Meritor Q Plus LX500 Cam Brake

Quick Facts

Manufacturer: Meritor, a Cummins company
Product Family: Q Plus
Product Model: LX500
Common Product Marking: Q+ LX500
Product Type: Extended-lubrication S-cam drum-brake package
Brake Category: Heavy-duty pneumatic foundation brake
Primary Positions: Steer and drive axles
Primary Applications: Line-haul trucks, vocational vehicles, buses, and other heavy commercial vehicles
Actuation: Air brake chamber, automatic slack adjuster, camshaft, and S-cam
Adjustment: Factory-installed Meritor automatic slack adjuster
Lubrication Feature: Extended lubrication intervals for the camshaft and automatic slack adjuster
Line-Haul Lubrication Interval: Up to three years or 500,000 miles, whichever comes first, under specified operating conditions
Other-Application Lubrication Interval: One year regardless of mileage
Primary Benefit: Reduces scheduled lubrication requirements while retaining the familiar Q Plus drum-brake architecture
Current Brand Ownership: Meritor became part of Cummins in 2022, while Meritor-branded brake products continue to be supported

Overview

The Meritor Q Plus LX500 Cam Brake is an extended-lubrication version of the company’s Q Plus heavy-duty S-cam drum brake. It combines application-specific Q Plus foundation brakes with factory-installed Meritor automatic slack adjusters and an extended-lubrication package.

The LX500 was designed to reduce routine chassis-lubrication requirements without eliminating normal brake inspection and preventive maintenance. Seals, bushings, synthetic grease, and precision-machined components help retain lubricant while limiting the entry of water and contaminants.

For eligible on-highway line-haul applications, Meritor specifies that the LX500 camshaft and factory-installed automatic slack adjuster do not require periodic lubrication for three years or 500,000 miles, whichever occurs first. For other vehicle applications, the specified lubrication interval is one year regardless of mileage.

These intervals apply to properly identified LX500 packages under the conditions stated in Meritor’s service information. Brake linings, drums, chambers, springs, rollers, air lines, pushrod stroke, and other safety-related components still require regular inspection.

The LX500 should not be confused with the Q Plus MX500. The LX500 primarily adds an extended-lubrication package, while the MX500 combines LX500 components with an extended-maintenance friction package intended for specified on-highway line-haul applications.

Key Characteristics

Q Plus S-cam drum-brake architecture
Extended-lubrication cam-brake package
Factory-installed Meritor automatic slack adjusters
Special camshaft seals and bushings
Factory-installed synthetic lubricant
Plugged lubrication openings during the extended interval
Identification tag covering the chamber-bracket grease plug
Reduced scheduled lubrication requirements
Available for steer- and drive-axle applications
Multiple brake sizes and lining widths
Quick-change Q Plus brake shoes
Replaceable friction linings
Compatible with commercial-vehicle ABS
Suitable for line-haul and vocational vehicles
Established Meritor aftermarket support

Major Components

Q Plus brake spider
Brake shoes
Friction linings
Anchor pins
Anchor-pin bushings
Brake rollers
Roller retainers
Shoe return springs
Retaining springs
S-camshaft
Camshaft bushings
Extended-lubrication camshaft seals
Camshaft washers
Camshaft support bracket
Plugged lubrication opening
LX500 identification tag
Factory-installed synthetic grease
Meritor automatic slack adjuster
Threaded or welded clevis
Brake chamber
Brake chamber pushrod
Clevis pin
Brake drum
Dust shield when equipped
Mounting hardware
ABS wheel-speed sensor
ABS tone ring
Wheel hub
Wheel bearings and seals

How the Brake Component or System Works

When the driver applies the service brakes, compressed air enters the brake chamber. Air pressure moves the diaphragm and chamber pushrod.

The pushrod rotates the factory-installed automatic slack adjuster. The slack adjuster turns the camshaft, causing the S-shaped cam head to move the brake rollers and spread the shoes outward.

