The Complete Air Disc Caliper Identification Guide

Posted by Kelvin Brake & Rebuild Ltd on 28th Jul 2026

The Complete Air Disc Caliper Identification Guide

Heavy-Duty Air Disc Caliper Identification Guide

Why Air Disc Calipers Are Commonly Misidentified

Modern commercial air disc brakes generally use an eccentric lever and sliding-caliper design. Because the operating principles are similar, products from Bendix, Meritor, WABCO, Haldex and Knorr-Bremse can look nearly identical when viewed through the wheel opening.

Correctly identifying a heavy-duty air disc brake caliper requires more than recognizing the manufacturer or matching the brake-pad shape. Many calipers share a similar external casting while differing in handedness, carrier geometry, chamber angle, mounting direction, bridge design, bolt pattern, guide-pin arrangement and vehicle application.

A caliper that appears correct may still have:

  • The wrong left- or right-hand configuration
  • Axial mounting instead of radial mounting
  • The wrong mounting-hole size or spacing
  • A different carrier bridge
  • An incompatible brake pad, rotor or chamber
  • The correct caliper body but the wrong carrier

This guide explains how to identify the major commercial-vehicle air disc caliper families used in North America:

  • Bendix ADB22X and ADB22X-LT
  • WABCO PAN 17, PAN 19, PAN 22, MAXX22T and MAXXUS
  • Haldex DB22 and DB22LT
  • Meritor D-LISA, ELSA, EX225S, EX225L and EX225H
  • Knorr-Bremse ST7 calipers used on SAF-Holland axles

The Correct Air Disc Caliper Identification Process

Use the following sequence instead of beginning with a part-number guess.

1. Record the Identification Tag

Clean the caliper tag without grinding, sanding or damaging the stamped surface. Record:

  • Manufacturer
  • Complete part number
  • Model or Serial number
  • Any left-hand or right-hand marking
  • New, remanufactured or service-exchange suffixes

A casting number should not automatically be treated as the Part number. One casting may be machined or assembled into several different finished calipers.

2. Identify the Pad-Retainer Style

The retainer distinguishes the broad manufacturer family quickly and provides a useful first indication:

These visual differences are useful for identifying the manufacturer family, but they are not enough to select an exact replacement. The identification tag, mounting arrangement, chamber angle, carrier geometry and OE reference must still be checked.

The retainer should be treated as a manufacturer clue, not a complete part-number identification.

3. Determine Axial or Radial Carrier Mounting

This describes how the carrier attaches to the torque plate.

Axial mount (Side-mounted) Image 1

An axial-mount carrier attaches to the torque plate from the side.

The carrier bolts run roughly parallel to the axle centreline. In practical terms, the bolts point in the same general direction as the axle shaft.

Think of the carrier being fastened sideways into the brake mounting structure.

Radial mount (Bottom-mounted) Image 2

A radial-mount carrier attaches through mounting points at the bottom of the carrier.

The bolts run more directly toward or away from the centre of the rotor, similar to the direction of a radius drawn from the rotor centre.

Think of the carrier being fastened upward or downward rather than sideways.

4. Determine the Brake-Chamber Angle

The chamber angle is the angle between the actuator mounting surface and the caliper body.

Common configurations include: 0° / 4° / 12° / 90° on certain Meritor families

In many North American applications:

  • 0° and 4° configurations are frequently found on trailers.
  • 12° configurations are commonly used on tractors and powered vehicle axles.

This is a useful application clue, but it is not universal.

5. Determine Left-Hand or Right-Hand Orientation

Do not identify handedness only by the side of the vehicle where the caliper was found. It is normally determined by the relationship between:

  • Wheel rotation
  • Fixed guide pin
  • Chamber position
  • Carrier orientation

A common identification method is to view the assembly from the wheel side and determine which fixed guide pin the wheel reaches first during forward rotation. The long fixed guide pin is a more reliable reference than the chamber location alone.

A left-hand caliper cannot normally replace the corresponding right-hand unit without changing the intended guide-pin and loading geometry.

