sweeting Performance converts new aftermarket reproduction 1-3/4 inch master cylinders for use with mineral oil to continue offering new replacements: www.powerbrakeservice.net/sweeting-performance-1-75-inch-master-cylinder-for-bosch-hydro-max-brake-system-mineral-oil.html

Understanding the Fluid Circuits:

There is only a mechanical connection between the Hydro-Max® and master cylinder; there is no fluid intermingling between the booster and master cylinder.

* Power steering fluid (or manufacturer-specified transmission fluid) flows from the engine-driven pump to the steering gear, and then through the Hydro-Max® booster body to supply power assist.
* The master cylinder is on a separate hydraulic circuit, pushing fluid through the brake lines to the caliper pistons or wheel cylinders.
* Common Hydro-Max® master cylinders use DOT 3 brake fluid. If mineral oil or brake fluid were added to the wrong master cylinder type, the seals would swell and the fluid would leak out overnight. Sweeting Performance builds these specialized units with mineral-oil-compatible seals to work with vehicles utilizing mineral oil from the master cylinder to the front and rear brakes.

Specifications:

Bore Diameter: 1-3/4" (1.75" / 44.45 mm)
Fluid Compatibility: Mineral Oil ONLY
Differential Pressure Switch: Yes
Reservoir: Attached
Primary Line Port: 9/16"-18 Inverted Flare
Secondary Line Port: 1/2"-20 Inverted Flare
Material: Iron, Steel, Aluminum, Mineral-Oil Compatible Internal Seals, Plastic

What the Differential Pressure Switch Does:

Inside dual-circuit master cylinders, the primary and secondary hydraulic circuits operate independently. If a line blows or a seal leaks on one side, pressure drops on that circuit. The integrated differential pressure switch detects that imbalance immediately and grounds the circuit to trip your dash or control panel warning light—giving operators an alert before hydraulic pressure is lost.

Common Applications:

Mining Machinery and Underground Utility Vehicles
Agricultural and Forestry Equipment
Industrial Lift Trucks and Material Handling Machinery
Off-Highway Construction Equipment
Older or specialized commercial/industrial chassis requiring a 1-3/4" bore mineral oil brake setup

Need Help Identifying Your Setup?

Power Brake Service and Sweeting Performance have been re-engineering, rebuilding, and supplying commercial hydraulic brake systems since 1950. Across three generations, we've handled pretty much every Hydro-Max® variation out there.

If you aren't sure whether your machine needs this 1-3/4" mineral oil unit:

Check for raised casting numbers on the cylinder body, as genuine Bosch units have the bore size cast onto the side, or measure the piston dialmeter. Check the thread sizes on your brake lines (9/16"-18 primary and 1/2"-20 secondary). Email photos of your master cylinder, reservoir setup, part numbers, and vehicle model info to our tech staff.

Ordering & Tech Support
Product Link: https://www.powerbrakeservice.net/sweeting-performance-1-75-inch-master-cylinder-for-bosch-hydro-max-brake-system-mineral-oil.html
Phone: (714) 330-5286
Tech Email: [email protected]
Website: www.powerbrakeservice.net

09/02/2026

2 Inch Master Cylinder for Bosch Hydro-Max® Brake System, Remote Reservoir w/ Differential Pressure Switch (2.00" / 50.80 mm)

By the Sweeting Performance Team

When you're running four-wheel disc brakes on a heavy commercial chassis, a 2.00" bore master cylinder is necessary to push enough fluid volume for those larger multi-piston calipers. But on many specialized builds, tight overhead clearance or frame-mounting makes an attached reservoir impossible to reach or fit.

This version solves the packaging problem with a remote-reservoir adapter while adding an integrated differential pressure switch. That switch wires directly into your vehicle's dash warning system to alert you immediately if either the primary or secondary brake circuit experiences a pressure loss.

