Federal Motor Vehicle Safety Standards; Brake Hoses and Motor Vehicle Brake Fluids; Termination of Rulemaking

Topics:  National Highway Traffic Safety Administration, Federal Motor Vehicle Safety Standards

Barry Felrice
Federal Register
November 3, 1994

[Federal Register: November 3, 1994]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

 
Federal Motor Vehicle Safety Standards; Brake Hoses and Motor 
Vehicle Brake Fluids; Termination of Rulemaking

AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.

ACTION: Termination of rulemaking.

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SUMMARY: This document terminates a rulemaking proceeding that 
commenced in March 1985 when NHTSA granted a petition for rulemaking 
from the United States Army Tank-Automotive Command. The petition 
requested that NHTSA amend Standard No. 106, Brake Hoses, to require 
brake hose compatibility with a brake fluid with DOT 5 characteristics, 
and amend Standard No. 116, Motor Vehicle Brake Fluids, to require 
compatibility of DOT 3, DOT 4, and DOT 5 test fluids with elastomeric 
seals and cups in hydraulic brake system master and wheel cylinders. 
After receiving further information from the petitioner and after 
reviewing its own data base, NHTSA has concluded there is no safety 
need to amend the standards.

FOR FURTHER INFORMATION CONTACT: Mr. Chris Tinto, Office of Vehicle 
Safety Standards, National Highway Traffic Safety Administration, 400 
Seventh Street SW., Washington, D.C. 20590. Mr. Tinto's telephone 
number is (202) 366-5229.

SUPPLEMENTARY INFORMATION:

Background and Grant of Petition

    On March 20, 1985, NHTSA published a Federal Register document (50 
FR 11213) granting a petition for rulemaking submitted by the United 
States Army Tank-Automotive Command (ATAC), to amend Federal Motor 
Vehicle Safety Standards Nos. 106, Brake Hoses, and 116, Motor Vehicle 
Brake Fluids. The petitioner requested NHTSA to expand the number and 
type of ``referee materials'' used to test samples of brake hose 
(Standard No. 106) and brake fluid (Standard No. 116) for compliance 
with the requirements of those standards.
    Referee materials are used in the test procedures of Standards Nos. 
106 and 116 to represent typical fluids and components that are present 
in real-world brake systems. The referee materials are combined with 
the test sample of brake hose or fluid to determine the compatibility 
of the referee material and the test sample. At the time the petition 
was filed, Standard No. 106 referenced a referee material called RM-1 
SAE Compatibility Fluid to test hydraulic brake hose and hose 
assemblies.1 Standard No. 116 also referenced RM-1 SAE 
Compatibility Fluid to test samples of DOT 3, DOT 4, and DOT 5 brake 
fluid. In addition, Standard No. 116 referenced another referee 
material, ``SAE referee cups'' made of styrene butadiene rubber (SBR), 
to test the compatibility of test samples of DOT 3, DOT 4, and DOT 5 
brake fluid with the material. In all cases involving the use of 
referee materials, the referee materials are combined with the test 
sample of hose or fluid to see the effect of the combination. For 
example, in Standard No. 116's test evaluating the effect of brake 
fluid on cups (S5.1.12), the referee SBR cups are immersed in the test 
fluid, heated, then examined for disintegration, hardness changes and 
diametrical changes.
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    \1\In 1986, Standards No. 106 and 116 were amended to replace 
RM-1 SAE compatibility fluid with RM-66-03 fluid. (See 51 FR 16694.) 
In October 1992, NHTSA published a notice of proposed rulemaking to 
update the referee fluid to RM-66-04, effective January 1, 1995, as 
RM-66-03 is no longer readily available. (See 57 FR 49162.)
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    ATAC requested that Standard Nos. 106 and 116 be amended in two 
primary ways. First, the petitioner suggested that Standard No. 106 be 
amended to require brake hose compatibility with a fluid with DOT 5 
(silicone) brake fluid characteristics. ATAC stated that the U.S. Army 
adopted DOT 5 silicone brake fluid as its standard operating fluid for 
its motor vehicles with hydraulic brake systems. After replacing the 
brake fluid with DOT 5 fluid in some of its vehicles, the Army had 
operational problems with aftermarket procured hydraulic brake system 
components. The Army believed it had traced the problem to excessive 
swelling of elastomeric seals and cups within the hydraulic brake 
system master cylinder. The swelling appeared to be caused by 
incompatibility problems between the DOT 5 brake fluid and brake system 
components made of rubber. Since Standard No. 106 does not test brake 
hose and hose assemblies with a referee material brake fluid 
representing DOT 5 (silicone) fluid, ATAC suggested amending Standard 
No. 106 to require brake hose compatibility with a silicone fluid.
    Second, ATAC suggested that Standard No. 116 be amended to require 
that master and wheel cylinder cups made of ethylene propylene diene 
monomer rubber (EPDM) be compatible with a DOT 3, DOT 4 and DOT 5 brake 
fluid referee material, and to include specifications for these EPDM 
and other rubber components. The tests in Standard No. 116 that measure 
the effect of brake fluid with rubber are run with SAE referee material 
SBR cups only. ATAC believed that the aftermarket EPDM brake system 
components it encountered were incompatible with the DOT 5 brake fluid 
in its vehicles.
    The agency believed that the issues raised by ATAC warranted 
further consideration. Thus, NHTSA granted ATAC's petition.