6. Count and Measure the Carrier Mounting Holes

Record:

  • Total number of holes
  • Holes per side
  • Thread diameter
  • Thread pitch
  • Axial or radial arrangement
  • Centre-to-centre spacing
  • A-B distance if applicable (for e.g. 1-9/16 in, 2-9/16 in, 2-15/16 in, 3-1/4 in, 4 in, 4-1/8 in)

Common heavy-duty caliper carrier threads include:

  • M14 × 1.5
  • M16 × 1.5
  • M18 × 1.5
  • M20 × 1.5
  • M20 × 2.0
  • M20 × 2.5

A correct thread diameter with the wrong pitch is not compatible.

7. Identify the Visual Style

The bridge is the carrier section spanning the rotor and supporting the pad/caliper relationship.

common Types:

  • Flat bridge
  • Pocket bridge
  • Slotted bridge
  • Window bridge

Two calipers may have the same chamber angle and handedness but use different bridge geometry. This can change clearance around the rotor, axle, carrier or suspension hardware.

8. Verify the Brake Pad Shape

Pad shape can confirm a caliper family, but it should not be the first or only identification method. Different calipers may use:

  • The same friction shape with different hardware
  • The same pad outline with different friction grades
  • Similar pad shapes with different overall dimensions
  • Different wear-sensor arrangements
  • Different retainer springs or abutment hardware

Use the pad number as supporting evidence after the caliper model is identified.

9. Cross-Reference the Complete OE Number

The final replacement decision should be based on the complete service number, not a partial number or model family. Verify:

  • Exact manufacturer number
  • Superseded number
  • Vehicle or axle manufacturer number
  • Handedness
  • Carrier inclusion
  • Application notes

Quick Manufacturer Identification Table

Family Primary visual clue Important secondary checks
Bendix ADB22X / ADB22X-LT Solid pad-retainer bar with clevis pin Chamber angle, axial/radial carrier, mounting-hole count, tag and K-number
WABCO PAN Open retainer with angled end and welded nut PAN model, rim size, carrier thread size, WABCO number
WABCO MAXX Open retainer with squared end and no welded nut MAXX22T versus MAXXUS, axial/radial mount, truck/trailer application
Haldex DB22 / DB22LT Snap-on retainer and external guide-pin covers Standard, Dana or wide bolt pattern; tag and serial number
Meritor EX225L / EX225H Solid top-bolted retainer bar L2/H2/H3 tag, bridge style, hole pattern, A-B distance and handedness
D-LISA / ELSA Meritor-style retainer; model-specific pad and casting Tag, vehicle application, pad family and exact service number
Knorr ST7 on SAF-Holland Bendix/Knorr-style solid retainer and clevis pin SAF axle application, 2-hole axial carrier, exact Knorr/SAF number

Bendix ADB22X and ADB22X-LT Caliper Identification

Recognizing the Bendix Family

The Bendix ADB22X family normally uses:

  • A solid pad-retainer bar
  • Clevis-pin retention
  • A twin-tappet actuation design
  • Identifiable long and short guide-pin positions
  • Bendix identification tags and K-series service numbers

The solid bar and clevis pin are strong manufacturer-family clues, but Knorr-Bremse SK7, ST7, SB7 and SN7 products may use a similar retainer system. The tag and mounting arrangement must therefore be checked.

Common ADB22X Configurations

0° axial-mount trailer calipers

Common on:

  • SAF-Holland trailer axles
  • Hendrickson trailer axles
  • Other North American trailer applications

Typical identifying features include:

  • Two- or three-hole side-mounted carrier
  • 0° chamber position
  • Separate left- and right-hand assemblies

Examples application Part Numbers include:

  • 5400101100 / 03080005901Z / K012341
  • 5400101200 / 03080006001Z / K012342
  • 802984 / K113887X
  • 802985 / K113888X

12° axial-mount truck calipers

These are frequently used on tractors other than certain Freightliner or Western Star configurations.

Common references include:

  • K081142 / K109961X
  • K081143 / K109962X

The carrier mounts from the side, while the chamber sits at an angled truck position.

12° radial-mount truck calipers

Certain Freightliner and Western Star applications use a radial or bottom-mounted carrier.

Common references include:

  • K081256 / K109957X
  • K081257 / K109958X

These should not be interchanged with the visually similar axial-mounted version.