The friction linings press against the inside surface of the rotating brake drum. Friction converts the vehicle’s motion into heat, slowing or stopping the wheel.

When the brake is released, air leaves the chamber. Return springs pull the brake shoes away from the drum, and the mechanical components return to their released positions.

The automatic slack adjuster compensates for normal increases in shoe-to-drum clearance. It helps maintain the correct relationship between brake chamber stroke and camshaft movement.

The LX500 extended-lubrication components do not change the basic way the Q Plus brake creates stopping force. Instead, they protect the camshaft, bushings, and automatic slack adjuster so they can operate for longer periods before scheduled lubrication is required.

Position and Function Within the Brake System

The Q Plus LX500 is located at the wheel end and functions as the vehicle’s foundation brake. Depending on its configuration, it can be installed on steer or drive axles.

The complete braking sequence involves:

The driver applying the brake pedal
The foot valve creating an air-pressure signal
Relay or ABS valves directing air to the brake chambers
Brake chambers extending their pushrods
Automatic slack adjusters rotating the camshafts
S-cams spreading the brake shoes
Friction linings contacting the drums
Tires transferring braking force to the road

On drive axles equipped with spring-brake chambers, the same foundation-brake components also provide parking and emergency-brake functions.

The LX500 package does not independently regulate air pressure or prevent wheel lockup. Those functions are performed by the vehicle’s pneumatic controls, ABS, stability system, and driver inputs.

Common Specifications

Brake Type: Pneumatically operated S-cam drum brake
Product Family: Meritor Q Plus
Package: LX500 extended-lubrication package
Steer-Axle Brake Sizes: 15-inch by 4-inch or 15-inch by 5-inch
Drive-Axle Brake Sizes: 16.5-inch by 7-inch or 16.5-inch by 8-inch
Additional Drive-Axle Configuration: 15-inch by 8⅝-inch for selected 19.5-inch wheel applications
Adjustment: Factory-installed Meritor automatic slack adjuster
Slack-Adjuster Clevis: Threaded or welded, depending on configuration
Line-Haul Lubrication Interval: Three years or 500,000 miles, whichever comes first
Other-Application Lubrication Interval: One year regardless of mileage
Lubricant: Meritor-approved synthetic grease specified in the service literature
Actuation: Pneumatic brake chamber
Foundation-Brake Position: Steer or drive axle
ABS Compatibility: Compatible with properly specified commercial-vehicle ABS
Friction Material: Application-specific
Brake Drum: Application-specific commercial brake drum

The specifications above describe established LX500 configurations documented by Meritor. The exact brake size, lining, chamber, camshaft, slack adjuster, drum, axle rating, and lubrication procedure must be confirmed for the individual vehicle.

Operating Specifications and Performance

The LX500 provides the braking characteristics of the Q Plus foundation brake while extending the lubrication interval for the camshaft and automatic slack adjuster.

Under Meritor’s documented service schedule, an eligible on-highway line-haul LX500 installation can operate for three years or 500,000 miles before scheduled lubrication, whichever comes first. Other applications use a one-year interval regardless of mileage.

These extended intervals do not apply universally to every component or operating condition. Fleets must continue inspecting:

Brake-lining thickness
Applied pushrod stroke
Brake-drum condition
Air chambers
Return springs
Brake rollers
Air hoses and fittings
Automatic slack-adjuster operation
Brake balance
ABS components

Severe operating conditions, contamination, component damage, pressure washing, flooding, or unusual wear may require service before the scheduled interval.

Braking performance depends on brake size, chamber size, effective slack-adjuster length, air pressure, friction material, drum condition, axle loading, and tire traction.

Braking Performance and System Integration

The LX500 must be matched to the vehicle’s complete braking system. Correct brake torque depends on the relationship among the chamber, slack adjuster, camshaft, shoes, friction material, and drum.

All brakes on the same axle should use compatible components and friction materials. Mismatched parts can cause unequal stopping force and temperature differences.