Sweeting Performance Part Number: HMMC200RRDS

Product Link: https://www.powerbrakeservice.net/hymacywirere.html

Specifications:

* Bore Diameter: 2.00" (50.80 mm)
* Fluid Compatibility: DOT 3 Brake Fluid
* Reservoir: Remote
* Differential Pressure Switch: Yes
* Primary Line Port: 9/16"-18 Inverted Flare
* Secondary Line Port: 1/2"-20 Inverted Flare
* Material: Iron, Steel, Aluminum, Rubber

What the Differential Pressure Switch Does

Inside dual-circuit master cylinders, the primary and secondary braking sections operate independently. If a brake line fails, a hose bursts, or a caliper seal leaks, hydraulic pressure drops on that side. The differential pressure switch senses the pressure imbalance between the two circuits and immediately trips the brake warning light on your dash—giving drivers an early alert that they are now only braking with their front or only braking with their rear brakes.

Why Use a Remote Reservoir?

It comes down to two practical shop issues: clearance and maintenance access.

1. Zero Overhead Clearance: Cab-over trucks, frame-mounted boosters beneath floorboards, and 90-degree reverse-linkage pedal boxes rarely have enough vertical room for a top-mounted reservoir.
2. Easy Maintenance Access: Checking brake fluid shouldn't require pulling floor plates or crawling under the truck. With a remote setup, the master cylinder stays tucked away on the frame, while the reservoir mounts high on the firewall or bulkhead for quick, clean checks and top-offs.

How the Remote Adapter Connects

* Adapter Plate: A low-profile adapter plate mounts to the top of the master cylinder body.
* Remote Reservoir: A dual-chamber reservoir mounts vertically in an accessible spot (usually the firewall).
* Supply Hoses: Two hoses connect the reservoir outlets to the adapter plate inlets to keep both circuits gravity-fed.

A Quick Reminder on Fluids

The Hydro-Max® booster and the master cylinder bolt together, but their fluid circuits are separate:

* Hydro-Max® Booster: Uses power steering fluid (or manufacturer recommend transmission fluid) from your engine's power steering pump.
* Master Cylinder & Reservoir Supply Lines: Uses standard DOT 3 brake fluid.

Never use petroleum-based fluids in the master cylinder or reservoir supply lines, as petroleum will cause the rubber to swell and fail rapidly.

Dealing with "Obsolete" Dealer Part Numbers

Because 2.00" remote master cylinders with pressure switches are used on everything from delivery vans and step vans to school buses, motorhomes, mining machinery, and airport ground support equipment (GSE), there are dozens of OEM part numbers for what is fundamentally the same core Bosch cylinder.

When dealers update their catalogs, older numbers often get flagged as "Obsolete" or "No Longer Available." The good news is that the core Bosch Hydro-Max® master cylinder is still actively put together and available through Sweeting Performance.

Common Applications:

* Frame-mounted Hydro-Max® brake setups with brake warning light circuits
* Mining and Heavy Industrial Equipment
* Cab-over trucks, step vans, and delivery vehicles
* Motorhomes and RV chassis
* Commercial buses and shuttle chassis
* Airport Ground Support Equipment (GSE) and tow tractors
* Medium-duty vehicles using 9/16"-18 primary and 1/2"-20 secondary hard lines with limited overhead space

Need Help Identifying Your Setup?

Power Brake Service and Sweeting Performance have been re-engineering, rebuilding, and supplying commercial hydraulic brake systems since 1950. Across three generations, we've handled pretty much every Hydro-Max® setup out there.

If you aren't sure if you need this 2.00" remote-reservoir unit with the differential pressure switch:

1. Check your VIN, vehicle details, and look for raised casting numbers on the cylinder body as genuine Bosch units will have the bore size cast onto the side.
2. Check the thread sizes on your hard lines (9/16"-18 and 1/2"-20) and confirm if your harness plugs into a pressure switch between the ports.
3. Send photos of your master cylinder, mounting location, and hose routing to our tech team.

