SAE--J360-2001

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SAE SAE J360 Revised DEC2001

3.3.13.2

Instrumentation and Equipment

Force Measuring Device—0 to 0 N (0 to 200 lbf), to measure hand or foot application force.

Decelerometer—0 to 9.8 m/s2 (0 to 32.2 ft/s2), to measure vehicle deceleration during burnish or establishingIBT.

Temperature Measuring Device—0 to 540 °C (0 to 1000 °F), to measure parking brake lining pad or shoe asper figure described in SAE J2115 and display monitor/recording brake lining temperature accurate to ±5.6 °C(±10 °F).

Stopwatch—0 to 5 min, method to measure and document test time.

Pressure Gauge—0 to 900 kPa (0 to 130 lbf/in2) for air brake application pressure measurements.Inclinometer—0 to 30%, or other method to measure surface grade/slope.Axle Weight Measuring Device—±1.0% of indicated weight.

A device, ±50 mm (±2.0 in), or method to measure vehicle movement once the parking brake has beenapplied.

Vehicle Information and Data

Test Data Sheet 1 (Figure 1) to be used as a work sheet during testing.

Vehicle information shall be documented as described in SAE J1626 section 5, Figures 1A through 1C (seeData Sheet 1 of SAE J1626).

Vehicle Conditions—To insure the accuracy and validity of results, the following conditions should be met:On the brakes applied by the parking brake system, use new thermocouple lining and drums or discs oforiginal equipment material and install in accordance with the vehicle manufacturer's specifications.Parking brake assemblies and actuation systems are to be installed, lubricated, adjusted and inspected inaccordance with the vehicle manufacturer's specifications.

Tires must not be more than 20% worn, largest diameter specified for the vehicle at the test GVWR andinflated to the pressure specified by the vehicle manufacturer for the GVWR, measured cold (at thebeginning of each test day).

For driveline type parking brakes, the rear axle ratio should be at the specified manufacturer value togenerate the highest torque in combination with 4.3.3 tire size during grade holding.

The vehicle is to be tested in both the fully loaded and unloaded condition. For the purposes of this testprocedure, fully loaded shall be the manufacturer's gross vehicle weight rating (GVWR) distributedproportionately to individual axle weight ratings (GAWR's) per SAE J1626 section 3. Truck, tractor andbuses shall be loaded to GVWR. The unloaded vehicle shall be as defined in SAE J1626 section 3.NOTE—FMVSS 121 allows the option of performing the grade holding test at LLVW and GVWR or the

static retardation force parking brake test at GVWR.The sequence of testing may be arranged to suit the desired order of vehicle loading and unloading.

3.3

3.43.53.63.73.8

4.4.14.2

4.34.3.1

4.3.2

4.3.3

4.3.4

4.3.5

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SAE SAE J360 Revised DEC2001

FIGURE 1—DATA SHEET 1—GRADE HOLDING PARKING BRAKE

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SAE SAE J360 Revised DEC2001

5.5.15.25.35.4

Test Conditions and Facilities

Ambient air temperature must be between 0 and 38 °C (32 and 100 °F).Wind velocity should not exceed 24 km/h (15 mph).

Unless otherwise specified, the transmission shall be in neutral or the clutch depressed during burnish snubs.All vehicle openings (doors, windows, hood, etc.) must be closed except as required for instrumentationpurposes.

Roadway shall be flat with no more than a 1% grade in all directions, including crown for burnish snubs andinitial brake temperature (IBT) conditioning.

Automatic adjusters must remain activated for the duration of the test.

Unless otherwise specified, parking brakes can be adjusted per the vehicle manufacturer's procedure atanytime.

Individual parking brake lining temperatures should be less than 95 °C (200 °F) when being adjusted orchecked.

Conduct the test on a 20% (+1%/–0%) dry, smooth Portland cement concrete surface (or other surface ofequivalent coefficient of surface friction) that is free from loose materials and has a grade equal to or greaterthan any specified grade requirement for the test vehicle, as designated in SAE J293.

5.5

5.65.7

5.8

5.9

5.10Initial Brake Temperature (IBT)—For vehicles with a parking brake system that utilizes friction elements of the

service brake system, the lining temperature just prior to any parking brake test must be between 65 and 95 °C(150 and 200 °F). Temperature condition the lining material by conducting brake snubs from to 32 km/h (40to 20 mph) speed at 3 m/s2 (10 ft/s2) deceleration at 1.6 km (1 mile) intervals (If speed or deceleration is notattainable, run at maximum speed or deceleration).

For vehicles with a parking brake system that does not utilize the service brakes including hydraulic brakeschool bus, the lining material temperature just prior to any parking brake test shall not be more than 65 °C(150 °F) (when the temperature of components on both ends of an axle are averaged or the temperature of thedriveline type parking brake material). Temperature condition the lining material per the vehicle manufacturesrecommendation but not to exceed the 65 °C (150 °F) requirement per FMVSS 105.