ADB22X Versus ADB22X-LT

The ADB22X-LT is a lighter-weight configuration developed for selected trailer applications. Bendix has continued to refine the ADB22X platform, including weight-focused versions for linehaul and lighter-duty applications.

Do not identify the LT version merely because the caliper appears lighter or has a different carrier opening.

Bendix Calipers Guide

Type Caliper (New) Caliper (Reman) Carrier With Carrier (New) With Carrier (Reman) Pads Rotor Pin Kit Spring Brake
ADB22
22.5" / 23K		 FPK019180-G (RH) 0° FPK019180X (RH) 0° FPK043288 | LH/RH Hendrickson FPK802984WC-G RH FPK11887WCX RH PE1369HK FP802081 FPK10194 FPK132352
FPK019181-G (LH) 0° FPK019181X (LH) 0° FPK802985WC-G LH FPK11888WCX LH
ADB22 SAF Trailer FPK019180-G (RH) 0° FPK019180X (RH) 0° FPK2019050 | LH/RH SAF FPK012341WC-G RH FPK012341WCX RH
FPK019181-G (LH) 0° FPK019181X (LH) 0° FPK012342WC-G LH FPK012342WCX LH
ADB22 Freightliner (12°) FPK081258-G (RH) 12° FPK081258X (RH) 12° FPK056889 | LH/RH Freightliner FPK081256WC-G RH FPK109957WCX RH FP802082
FPK081259-G (LH) 12° FPK081259X (LH) 12° FPK081257WC-G LH FPK109958WCX LH
ADB22 All Makes (12°) FPK081258-G (RH) 12° FPK081258X (RH) 12° FPK051853 | LH/RH FPK081142WC-G RH FPK109961WCX RH
FPK081259-G (LH) 12° FPK081259X (LH) 12° FPK081143WC-G LH FPK109962WCX LH
ADB22LT K165794 RH 0° FPK129301 | Hendrickson LT FPK149714WC-G FPK165794WCX        
K165795 LH 0° FPK149715WC-G FPK165795WCX        

WABCO PAN and MAXX Caliper Identification

WABCO air disc calipers are commonly recognized by their open pad-retainer bar. However, PAN and MAXX products have different retainer details and mounting applications.

WABCO Tag Number Patterns

Typical WABCO numbers may be printed with spaces:

  • 40 175 092 0
  • 40 195 038 0
  • 40 225 036 0
  • 640 322 050 0
  • 640 222 002 0

They may also appear without spaces:

  • 401750920
  • 401950380
  • 402250360
  • 6403220500
  • 6402220020

The supplied caliper-identification guide uses these broad number patterns:

Model Typical number family
PAN 17 40 175…
PAN 19 40 195…
PAN 22 40 225…
MAXXUS 22 640 322…
MAXX 22T 640 222…

WABCO PAN 17

PAN 17 is normally associated with 17.5-inch wheel applications.

Identification characteristics commonly include:

  • Smaller caliper envelope
  • Open WABCO retainer
  • Axial carrier mounting
  • Three M14 × 1.5 mounting holes per side in common North American trailer configurations
  • Hendrickson or Cozad axle applications

Examples include:

  • 640175073 — right-hand
  • 640175072 — left-hand

The smaller carrier thread and wheel application help distinguish PAN 17 from PAN 19 and PAN 22.

WABCO PAN 19

PAN 19 is commonly used with 19.5-inch wheel systems and selected trailer applications.

PAN 19 ONLY COMES WITH IMT STYLE CARRIER. Typical North American PAN 19-1 identifiers include:

  • Open retainer bar
  • Axial carrier
  • Three M18 × 1.5 mounting holes per side
  • NIPPLE IS CONNECTED TO CALIPER CASTING
  • GUIDE PIN HOLE MOUNT LONGER ON THE SIDE OF THE CALIPER TO INDICATE LH OR RH.
  • Numbers such as 6401951020 and 6401951010

Do not select PAN 19 solely because the rotor diameter appears smaller than a 22.5-inch-wheel brake. Confirm the tag and bolt pattern.

WABCO PAN 22

PAN 22 is used in several 22.5-inch trailer configurations.

NIPPLE IS STICKING OUT FROM CALIPER CASTING. GUIDE PIN HOLE MOUNT LONGER ON THE SIDE OF THE CALIPER TO INDICATE LH OR RH.