Ordering & Tech Support

* Product Link: https://www.powerbrakeservice.net/hymacywirere.html
* Phone: (714) 330-5286
* Tech Email: [email protected]
* Website: www.powerbrakeservice.net

09/02/2026

2 Inch Master Cylinder for Bosch Hydro-Max® Brake System, Remote Reservoir (2.00" / 50.80 mm)

By the Sweeting Performance Team

When you're running four-wheel disc brakes on a heavy commercial chassis, you need a 2.00" bore master cylinder to move enough fluid for those larger multi-piston calipers. But on a lot of specialized builds, there just isn't room to mount a reservoir directly on top of the master cylinder—or if there is room, it's buried under a floorboard where you can't reach the cap to check or fill the fluid.

That’s where this remote-reservoir design comes in. It lets you mount the master cylinder down on the frame rail or inside a tight pedal box, while placing the reservoir up on the firewall where you can actually get to it.

Sweeting Performance Part Number: HMC200RR

Product Link: https://www.powerbrakeservice.net/sweeting-performance-master-cylinder-bosch-hydro-max-brake-system-2-inch-remote-reservoir-50-80-mm.html

Specifications:
* Bore Diameter: 2.00" (50.80 mm)
* Fluid Compatibility: DOT 3 Brake Fluid
* Reservoir: Remote
* Primary Line Port: 9/16"-18 Inverted Flare
* Secondary Line Port: 1/2"-20 Inverted Flare
* Material: Iron, Steel, Aluminum, Rubber

Why Use a Remote Reservoir?

It comes down to two practical shop issues: clearance and maintenance access.

1. Zero Overhead Clearance: Cab-over trucks, frame-mounted boosters beneath the floor, and 90-degree reverse-linkage pedal boxes often don't have enough vertical space for even a short reservoir.
2. Easy Maintenance Access: Checking brake fluid shouldn't require pulling floor panels or crawling under the truck. With a remote setup, the master cylinder stays tucked away on the frame, while the reservoir mounts high on the firewall or bulkhead for easy checks and top-offs.

How the Remote Adapter Connects

* Adapter Plate: A low-profile adapter plate mounts directly to the top ports of the master cylinder body.
* Remote Reservoir: A dual-chamber reservoir mounts vertically in an accessible spot (usually the firewall).
* Supply Hoses: Two fluid-rated hoses connect the reservoir outlets to the master cylinder adapter plate inlets to keep both circuits gravity-fed.

A Quick Reminder on Fluids

The Hydro-Max® booster and the master cylinder bolt together, but their fluid circuits are completely separate:

* Hydro-Max® Booster: Uses power steering fluid (or ATF) from your engine's power steering pump.
* Master Cylinder & Remote Lines: Uses standard DOT 3 brake fluid.

Never use petroleum-based fluids in the master cylinder or remote supply lines as they will cause the rubber to swell and fail rapidly.

Dealing with "Obsolete" Dealer Part Numbers

Because 2.00" remote master cylinders are used on everything from delivery vans and step vans to school buses, motorhomes, and airport ground support equipment (GSE), there are dozens of OEM part numbers for what is fundamentally the same core Bosch cylinder.

When dealers update their catalogs, older numbers often get flagged as "Obsolete" or "No Longer Available." The good news is that the core Bosch Hydro-Max® master cylinder is still actively put together and available through Sweeting Performance.

Common Applications:

* Frame-mounted Hydro-Max® brake setups (under-floor / chassis mount)
* Mining Equipment
* Cab-over trucks, step vans, and delivery vehicles
* Motorhomes
* Commercial buses and shuttle chassis
* Airport Ground Support Equipment (GSE) and tow tractors
* Medium-duty vehicles using 9/16"-18 primary and 1/2"-20 secondary hard lines with limited overhead space

Need Help Identifying Your Setup?