Brake imbalance may result from:

Different lining formulations
Unequal pushrod stroke
Incorrect slack-adjuster lengths
Different chamber sizes
Contaminated friction material
Oversized or damaged drums
Restricted camshaft movement
Air-pressure differences
Uneven axle loading
ABS or valve problems

The extended-lubrication feature does not correct pneumatic imbalance, worn friction components, or incorrect brake adjustment.

Air Supply, Controls, and Electronic Integration

The Q Plus LX500 relies on the vehicle’s compressed-air system. The air compressor, dryer, reservoirs, valves, lines, chambers, and controls must supply clean air at the required pressure.

The brake can operate with:

Truck and tractor air-brake systems
Service brake chambers
Spring-brake chambers
Relay valves
Quick-release valves
Spring-brake control valves
Antilock braking systems
Automatic traction control
Electronic stability control
Wheel-speed sensors

ABS monitors wheel speed and adjusts chamber pressure when wheel lockup is detected. It does not mechanically inspect, lubricate, or adjust the LX500 foundation brake.

Stability-control systems may selectively apply individual brakes, but their performance depends on properly maintained foundation brakes, tires, sensors, valves, and electronic controls.

Installation, Adjustment, and Brake Balance

The LX500 must be installed using the brake size, camshaft, chamber, slack adjuster, clevis, and wheel-end components approved for the axle.

Important installation checks include:

Confirming the brake is an LX500 package
Verifying the brake size
Matching the axle and spider
Identifying camshaft rotation
Checking camshaft length and spline
Installing the correct brake shoes
Matching the friction material
Installing rollers and springs correctly
Confirming slack-adjuster length
Setting the clevis position
Verifying brake chamber size
Measuring applied pushrod stroke
Inspecting the drum
Checking wheel-end clearance
Testing automatic slack-adjuster operation
Confirming balanced braking across the axle

The factory-installed automatic slack adjuster should not be repeatedly adjusted manually to compensate for an unresolved problem.

Meritor specifies that the LX500 brake and slack adjuster should not be lubricated before the designated interval. The identification tag and grease plugs should remain in place during the extended-lubrication period.

Foundation Brake, Axle, and Wheel-End Compatibility

The Q Plus LX500 was offered in several steer- and drive-axle configurations.

Documented steer-axle packages include:

15-inch by 4-inch cam brake
15-inch by 5-inch cam brake

Documented drive-axle packages include:

16.5-inch by 7-inch cam brake
16.5-inch by 8-inch cam brake
15-inch by 8⅝-inch cam brake for selected 19.5-inch wheel applications

Compatibility depends on:

Axle manufacturer
Axle model
Axle rating
Brake spider
Brake diameter
Lining width
Camshaft length
Camshaft rotation
Camshaft spline
Automatic slack-adjuster length
Brake chamber
Brake drum
Hub
Wheel size
ABS equipment
Vehicle brake certification

An LX500 package should not be created by adding plugs or removing grease fittings from a standard Q Plus brake. The proper seals, bushings, lubricant, machined components, and factory-installed automatic slack adjuster are part of the complete package.

Common Applications

On-highway line-haul tractors
Regional-haul tractors
Heavy-duty straight trucks
Delivery trucks
Vocational trucks
Dump trucks
Concrete mixers
Refuse vehicles
Construction trucks
Utility trucks
Tank trucks
Municipal vehicles
School buses
Transit buses
Motorcoaches
Vehicles using 19.5-inch wheel applications
Commercial vehicles seeking extended lubrication intervals

Vehicle and Brake-System Compatibility

The LX500 must be matched to the vehicle’s axle, brake, wheel-end, and operating application.