5.11With variable input systems, conduct the test to establish the applied manual effort or pressure required to lock

the braked wheels. With pressure-applied/mechanically locked actuators, make observations after releasingthe application pressure.5.12With fixed input systems, determine the manual effort required to actuate the system control and observe

whether the braked wheels lock or roll.5.13For vehicles having any equipment (such as driver-controlled interaxle differentials or multi-speed axles),

which can be placed in or out of engagement by the driver so as to vary either the number of axles braked orthe amount of torque imposed on the parking brake or brakes, conduct the test to determine parkingperformance under the condition that requires highest parking brake torque and under the condition thatrequires highest tire-to-road tractive force.5.14Parking brake systems employing service brakes or those employing non-service brakes for which the

manufacturer provides the purchaser with a published burnish procedure need not be tested before burnishingbecause of the difficulty in obtaining reliable and repeatable pre-burnish data.

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SAE SAE J360 Revised DEC2001

5.15Vehicles equipped with parking brake systems employing cable or rod actuation of service brakes shall be

allowed to roll off the grade after each data reading. This will improve repeatability of results by allowingrealignment between axle and actuation parts and by removing system hysteresis.5.16Method of Conducting Grade Holding Test5.16.1TEST PREPARATION

5.16.1.1Install instrumentation and equipment based on the type of parking brake system as described in Section 3.5.16.1.2Install new thermocouple lining and drums/discs. Lining grind and surface finish of drums/discs, including

all other brake components must be within vehicle manufacturer's specifications.5.16.1.3Adjust brakes to vehicle manufacturer's specifications. Where applicable, measure and record pushrod

travel with only service brakes applied at 620 kPa (90 psi) at chamber.5.16.1.4Adjust vehicle weight to appropriate load condition as per test sequence.

5.16.1.5For vehicles with a parking brake system that does not utilize the service brakes, burnish brakes as

described in 6.1.1.5.16.1.6For vehicles with a parking brake system that utilize friction elements of the service brake system, burnish

the brakes as described in 6.2.1.5.16.1.7Install/prepare device to measure vehicle movement on the grade.

5.16.1.8Test Facility—A 20% (+1%/–0%) grade of dry smooth Portland cement concrete or equivalent as

described in 5.9.5.16.1.9For hydraulic brake school buses, install force transducer for foot and/or hand control efforts.

NOTE—It is recognized that the weight of the truck-tractor/test trailer combination (GCW) is greater than

the tractor GVWR. If the combination will not park on the test grade at the GCW, reduce theweight to equal truck-tractor GVWR and retest.

5.16.1.10

For vehicles having any equipment (axle differential locks or multi-speed axles) which is driver-controlled, the test must be conducted in the conditions which requires the highest parking brake torque.

5.16.2TEST PROCEDURE

5.16.2.1Temperature condition the parking brake lining material based on vehicle type per 5.10.5.16.2.2Charge air brake system reservoirs to compressor governor cut-out pressure.5.16.2.3Place driver selected equipment in desired condition.

5.16.2.4Ascend 20% grade (dry Portland cement concrete or equivalent surface), stop, and hold with the service

brakes.5.16.2.5With vehicle declutched or transmission in neutral, actuate brakes as follows:

5.16.2.5.1Air-Braked Vehicle—Apply and hold service brakes by using maximum treadle (pedal) travel with system

at compressor cut-out pressure. Apply parking brake(s). Release service brakes after parking brakecontrol is at the fully-applied position.

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SAE SAE J360 Revised DEC2001

5.16.2.5.2Hydraulic-Braked Vehicle—Apply and hold service brakes with 667 N (150 lbf) force. Apply parking

brake(s). Release service brakes after parking brake control is at the fully-applied position. Hydraulicbrake school buses with a GVWR > 4540 kg (10 000 lb) apply a maximum of 667 N (150 lb) to the footcontrol or 556 N (125 lb) to the hand control parking brake. If the vehicle does not remain stationary,reapplication of the service brakes to hold the vehicle stationary, with reapplication of the force to theparking brake control at the level specified as appropriate for the vehicle being tested may be used twiceto attain a stationary position per FMVSS 105.5.16.2.6Turn off engine.

5.16.2.7For variable input systems, record the minimum applied effort or pressure to lock the braked wheels. For

fixed input systems, record the applied effort or pressure and observe if the braked wheels are rolling orlocked. Observe vehicle stability and record performance whether vehicle holds for at least 5 min or slideson the grade.5.16.2.8Apply service brakes and release the parking brake and repeat test to obtain a minimum of three

consistent readings. If the system is a cable or rod actuated service brake, remove vehicle from gradeafter each reading as noted in 5.15.5.16.2.9Repeat all steps in 5.16.2 except reposition the vehicle in the descending direction. Temperature condition

the parking brake lining material, if necessary, to achieve specified IBT per 5.10.5.16.2.10

Repeat all steps in 5.16.2 for each test condition of driver selected equipment.