Rationale for Termination

    Subsequent to its petition, ATAC provided further information to 
NHTSA indicating that its problem had been resolved. Tests conducted by 
the Army at Fort Belvoir, Virginia, implied that there was some 
confusion as to what actually caused the problem in the braking systems 
of the vehicles in question. Nevertheless, ATAC informed NHTSA that it 
solved its problem by using only military specification (MIL spec) 
brake components and brake fluid in ATAC vehicles. ATAC indicated that 
EPDM and SBR components that met the Army's MIL-C-14055, ``Cup, 
Hydraulic Brake Actuating Cylinder, Synthetic Rubber'' specification 
perform satisfactorily with silicone brake fluid. ATAC further 
indicated that if MIL spec MIL-C-14055 were used for parts procurement, 
it would avoid any problems of component deterioration in the future.
    NHTSA supplemented this information with data for non-military 
motor vehicles. NHTSA believed that if brake fluid compatibility 
problems similar to those experienced by ATAC were occurring in non-
military vehicles, the public would have reported some of these 
incidents to NHTSA's Auto Safety Hotline. The Hotline is a 
comprehensive database that encompasses over 250,000 consumer calls, 
dating back to 1981, relating to vehicle and component performance and 
complaints. Approximately 35,000 of these calls are about brake-related 
performance. NHTSA conducted a database search for all complaints 
relating to brake fluid in passenger cars, light trucks, buses and 
heavy trucks, and found no evidence of a safety problem. The agency 
found only 17 complaints that referred to ``brake fluid'' as the basis 
for the complaint. The majority of the complaints referred to 
contamination problems (water, fuel, and other fluid intrusion into the 
brake fluid).
    Moreover, approximately 8 of the 17 complaints concerned vehicles 
that had traveled fewer than 50,000 miles. Because of their relatively 
low mileage, NHTSA does not believe these vehicles had anything other 
than the original brake fluid in them. Given the preponderance of 
vehicles manufactured with DOT 3 fluid over vehicles manufactured with 
DOT 5 fluid, the agency believes the original brake fluid in the 
vehicles in question was DOT 3 fluid, not DOT 5 fluid. There was one 
complaint referring to a problem with ``silicone'' brake fluid and 
brake system components, involving an antique Jaguar car and a certain 
brand of silicone fluid. A single complaint in a database as 
encompassing as the Hotline complaint file does not indicate the 
possible existence of a significant safety problem.
    In conclusion, there is no evidence of a safety problem regarding 
the compatibility of silicone fluid and brake system components. NHTSA 
believes that if there were a safety problem with brake fluid and 
component compatibility, evidence of the problem would have appeared in 
the ten years since ATAC's petition was received by NHTSA. No such 
evidence has manifested. Accordingly, the agency is terminating this 
rulemaking action.

    Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166; 
delegation of authority at 49 CFR 1.50.

    Issued on: October 27, 1994.
Barry Felrice,
Associate Administrator for Rulemaking.
[FR Doc. 94-27261 Filed 11-2-94; 8:45 am]
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