Compatibility should be verified using:

Vehicle manufacturer
Vehicle identification number
Vehicle model and model year
Axle manufacturer
Axle model and serial number
Gross axle weight rating
LX500 identification tag
Brake diameter and width
Brake shoe number
Friction-lining code
Camshaft number
Slack-adjuster number
Clevis type
Brake chamber size
Drum number
Hub configuration
Wheel size
ABS configuration
Vehicle vocation

Similar vehicles may use standard Q Plus, LX500, MX500, or other foundation-brake packages. The model name of the truck alone does not confirm the installed brake.

Advantages

Extended camshaft lubrication interval
Extended automatic slack-adjuster lubrication interval
Reduced scheduled greasing requirements
Factory-installed automatic slack adjusters
Special seals help exclude contaminants
Synthetic grease retained within the assembly
Precision-machined components
Familiar Q Plus drum-brake operation
Multiple steer- and drive-axle configurations
Suitable for line-haul and vocational applications
Replaceable brake shoes and friction linings
Compatible with commercial-vehicle ABS
Broad Meritor parts support
Reduced routine maintenance downtime
Established heavy-duty service history

Limitations or Considerations

Extended lubrication does not eliminate brake inspection
Lubrication intervals depend on vehicle application
Non-line-haul applications use a shorter interval
Brake linings and drums still require routine inspection
Identification tags must remain in place
Grease plugs should not be removed prematurely
Standard Q Plus parts do not automatically create an LX500 package
Different LX500 configurations are not universally interchangeable
Brake drum removal is required for complete internal inspection
Drums and wheel-end components are heavy
Repeated braking can produce drum-brake fade
Contaminated friction material usually requires replacement
Pushrod stroke must still be measured
Automatic slack adjusters require functional inspections
Improper lubrication can damage seals or contaminate linings
Older installations may require additional parts-identification work

Driver and Operator Experience

A properly maintained LX500 should provide braking performance comparable to an appropriately specified Q Plus drum brake. The primary operational difference is the reduced frequency of scheduled lubrication for the camshaft and automatic slack adjuster.

Drivers are unlikely to notice the extended-lubrication components during normal operation. They should still monitor the vehicle for changes in brake response.

Drivers should report:

Increased stopping distance
Vehicle pulling during braking
Brake grabbing
Delayed brake release
Low-air warnings
ABS warning lamps
Burning odors
Wheel-end smoke
Grinding or scraping
Unusual air loss
Parking brakes that do not hold
Different wheel-end temperatures
Brake-stroke inspection failures

The extended-lubrication feature should never be interpreted as permission to ignore unusual brake behavior.

Maintenance and Ownership Notes

Preserve the LX500 identification tag
Do not lubricate before the specified interval
Leave grease plugs installed during the extended interval
Follow the correct line-haul or vocational schedule
Inspect brake-lining thickness
Measure applied pushrod stroke
Inspect brake drums
Measure drum diameter
Check drums for cracks and heat damage
Inspect shoes for contamination
Check return springs
Inspect rollers and retainers
Check anchor pins
Inspect camshaft movement
Check extended-lubrication seals
Inspect automatic slack-adjuster operation
Check the chamber bracket
Inspect brake chambers
Check pushrods, clevises, and pins
Inspect air hoses and fittings
Compare wheel-end temperatures
Inspect ABS sensors and tone rings
Use Meritor-approved grease when lubrication becomes due
Follow Meritor Maintenance Manual MM-96173