Power Brake Service and Sweeting Performance have been re-engineering, rebuilding, and supplying commercial hydraulic brake systems since 1950. Across three generations, we've handled pretty much every Hydro-Max® setup out there.

If you aren't sure if you need this 2.00" remote-reservoir unit:

1. Check your VIN, vehicle details, and look for raised casting numbers on the cylinder body as genuine Bosch units will have the bore size cast onto the side.
2. Check the thread sizes on your hard lines (9/16"-18 and 1/2"-20).
3. Send photos of your master cylinder, mounting location, and hose routing to our tech team.

Ordering & Tech Support

* Product Link: https://www.powerbrakeservice.net/sweeting-performance-master-cylinder-bosch-hydro-max-brake-system-2-inch-remote-reservoir-50-80-mm.html
* Phone: (714) 330-5286
* Tech Email: [email protected]
* Website: www.powerbrakeservice.net

09/01/2026

2 Inch Master Cylinder for Bosch Hydro-Max® Brake System, Short Reservoir (2.00 inch, 50.80 mm)

By the Sweeting Performance Engineering Staff

As commercial vehicle designs shifted toward four-wheel disc brake systems and higher Gross Vehicle Weight Ratings (GVWR), hydraulic fluid volume requirements grew significantly. vehicle manufacturers and Bosch moved toward a 2.00" (50.80 mm) bore master cylinder specifically to deliver the higher fluid displacement needed to drive heavy-duty multi-piston calipers. While standard firewall-mounted setups often accommodate tall reservoirs, tight engine bays and low-clearance chassis envelopes require a compact short-reservoir variant to prevent clearance issues.

Sweeting Performance supplies this original, genuine Bosch Hydro-Max® master cylinder built with a 2.00" bore, low-profile short composite reservoir, and standard inverted flare hydraulic outlets: https://www.powerbrakeservice.net/hymacywi2bos.html

Technical Specifications: Sweeting Performance Part # HMMC20SR

Bore Diameter: 2.00 Inch (50.80 mm)
Fluid Compatibility: DOT 3 Brake Fluid
Reservoir Type: Attached Low-Profile Dual-Chamber Composite Reservoir
Primary Outlet Port: 9/16"-18 Inverted Flare
Secondary Outlet Port: 1/2"-20 Inverted Flare
Materials: Cast Iron, Steel, Aluminum, Rubber

Packaging & Clearance: When to Specify the Short Reservoir

Determining whether your build needs a short or tall reservoir comes down to available vertical height and mounting location:

Tight Clearance Environments: Cab-over engine (COE) chassis, frame-mounted booster assemblies located beneath floorboards, and 90-degree reverse-linkage pedal boxes often have minimal vertical headroom. In these tight quarters, a tall reservoir will collide with sheet metal or floor framing, making this short-profile unit essential.

Fluid Capacity vs. Clearance: As disc brake pads wear down on multi-piston calipers, fluid level inside the reservoir gradually drops. If your booster and master cylinder are mounted on a standard firewall with unrestricted hood clearance, upgrading to a tall reservoir provides greater reserve capacity between maintenance intervals. However, if space is limited, staying with this short-reservoir configuration ensures a proper fit without structural interference.

Due to availability, this part may ship with a differential pressure switch port and a plug, it will operate the same as one without a third port.

Dual Hydraulic Circuits & Fluid Separation

While the Hydro-Max® booster and the master cylinder mount together on the firewall, their operation relies on two isolated hydraulic systems connected purely by a mechanical pushrod:

* Power Assist Hydraulic Circuit: Power steering fluid (or manufacturer-specified ATF) flows from the engine-driven pump through the steering gear and Hydro-Max® booster body to supply hydraulic assist. Fluid stays contained inside the booster.
* Wheel Braking Circuit: The master cylinder operates on a completely separate circuit, displacing fluid through the hard lines to the front and rear wheel caliper pistons or wheel cylinders.
* Fluid Type: This master cylinder uses standard DOT 3 brake fluid.