The same broad model family can have significantly different carriers.

Examples include:

Hendrickson applications

  • Three M20 mounting holes per side
  • 6402250810 or 6402250800 families
  • CENTER PORTION IS STRAIGHT

IMT, Dexter and Ridewell applications

  • Three M16 × 1.5 mounting holes per side
  • Different left- and right-hand service numbers
  • CENTER PORTION IS CURVED

SAF-Holland applications

  • Two M18 × 1.5 mounting holes per side
  • Different carrier from the Hendrickson version

Therefore, “PAN 22” is not a complete replacement specification. The axle manufacturer and carrier pattern are essential.

Type Caliper (No Carrier) Carrier Caliper With Carrier (NEW) Caliper With Carrier (Reman) Brake Pads Rotor Pin Kit Spring Brakes
PAN 17 | 17.5" wheels/10K Nm FP40175090X FP30186 | PAN 17 LH IMT axle FP40175072WC-G FP40175072WCX PE1518HK (240 cm²x19mm) FP75180 (330x34mm) FPK30143 (Type 20 actuation) FPK041960 (20/24)
FP40175091X FP30187 | PAN 17 RH IMT axle FP40175073WC-G FP40175073WCX
PAN 19 | 19.5" wheels/17K Nm FP40195027X FP30188 | PAN 19 LH IMT axle FP40195037WC-G FP40195037WCX PE1438HK (292 cm²x21mm) FP71601 (375x45mm) FPK30123 (Type 24 actuation)
FP40195028X FP30189 | PAN 19 RH IMT axle FP40195038WC-G FP40195038WCX
PAN 22 | 22.5" wheels/23K Nm FP40225011X FP30190 | PAN 22 LH IMT axle FP40225015WC-G FP40225015WCX PE1777HK (340 cm²x23mm) FP76613 (430x45mm)*
FP30196 | PAN 22 LH Hendrickson axle FP6402250800WC-G FP6402250800WCX FP76810 (430x45mm)
FP40225012X FP30191 | PAN 22 RH IMT axle FP40225016WC-G FP40225016WCX FP76613 (430x45mm)*
FP30197 | PAN 22 LH Hendrickson axle FP6402250810WC-G FP6402250810WCX FP76810 (430x45mm)

WABCO MAXX22T

MAXX22T SINGLE PISTON is commonly found on trailer axles.

Typical clues include:

  • Open retainer with a more squared end than PAN
  • No welded retainer nut in the characteristic location used on PAN designs
  • Axial carrier mounting
  • Three mounting holes per side in common Hendrickson applications
  • WABCO number family beginning with 640222

Examples include:

  • 6402220080 — right-hand
  • 6402220070 — left-hand

ZF describes the broader MAXX platform as covering applications from 17.5- to 22.5-inch wheels, with model-specific sensing and adjuster configurations.

CALIPER (CASSETTE) CARRIER # COMPLETE CALIPER W/CARRIER NEW CALIPER W/CARRIER AXEL STYLE / MOUNT
K2556-MAXX22T (RH) FP2556 FP6402220060WCX FP6402220060WC-G HENDRICKSON
K2555-MAXX22T (LH) FP2555 FP6402220050WCX FP6402220050WC-G HENDRICKSON

WABCO MAXXUS

MAXXUS SINGLE PISTON is commonly encountered on North American tractors, particularly Freightliner and International/Navistar applications.

Typical clues include:

  • MAXX-style squared open retainer
  • Radial carrier mounting
  • Two mounting holes per side in common applications
  • WABCO numbers beginning with 640322

Common handed references include:

  • 640322050 — right-hand
  • 640322051 — left-hand

Do not interchange MAXXUS and MAXX22T merely because they use related pad or service components. MAXXUS commonly uses a truck radial carrier, while MAXX22T commonly uses a trailer axial carrier.