Common Brake-System Problems

Excessive pushrod stroke: Worn linings, an oversized drum, incorrect initial adjustment, a damaged automatic slack adjuster, worn camshaft components, or incorrect brake geometry may create excessive stroke.
Brake dragging: A restricted camshaft, damaged return springs, a binding slack adjuster, distorted shoes, trapped chamber pressure, or contaminated components may prevent complete release.
Premature lubricant loss: Damaged seals, incorrect components, improper pressure washing, heat damage, contamination, or unauthorized servicing can compromise the extended-lubrication package.
Water or contamination inside the camshaft assembly: Damaged seals, corrosion, flooding, or incorrect service procedures may allow contaminants to enter.
Uneven lining wear: Worn anchor pins, damaged rollers, camshaft movement, distorted shoes, drum problems, or incorrect components can prevent even lining contact.
Brake pulling: Unequal stroke, mismatched friction materials, contaminated linings, different chamber outputs, air-pressure differences, or uneven axle loading may cause side-to-side imbalance.
Brake fade: Excessive heat produced by repeated applications, overloading, poor brake balance, or improper descent techniques can reduce friction.
Cracked brake drum: Severe heat, operation beyond the wear limit, overloading, improper wheel installation, or impact damage may crack the drum.
Automatic slack adjuster repeatedly requires adjustment: Incorrect installation, excessive drum diameter, worn foundation-brake components, chamber-bracket movement, or an internal adjuster problem may be responsible.
Missing LX500 identification tag: The brake may be difficult to distinguish from another Q Plus package, increasing the risk of an incorrect maintenance procedure.

Safety and Service Precautions

Commercial air-brake systems contain stored pneumatic and mechanical energy. The vehicle must be secured before service begins.

Before servicing an LX500 brake:

Park on a firm and level surface
Chock the wheels
Support raised axles with approved stands
Drain or isolate air pressure as required
Cage spring brakes when the procedure requires it
Never disassemble a spring-brake chamber
Allow hot drums to cool
Wear eye and hand protection
Use approved lifting equipment
Control brake dust
Follow specified torque procedures
Use approved replacement parts

Do not lubricate the LX500 cam brake or automatic slack adjuster before the specified interval. Prematurely removing the identification tag and grease plugs can defeat the maintenance controls intended for the package.

When lubrication becomes due, the technician must follow the approved procedure, install the specified grease fittings, and use Meritor-approved synthetic grease.

The established service procedures are provided in Meritor Maintenance Manual MM-96173, covering the Q Plus LX500 and MX500 cam brakes.

Identification Information

An LX500 can be identified by tags and component features installed at the brake assembly.

Identification features include:

A brake-shoe tag identifying the brake as Q Plus
An additional lubrication-information tag attached to the chamber bracket
A tag covering the plugged chamber-bracket grease opening
Factory-installed automatic slack adjuster
Plugged lubrication openings instead of exposed grease fittings during the extended interval

Record the following information:

Vehicle manufacturer
Vehicle identification number
Vehicle model and model year
Axle manufacturer
Axle model
Axle serial number
Gross axle weight rating
LX500 identification information
Brake diameter
Brake lining width
Brake shoe number
Friction-lining code
Camshaft part number
Camshaft length
Camshaft rotation
Camshaft spline
Automatic slack-adjuster part number
Slack-adjuster length
Clevis type
Brake chamber manufacturer
Brake chamber size
Brake drum part number
Hub configuration
Wheel size
ABS configuration

The identification tag should not be removed until the maintenance procedure calls for accessing the lubrication opening.

Buying Considerations

Confirm that the brake is an LX500
Check for the lubrication-information tag
Identify the axle model and serial number
Verify steer- or drive-axle position
Confirm brake diameter
Confirm lining width
Match brake shoe geometry
Verify friction-lining material
Identify camshaft rotation
Confirm camshaft length and spline
Match the automatic slack adjuster
Identify the clevis type
Confirm brake chamber size
Check brake-drum condition
Inspect camshaft seals and bushings
Determine the vehicle’s application
Confirm the correct lubrication interval
Check whether the extended interval has expired
Use Meritor-approved replacement components
Consult the current service literature

Variants and Configurations

15-inch by 4-inch steer-axle brake
15-inch by 5-inch steer-axle brake
16.5-inch by 7-inch drive-axle brake
16.5-inch by 8-inch drive-axle brake
15-inch by 8⅝-inch drive-axle brake
19.5-inch wheel application
On-highway line-haul configuration
Vocational configuration
Bus application
Threaded-clevis automatic slack adjuster
Welded-clevis automatic slack adjuster
Left-hand camshaft
Right-hand camshaft
Different friction-material packages
Different brake chambers
Different axle ratings
ABS-equipped configuration
Application-specific brake drums

Comparison to Similar Equipment

Compared with the Meritor Q Plus Cam Brake, the LX500 adds a factory-engineered extended-lubrication package and factory-installed Meritor automatic slack adjusters. A standard Q Plus brake may follow conventional lubrication intervals.