5.16.3TEST DATA RECORDING—Data sheet as presented in Figure 1 (Data Sheet 1) should be utilized but not

limited for recording the following data:

a.b.c.d.e.f.g.h.i.j.k.l.m.n.

6.6.16.1.1

Test date

Ambient temperature

Parking brake material description Parking brake lining material IBT

Loaded vehicle weight and identification of items/equipment making up the weight Unloaded weight, braked axle weight

Percent grade or grade angle and condition of gradeIndication of whether or not brakes were burnishedDirection of vehicle on the grade

Condition of driver selected equipment

Hydraulic brake school buses, record foot and/or hand control parking brake applied forceService brake application pressure or pedal force

Movement of vehicle that takes place after release of service brakes until vehicle becomes stationaryincluding wheel (s) roll or lock

Ability to hold vehicle stationary for 5 min including wheel(s) roll, lock or slide

Test Sequence

For vehicles with a parking brake system that does not utilize the service brakes:

Burnish parking brake in accordance with manufacturer's instructions to purchaser including recommendedvehicle weight. If no instructions are provided, no burnish is to be performed.

Adjust the parking brake and its actuation system in accordance with the vehicle manufacturer'sspecifications.

6.1.2

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SAE SAE J360 Revised DEC2001

6.1.3

Conduct unloaded vehicle test in accordance with 5.16, while limiting parking brake actuation forces to 556 N(125 lbf) for hand-operated or 667 N (150 lbf) for foot-operated system.

Conduct loaded vehicle test in accordance with 5.16, while limiting parking brake actuation forces to 556 N(125 lbf) for hand-operated or 667 N (150 lbf) for foot-operated system.

For vehicles with a parking brake system that utilizes friction elements of the service brake system:Burnish the loaded vehicle as described in SAE J1626 section 11.

Adjust the parking brake and its actuation system in accordance with the vehicle manufacturer'sspecifications.

Conduct loaded vehicle test in accordance with 5.16.Conduct unloaded vehicle test in accordance with 5.16.Reporting of Performance

Vehicle parking performance shall be expressed as the amount and type of effort or pressure applied to theparking brake system required to lock the braked wheels and whether the vehicle holds or slides on the gradefor a vehicle weight, a percent grade or grade angle, and the condition of driver-selected equipment. Theapplied effort or pressure shall be the higher value with respect to up and down grade directions. If pertinent tothe parking performance, the items making up vehicle weight and their location should be reported.Notes

Marginal Indicia—The change bar (l) located in the left margin is for the convenience of the user in locatingareas where technical revisions have been made to the previous issue of the report. A (R) symbol to the left ofthe document title indicates a complete revision of the report.

6.1.4

6.26.2.16.2.2

6.2.36.2.47.7.1

8.8.1

PREPARED BY THE SAE TRUCK AND BUS BRAKE SYSTEMS SUBCOMMITTEE

OF THE SAE TRUCK AND BUS BRAKE COMMITTEE

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SAE SAE J360 Revised DEC2001

Rationale—This document has been updated in keeping with the five-year review process. The Brake

Systems Subcommittee has sanctioned the following changes:

a.b.c.

Where practicable, make the test procedures consistent with the parking brake test procedure ofSAE J1626, and drawbar pull test procedure of SAE J1729, and with Federal safety standards.Item 1—Metric units were incorporated as reflected in the accompanying documents.

Item 2—Significant changes incorporated include the correlation with SAE J1626 latest revisionsJune 1999 and data sheet attached.

Relationship of SAE Standard to ISO Standard—Not applicable.

Application—This SAE Recommended Practice establishes methods to determine grade parking

performance with respect to:

a.b.c.d.e.

Ability of the parking brake system to lock the braked wheels.

The vehicle holding or sliding on the grade, fully loaded or unloaded.Applied manual effort.

Unburnished or burnished brake lining friction conditions.Down and up grade directions.

Reference Section

SAE J293—Vehicle Grade Parking Performance Requirements

SAE J1626—Braking, Stability, and Control Performance Test Procedures for Air- and Hydraulic-Brake-Equipped Trucks, Truck-Tractors and BusesSAE J2115—Brake Performance and Wear Test Code Commercial Vehicle Inertia Dynamometer49 CFR 571.105—Brake Performance—Hydraulic Brake Systems49 CFR 571.121—Brake Performance—Air Brake Systems

Developed by the SAE Truck and Bus Brake Systems SubcommitteeSponsored by the SAE Truck and Bus Brake Committee