CALIPER (CASSETTE) CARRIER # COMPLETE CALIPER W/CARRIER NEW CALIPER W/CARRIER AXEL STYLE / MOUNT
K2554-MAXXUS (RH) FP2554 FP6403220510WCX FP6403220510WC-G BOTTOM MOUNT
K2553-MAXXUS (LH) FP2553 FP6403220500WCX FP6403220500WC-G BOTTOM MOUNT
K2554-MAXXUS (RH) N/A FP6403221050WCX N/A SIDE MOUNT
K2553-MAXXUS (LH) N/A FP6403221040WCX N/A SIDE MOUNT

    Haldex DB22 and DB22LT Caliper Identification

    Haldex air disc calipers are commonly distinguished by:

    • A snap-on solid pad-retainer
    • External guide-pin covers
    • Haldex part-number and serial-number tag
    • Bolt-pattern-specific carrier arrangements

    Older Haldex products may use a bolt-on retainer resembling a Meritor design, making the external guide-pin covers an important secondary clue.

    Haldex DB22

    Haldex lists North American ModulX DB22 calipers in more than one mounting pattern, including:

    • Standard bolt pattern
    • Dana bolt pattern

    This means “DB22” alone is not enough to select the replacement. Verify:

    • Haldex service number
    • Carrier bolt pattern
    • Axle manufacturer
    • Mounting-hole spacing
    • Left- or right-hand configuration
    • Whether the carrier is included

    Haldex DB22LT

    Haldex identifies a DB22LT North American caliper with a wide bolt pattern.

    The LT designation should not be assumed solely from the presence of a lightweight-looking casting. The wider carrier pattern and complete Haldex service number are more reliable identifiers.

    Haldex also uses similar DB22LT terminology in its European ModulT trailer documentation. That European DBT22LT/ModulT product should not automatically be treated as the same replacement as a North American ModulX DB22LT. The application guide, product generation and complete service number must match.

    Haldex Calipers

    Type Caliper With Carrier (New Conversion Kit) Rotor Guide Pin Kit Spring Brakes
    DB22LT 22.5"-24.5" wheels
    18–23K Nm    		 FP790-94025RHWC-G RH w/pads FP76810
    220mm Pilot (430x45mm)    		 FPK60103 FPK132352
    (18/24)
    FP790-94025LHWC-G LH w/pads
    Caliper (Cassette) Complete Caliper w/Carrier Axle Style
    DB22 (Universal) FP790-92799WCX Hendrickson
    DB22LT (Universal) FP790-94829WCX Hendrickson
    Haldex / Dana ESD-225 (Universal) FP790-94049WCX Hendrickson

    Meritor D-LISA, ELSA, EX225L and EX225H Identification

    Meritor-style calipers commonly use a solid pad-retainer bar secured by a bolt aligned at the top of the assembly.

    This identifies the broad Meritor family, but exact selection requires careful measurement because EX225 variants can differ by:

    • L2, H2 or H3 model
    • Left or right hand
    • Axial or radial carrier
    • 0°, 4°, 12° or 90° chamber position
    • Flat, pocket, slot or window bridge
    • Four, six or eight mounting holes
    • M16, M18 or M20 threads
    • A-B distance
    • Truck, trailer, steer, drive or transit application

    The supplied identification guide notes that Meritor tags commonly show model forms such as EX225L 201/202, EX225H 201/202 and EX225H 301/302.

    Meritor EX225L

    EX225L2 is widely used in Volvo, Mack truck and trailer applications.

    It appears in many carrier configurations:

    Caliper Position Pads Repair Kits Mounting Hole A-B Distance Cross References Application
    EX225L221 With Carrier (LH) Radial 4° PE1370HK FPKEX225L 4 Holes, Size:M20 × 1.5 1-9/16" EX225L221, EX225L219, ATC-AD30-438 Volvo, Mack Truck
    EX225L222 With Carrier (RH) Radial 4° 4 Holes, Size:M20 × 1.5 1-9/16" EX225L222, EX225L220, ATC-AD30-437 Volvo, Mack Truck
    EX225L235 With Carrier (LH) Axial 4° pocket, with inner beam 6 Holes, Size:M20 × 2.0 2-15/16" Volvo: 23675019, 23582848, 23582844 | EX225L235, ATC-AD30-456 Mack, Volvo, Hino, other heavy-duty Trucks
    EX225L236 With Carrier (RH) Axial 4° pocket, with inner beam 6 Holes, Size:M20 × 2.0 2-15/16" Volvo: 23675020, 23582850, 23582846 | EX225L236, ATC-AD30-455 Mack, Volvo, Hino, other heavy-duty Trucks
    EX225L237 With Carrier (LH) Axial 4° pocket, without inner beam 6 Holes, Size:M20 × 2.0 2-15/16" Volvo: 23675022, 23582864, 23582860 | EX225L237, ATC-AD30-466 Mack, Volvo, other heavy Truck & Trailer
    EX225L238 With Carrier (RH) Axial 4° pocket, without inner beam 6 Holes, Size:M20 × 2.0 2-15/16" Volvo: 23675023, 23582866, 23582862 | EX225L238, ATC-AD30-465 Mack, Volvo, other heavy Truck & Trailer
    EX225L243 With Carrier (LH) Radial 12° pocket 4 Holes, Size:M20 × 1.5 1-9/16" Volvo: 23675034, 23582876 | EX225L243, EX225L247, EX225L269 (Window), ATC-AD30-238 Steer/Axle Linehaul & Volvo HD Trucks
    EX225L244 With Carrier (RH) Radial 12° pocket 4 Holes, Size:M20 × 1.5 1-9/16" Volvo: 23675035, 23582878 | EX225L244, EX225L248, EX225L270 (Window), ATC-AD30-237 Steer/Axle Linehaul & Volvo HD Trucks
    EX225L255 With Carrier (RH) Axial 12° pocket 6 Holes, Size:M20 × 1.5 2-15/16" EX225L251, EX225L255, ATC-AD30-486 HD, Transit, Refuse Truck & Trailers
    EX225L256 With Carrier (LH) Axial 12° pocket 6 Holes, Size:M20 × 1.5 2-15/16" EX225L252, EX225L256, ATC-AD30-485 HD, Transit, Refuse Truck & Trailers
    EX225L261 With Carrier (LH) Axial 12° window 6 Holes, Size:M20 × 2.5 2-9/16" EX225L261, EX225L273, ATC-AD30-206 Freightliner Cascadia Steer Axle
    EX225L262 With Carrier (RH) Axial 12° window 6 Holes, Size:M20 × 2.5 2-9/16" EX225L262, EX225L274, ATC-AD30-205 Freightliner Cascadia Steer Axle
    EX225L265 With Carrier (LH) Axial 12° window 6 Holes, Size:M20 × 2.0 2-15/16" EX225L265, ATC-AD30-256 HD Truck & Trailers
    EX225L266 With Carrier (RH) Axial 12° window 6 Holes, Size:M20 × 2.0 2-15/16" EX225L265, ATC-AD30-255 HD Truck & Trailers
    EX225L271 With Carrier (LH) Axial 12° window 6 Holes, Size:M20 × 2.0 3-1/4" EX225L271, ATC-AD30-296 Trailers
    EX225L272 With Carrier (RH) Axial 12° window 6 Holes, Size:M20 × 2.0 3-1/4" EX225L272,  ATC-AD30-295 Trailers

    Meritor EX225H

    EX225H calipers include H2 and H3 variants. EX225H2 is commonly used on Mack/Volvo, EX225H2 PACCAR/International and EX225H3 transit configurations.