Compared with the Meritor Q Plus MX500, the LX500 concentrates on extended camshaft and slack-adjuster lubrication. The MX500 adds proprietary extended-maintenance friction material and was designed specifically for eligible on-highway line-haul applications.

Compared with the Meritor EX+ LS Air Disc Brake, the LX500 uses shoes pressing against a drum. The EX+ LS uses a caliper and brake pads that clamp a disc rotor.

Compared with the Hendrickson MAXX22T Trailer Air Disc Brake, the LX500 is primarily documented in steer- and drive-axle truck configurations. The MAXX22T is designed for trailer air-disc-brake applications.

Compared with a conventional greasable S-cam brake, the LX500 can reduce scheduled lubrication downtime. It still requires complete brake inspections and proper service once the extended interval is reached.

Best Fit For

Vehicles originally equipped with LX500 brakes
On-highway line-haul tractors
Regional-haul trucks
Heavy-duty straight trucks
Vocational vehicles
Commercial buses
Fleets seeking reduced lubrication downtime
High-mileage operations
Vehicles using factory-installed Meritor slack adjusters
Fleets with documented preventive-maintenance programs
Operators able to track time and mileage intervals
Applications requiring proven Q Plus drum-brake operation

Related Vehicle and Trailer Types

Complete Guide to Semi Truck Types
Class 6 vs Class 7 vs Class 8 Trucks
Class 7 trucks
Class 8 trucks
Sleeper tractors
Day cab tractors
Vocational trucks
Dump trucks
Concrete mixers
Refuse trucks
Tank trucks
School buses
Transit buses
Motorcoaches
Municipal vehicles
Specialty commercial vehicles

Related Truck and Trailer Models

Related Brake System Types

Brake Systems
Air Brake Systems
Drum Brake Systems
Brake Chambers & Actuators
ABS & Electronic Braking Systems
S-cam foundation brakes
Extended-lubrication brakes
Service-brake systems
Spring parking brakes
Automatic slack-adjuster systems

Related Brake Products

Meritor Q Plus Cam Brake
Meritor EX+ LS Air Disc Brake
Hendrickson MAXX22T Trailer Air Disc Brake
Bendix ADB22X Air Disc Brake
Bendix ADB22X-LT Air Disc Brake
Haldex ModulT Air Disc Brake
ZF WABCO MAXXUS L2.0 Air Disc Brake
Bendix SR-7 Spring Brake Modulating Valve
Meritor automatic slack adjusters
Commercial brake chambers
Commercial brake drums
Q Plus brake shoes
ABS modulator valves

Related Equipment Systems

Equipment Systems
Axles & Differentials
Suspension Systems
Tires & Wheels
Compressed-air systems
Steer axles
Drive axles
Wheel-end systems
Vehicle stability systems

Related Guides

Regulatory and Compliance Notes

Commercial-vehicle brakes must meet applicable inspection, stopping-distance, and vehicle-safety requirements. The LX500 designation does not change the legal requirement to inspect and maintain the complete braking system.

Inspectors may evaluate:

Applied pushrod stroke
Brake adjustment
Lining thickness
Brake-drum condition
Chamber condition
Air leakage
Automatic slack-adjuster operation
Missing or damaged components
Friction-material contamination
ABS warning-lamp operation
Parking-brake performance

A vehicle may be placed out of service if brake stroke exceeds the applicable limit or if required components are broken, missing, loose, contaminated, or worn beyond allowable specifications.

The brake chamber, slack-adjuster length, friction material, drum, and foundation-brake dimensions must remain consistent with the vehicle’s approved braking configuration.