Overcoming Discontinued & "Obsolete" OEM Numbers

Because this specific 2.00" tall-reservoir master cylinder is utilized across a wide spectrum of platforms—including Ford, General Motors, Navistar/International, Freightliner, Workhorse, Blue Bird, Thomas Built, and various RV and GSE chassis—dozens of individual OEM part numbers exist for what is mechanically the same core assembly.

Original equipment manufacturers frequently update part numbers for minor production changes, such as altered casting or fluid reservoir designs that have no effect on fitment or operation. When a dealership parts system marks a specific part number as "Obsolete" or "No Longer Available (NLA)," it rarely means the physical master cylinder is out of production. The underlying Bosch Hydro-Max® part remains actively produced and fully available through Sweeting Performance.

Common Fleet & Commercial Applications
(Ideal for low-clearance commercial chassis, specialized machinery, and custom body builds)

Cab-Over Medium-Duty Trucks & Delivery Vans
Frame-Mounted Hydro-Max® Assemblies with Reverse Linkages
Commercial Buses, Shuttle Vans, and Step Vans
Ground Support Equipment (GSE) and Airport Service Tow Tractors
Medium-duty platforms utilizing standard 9/16"-18 primary and 1/2"-20 secondary line fittings

Identification & Technical Support

Power Brake Service and Sweeting Performance have been re-engineering, rebuilding, and distributing heavy-duty commercial hydraulic brake components since 1950. Backed by over seven decades of technical expertise across three generations, we can verify exact component replacements even when dealer lookup systems fail.

If you need to verify whether your application requires this 2.00" bore short-reservoir unit with 9/16"-18 and 1/2"-20 outlets:

1. Locate your VIN, vehicle year, make, model, and GVWR. Check the master cylinder body for raised numbers, as genuine Bosch units have the bore size cast into the side of the housing.
2. Check and record the fitting sizes on your existing hard lines.
3. Email clear photos of your current master cylinder, reservoir profile, and booster mounting setup directly to our technical team for confirmation.

Sweeting Performance is your go-to source for original replacement components and custom accessory parts for Bosch Hydro-Max® brake systems.

Ordering Information

Product Link: https://www.powerbrakeservice.net/hymacywi2bos.html
Phone Support: (714) 330-5286
Technical Email: [email protected]
Main Website: www.powerbrakeservice.net

09/01/2026

2 Inch Master Cylinder for Bosch Hydro-Max® Brake System, Short Reservoir with Differential Pressure Switch (2.00 inch, 50.80 mm)

By the Sweeting Performance Engineering Staff

As commercial chassis moved toward four-wheel disc brake architectures and higher Gross Vehicle Weight (GVW), Bosch introduced the 2.00" (50.80 mm) bore master cylinder to move the larger fluid volume required by heavy-duty multi-piston calipers. While tall-reservoir units became the standard for conventional firewall-mounted setups, this short-reservoir variant may be needed in applications with tight space constraints like vertical clearance limitations.

Sweeting Performance supplies this genuine, unaltered original Bosch Hydro-Max® master cylinder configured with a 2.00" bore, short composite reservoir, integrated differential pressure switch, and standard inverted flare ports: https://www.powerbrakeservice.net/hmmcgm2dss.html

Technical Specifications: Sweeting Performance Part # HMMCUN20SRDS

Specifications:
Bore Diameter: 2.00 Inch (50.80 mm)
Fluid Compatibility: DOT 3 Brake Fluid
Reservoir Type: Attached Short-Profile Dual-Chamber Composite Reservoir
Differential Pressure Switch: Yes
Primary Outlet Port: 9/16"-18 Inverted Flare
Secondary Outlet Port: 1/2"-20 Inverted Flare
Material: Iron, Steel, Aluminum, Rubber, Plastic

Packaging vs. Reservoir Capacity: When to Use the Short Reservoir

Selecting between a short and tall reservoir comes down to physical clearance and mounting location:

Packaging & Space Constraints: Cab-over engine (COE) chassis, frame-mounted booster assemblies beneath floorboards, and 90-degree reverse-linkage pedal boxes often have extremely limited vertical space above the master cylinder cap. In these tight enclosures, a tall reservoir will collide with the cab floor or firewall sheet metal, making this short-reservoir unit essential.