    Caliper Position (ALL flat Bridge) Pads Repair Kits Mounting Hole Hole Distance Cross References Application
    EX225H201 With Carrier (RH) Axial 0° PE1311HK FPKEX225H 6 Holes, M20 × 1.5 4-1/8" EX225H203, EX225H201, NUGEON 99B92201, MCI 04-01-1114 ATC-AD32-046 PACCAR/Peterbilt, International, Autocar, coach, refuse Trucks Steer & Drive Axles
    EX225H202 With Carrier (LH) Axial 0° 6 Holes, M20 × 1.5 4-1/8" EX225H204, EX225H202, NUGEON 99B92202, MCI 04-01-1115 ATC-AD32-045 PACCAR/Peterbilt, International, Autocar, coach, refuse Trucks Steer & Drive Axles
    EX225H205 With Carrier (RH) Axial 0° 8 Holes, M20 × 1.5 4-1/8" EX225H205 8-bolt family Refuse, International various axle positions
    EX225H206 With Carrier (LH) Axial 0° 8 Holes, M20 × 1.5 4-1/8" EX225H205 8-bolt family Refuse, International various axle positions
    EX225H225 With Carrier(LH) Radial 12° 4 Holes, M20 × 1.5 1-9/16" EX225H225, EX225H215, ATC-AD32-238 | Volvo: 23675133, 21906491 Mack and Volvo Trucks Drive Axles
    EX225H226 With Carrier(RH) Radial 12° 4 Holes, M20 × 1.5 1-9/16" EX225H226, EX225H216, ATC-AD32-237 | Volvo: 23675134, 21906497 Mack and Volvo Trucks Drive Axles
    EX225H227 With Carrier (LH) Axial 0° 6 Holes, M20 × 2.0 2-5/16" EX225H227, EX225H217, ATC-AD32-036 | Volvo: 23675025, 22188310, 22188312 Mack and Volvo Trucks Steer Axles
    EX225H228 With Carrier (RH) Axial 0° 6 Holes, M20 × 2.0 2-5/16" EX225H228, EX225H218, ATC-AD32-035 | Volve: 23675026, 22188311, 22188315 Mack and Volvo Trucks Steer Axles

    Meritor ELSA

    ELSA is a separate Meritor air disc brake family used in several truck, bus and European-derived applications.

    Depending on the generation, ELSA references may appear alongside EX225 applications. For example, some ELSA 3 Mack/Volvo configurations share application relationships with EX225H-style caliper families.

    Caliper Position (All Pocket Bridge) Pads Bridge  Mounting Hole Hole Distance Cross References Application
    LRG723NX With Carrier (LH) Axial 0° PE1310HK Pocket Bridge 6 Holes, M18 × 1.5 4-1/8" LRG723NX Transit Bus
    LRG722NX With Carrier (RH) Axial 0° 6 Holes, M18 × 1.5 4-1/8" LRG722NX Transit Bus
    LRG749NX With Carrier (LH) Axial 0° 6 Holes, M18 × 1.5 4-1/8" LRG749NX Van Hool CX/TX with DANA / Spicer Axle
    LRG748NX With Carrier (RH) Axial 0° 6 Holes, M18 × 1.5 4-1/8" LRG748NX Van Hool CX/TX with DANA / Spicer Axle
    LRG662NX With Carrier (LH) Radial ELSA2 6 Holes, M18 × 1.5 4-1/8" MXC9308027 | MAN: 81508046405, 81508046427, 81508046429 Van Hool Buses, Coaches & Trailers
    LRG663NX With Carrier (RH) Radial ELSA2 6 Holes, M18 × 1.5 4-1/8" MXC9308028 | MAN: 81508046406, 81508046426, 81508046428 Van Hool Buses, Coaches & Trailers

    Do not treat all ELSA numbers as EX225H equivalents.

    Meritor D-LISA

    D-LISA is another distinct Meritor family commonly used on MCI Buses. It uses its own: Caliper design, Pad profile

      Caliper Position (One-Piece Bridge) Pads Mount Mounting Hole Hole Distance Cross References Application
      LRG630 With Carrier (LH) Perpendicular PE1312HK

      Axial Mount, Perpendicular Chamber Mount, One-Piece Bridge

      		 6 Holes, M20 × 1.5 1-12/16" MXC9305009, 68032864, MCI 04-01-1020

      MCI E Series Steering and Trailing Axles 1996–2004
      LRG631 With Carrier (RH) Perpendicular 6 Holes, M20 × 1.5 1-12/16" MXC9305010, 68032865, MCI 04-01-1021 MCI E Series Steering and Trailing Axles 1996–2004

      Understanding Meritor Bridge Styles

      Flat bridge

      The bridge surface is comparatively continuous and flat.

      Pocket bridge

      The bridge contains recessed or pocketed areas.

      Slotted bridge

      The bridge includes defined open slots.

      Window bridge

      The bridge has larger window-like openings.

      Bridge design matters because it can affect:

      • Rotor clearance
      • Pad-carrier support
      • Carrier stiffness
      • Suspension clearance
      • Brake chamber positioning

      SAF-Holland ST7 Caliper Identification

      The term SAF-Holland ST7 caliper is commonly used in the aftermarket, but the brake itself is a Knorr-Bremse design used on SAF-Holland axle applications.