Real World Operating Notes

The LX500 identification tag is essential because the assembly may resemble a conventional Q Plus brake. Removing the tag too early can cause technicians to apply the wrong lubrication schedule.

The absence of exposed grease fittings during the extended interval is intentional. Technicians should not modify the assembly simply because conventional fittings are not visible.

Line-haul and vocational intervals differ. Fleets must determine the actual vehicle application instead of automatically using the 500,000-mile interval.

Once the extended interval expires, the grease plugs are removed, specified fittings are installed, and approved lubricant is applied according to the service procedure.

Extended lubrication applies to the camshaft and automatic slack adjuster. It does not extend lining, drum, chamber, hose, or brake-inspection limits.

If an automatic slack adjuster repeatedly requires manual adjustment, the underlying brake problem should be diagnosed instead of repeatedly resetting the adjuster.

Frequently Asked Questions

What is the Meritor Q Plus LX500?

The LX500 is a Q Plus S-cam drum-brake package equipped with extended-lubrication camshaft components and factory-installed Meritor automatic slack adjusters.

How is the LX500 different from a standard Q Plus brake?

The LX500 uses special seals, bushings, synthetic grease, precision components, grease plugs, and factory-installed automatic slack adjusters to provide extended lubrication intervals.

What is the LX500 lubrication interval?

For specified on-highway line-haul applications, the interval is three years or 500,000 miles, whichever comes first. For other applications, it is one year regardless of mileage.

Does the extended interval eliminate brake maintenance?

No. Brake linings, drums, chambers, pushrod stroke, springs, rollers, air lines, ABS components, and overall brake operation still require scheduled inspection.

Should the LX500 be greased during routine chassis lubrication?

Not before its specified interval. The LX500 brake and automatic slack adjuster use plugged lubrication openings during the extended period.

How can an LX500 brake be identified?

Look for the Q Plus shoe tag and the additional lubrication-information tag attached to the chamber bracket over the plugged grease opening.

What brake sizes were offered?

Documented configurations include 15-inch by 4-inch and 15-inch by 5-inch steer brakes, 16.5-inch by 7-inch and 16.5-inch by 8-inch drive brakes, and a 15-inch by 8⅝-inch drive brake for selected 19.5-inch wheel applications.

Is the LX500 the same as the MX500?

No. Both include extended-lubrication components, but the MX500 also uses a proprietary extended-maintenance friction package for specified line-haul applications.

Does the LX500 use an automatic slack adjuster?

Yes. The package includes a factory-installed Meritor automatic slack adjuster with a threaded or welded clevis, depending on configuration.

Why should an automatic slack adjuster not be repeatedly adjusted manually?

Repeated loss of adjustment may indicate worn components, an oversized drum, incorrect installation, a damaged adjuster, or another foundation-brake problem.

Can a standard Q Plus brake be converted into an LX500?

The LX500 depends on a complete package of seals, bushings, lubricant, precision components, plugs, identification, and a factory-installed slack adjuster. A standard brake should not be treated as an LX500 without an approved Meritor procedure.

How can the correct replacement parts be identified?

Use the vehicle VIN, axle model and serial number, LX500 tag, brake size, shoe and lining numbers, camshaft information, slack-adjuster number, clevis type, chamber size, and drum number.

Availability and Where to Find

Q Plus LX500 replacement components may be available through Cummins and Meritor distributors, commercial-truck dealers, heavy-duty parts suppliers, brake specialists, fleet-maintenance providers, and authorized service facilities.

Because many LX500 installations may now be found on older vehicles, buyers should confirm whether individual parts have been superseded or included in updated service kits.

Available components may include brake shoes, friction linings, hardware kits, rollers, return springs, camshafts, bushings, seals, automatic slack adjusters, chambers, brake drums, and wheel-end parts.

Current Meritor product information and technical resources are available through the Cummins Drivetrain and Braking Systems website and the Meritor brake-products section.

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