Reservoir Capacity Consideration: As brake pads wear down on high-volume multi-piston calipers, fluid level drops in the reservoir. If your booster and master cylinder are mounted on a standard firewall with ample hood clearance, and they have the same 9/16"-18 and 1/2"-20 port sizes, upgrading to the tall-reservoir version provides additional fluid reserve between service intervals. If you are limited on space, you may want to stay with the short reservoir.

Understanding the Fluid Circuits & Compatibility

While the Hydro-Max® booster and the master cylinder mount together, their operation relies on two isolated hydraulic systems connected purely by a mechanical pushrod:

Power Assist Hydraulic Circuit: Power steering fluid (or manufacturer-specified ATF) flows from the engine-driven pump through the steering gear and Hydro-Max® booster body to supply hydraulic assist. Fluid stays contained inside the booster.

Wheel Braking Circuit: The master cylinder operates on a completely separate circuit, displacing fluid through the hard lines to the front and rear wheel calipers or wheel cylinders.

Fluid Type: This master cylinder uses standard DOT 3 brake fluid. Never introduce petroleum-based hydraulic oils into this unit, as petroleum will destroy the internal rubber seals.

Navigating OEM "Obsolete" Part Numbers

Because short-reservoir 2.00" master cylinders are used across specialized commercial chassis, school buses, delivery vans, cab-overs, and ground support equipment (GSE), dozens of OEM part numbers exist for what is fundamentally the same core Bosch assembly.

When vehicle manufacturers update bracketry or part numbering systems, older numbers are frequently flagged as "Obsolete" or "No Longer Available (NLA)" by dealer counters. Despite these designations, the core Bosch Hydro-Max® master cylinder remains actively produced and available through Sweeting Performance.

Common Fleet & Chassis Applications
(Note: Fits a wide variety of commercial vehicles with low vertical clearance, including custom body builds and specialized equipment):

Cab-Over Medium-Duty Trucks & Delivery Vans
Frame-Mounted Hydro-Max® Brake Assemblies with Reverse Linkage
Commercial Buses, Step Vans, and RV Chassis
Ground Support Equipment (GSE) and Airport Service Vehicles
Medium-duty platforms utilizing 9/16"-18 primary and 1/2"-20 secondary line fittings.

Identification & Technical Support

Power Brake Service and Sweeting Performance have been rebuilding, re-engineering, and supplying commercial hydraulic brake systems since 1950. With over seven decades of technical experience across three generations, we can identify exact replacements even when part numbers or OEM dealer lookup systems fail.

If you are unsure whether your vehicle requires this 2.00" bore, short-reservoir unit with 9/16"-18 and 1/2"-20 ports:

1. Confirm VIN, vehicle year, make, model, chassis weight rating, and check the cylinder casting for raised numbers as genuine Bosch master cylinders have the bore size cast into the side of the housing.
2. Verify thread sizes on your brake line fittings.
3. Email technical photos of your existing master cylinder, reservoir height, and booster assembly to our engineering team for direct confirmation.

Sweeting Performance is the Go-To Source for Genuine Replacement Components as well as Custom Accessory Parts for Bosch Hydro-Max® Brake Systems

Ordering Information
Product Link: https://www.powerbrakeservice.net/hmmcgm2dss.html
Phone Support: (714) 330-5286
Technical Email: [email protected]
Main Website: www.powerbrakeservice.net

Sweeting Performance - Performance Brake Systems

09/09/2026

09/09/2026

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