      Recognizing ST7

      ST7 shares Bendix/Knorr visual characteristics, including:

      • Solid pad-retainer bar
      • Clevis-pin retention
      • Knorr-style caliper architecture
      • Axle-specific carrier

      Because ADB22X, SK7 and ST7 can look similar, the tag and carrier must be verified.

      Common North American SAF-Holland ST7 Configuration

      The supplied application catalogue identifies:

      • 0° chamber position
      • Axial carrier mounting
      • Two mounting holes per side
      • SAF-Holland trailer axles from approximately 2017 onward
      • Separate right- and left-hand units

      Common references include:

      Right-hand

      • 03080009800
      • K097529K50

      Left-hand

      • 03080009700
      • K097530K50

      Do not substitute an ADB22X or SK7 unit solely because the pad-retainer design appears similar.

      Air Disc Caliper Inspection Before Ordering

      Identification and condition assessment should be completed separately. The correct model may still require replacement rather than a basic repair.

      Condition inspection

      Check:

      • Cracks in caliper or carrier casting
      • Damaged or stripped carrier threads
      • Seized guide pins
      • Split guide-pin boots
      • Torn tappet boots
      • Water or contamination inside the mechanism
      • Uneven inner and outer pad wear
      • Abnormal rotor contact
      • Excessive caliper movement
      • Adjuster operation
      • Chamber leakage
      • Heat damage
      • Severe corrosion around guide-pin bores
      • Missing retainer hardware
      • Damaged wear-sensor wiring

      Follow the manufacturer’s current service procedure before operating the adjuster or disassembling the caliper. ZF, Bendix, Haldex and other manufacturers publish model-specific repair manuals because adjustment limits, approved repair areas and tooling differ between families.

      Repair Kit or Complete Caliper?

      A guide-pin or boot kit may be appropriate when:

      • The casting is undamaged
      • Carrier threads are intact
      • The adjuster operates correctly
      • Internal contamination has not occurred
      • Guide-pin bores remain within specification
      • The repair is authorized by the manufacturer
      • The correct model-specific kit is available

      A complete caliper is generally the safer choice when:

      • The casting is cracked
      • The carrier is distorted
      • Threads are stripped
      • The adjuster or internal mechanism has failed
      • Water has entered the actuation mechanism
      • Severe heat damage is present
      • The slide system is seized beyond the approved repair scope
      • The identification cannot be confirmed
      • Multiple incompatible parts have previously been installed

      Remanufactured calipers should be treated as specific finished assemblies, not generic rebuilt castings. We have controlled remanufacturing processes involving disassembly, replacement of worn parts, testing and reassembly to defined OEM standards.

      Caliper Installation Notes

      ✔ Secure the vehicle, block the wheels, build air pressure to 100–120 psi, and release the spring brakes before adjustment.
      ✔ BENDIX ADB22/ADB22LT, SK7 and ST7: turn clockwise until pad contact, then back off 2 clicks.
      ✔ WABCO MAXXUS: turn clockwise until pad contact, then back off 1/4 turn counterclockwise.
      ✔ WABCO PAN17/PAN19/PAN22/MAXX22T: turn counterclockwise until pad contact, then back off 1/4 turn clockwise.
      ✔ Follow the manufacturer’s current service procedure and avoid overtightening.

      Final Identification Rules

      A reliable air disc caliper match should satisfy all of the following:

      • Manufacturer family matches
      • Exact model family matches
      • Identification tag or OE number matches
      • Left/right orientation matches
      • Chamber angle matches
      • Axial/radial mounting matches
      • Carrier bolt count matches
      • Thread size and pitch match
      • A-B distance matches
      • Bridge style matches
      • Vehicle and axle application match
      • Pad and rotor compatibility match

      A caliper should not be purchased solely because:

      • It accepts the same brake pad
      • It appears visually similar
      • It has the same chamber angle
      • It came from the same side of another truck
      • The casting number matches
      • The model family is the same
      • The supplier’s cross-reference omits the carrier details

      The safest method is to identify the manufacturer from the retainer and tag, establish the exact mechanical configuration, and then confirm the complete OE interchange against the vehicle or axle application.

      !