ID: nht75-3.33

DATE: 12/15/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Volvo of America Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Volvo of America's October 9, 1975, question whether a truck equipped with an air-assisted hydraulic brake system with hydraulic push through capability and, in the towing vehicle configuration, a source of compressed air for air braked trailer operation, is subject to Standard No. 121, Air Brake Systems.

From your description of the system and the materials that accompanied your letter, the truck does not qualify as an air-braked vehicle to which the standard applies. The fact that it is capable of operation in combination with an air-braked vehicle and supplies the compressed air for braking that vehicle does not affect the truck's classification as an hydraulic-braked vehicle.

At the time Standard No. 121 was developed, it covered virtually all of the trucks and truck-tractors in the heaviest categories. In planning and making your decisions to introduce hydraulic-braked vehicles in these weight categories, you should be aware that this agency is planning to cover all such vehicles with the basic performance requirements presently contained in Standard No. 121.

SINCERELY,

October 9, 1975

Frank Berndt, Acting Chief Counsel National Highway Traffic Safety Administration

Re: Applicability of Brake Regulations to Vehicle Combinations Consisting of a Hydraulic Brake Equipped Tractor and an Air Brake Equipped Trailer.

Volvo of America Corporation is currently considering the importation of a hydraulic brake equipped truck with a GVWR of 29,000 pounds. The basic vehicle can be outfitted as either a straight truck or a truck tractor. Both versions employ the same brake system. Our question concerns the applicability of the requirements of FMVSS No. 121 to this truck tractor when coupled to an air brake equipped trailer.

The operating principles of the brake system employed on both versions of the truck are described in the attachments to this letter. Basically it is an air assisted hydraulic brake system with a hydraulic push through capability. In the tractor version of this truck provisions are made in the brake system for the supply of compressed air to the brake system of the attached trailer. This is accomplished in a manner which enables the truck to operate in combination with conventional air brake equipped trailers.

Our understanding of the pertinent regulations indicates that since the truck tractor is not subject to the requirements of FMVSS No. 121, being fitted with hydraulic brakes, the combination of this tractor and an air brake equipped trailer also is not subject to the requirements of FMVSS No. 121, regardless of what requirements are applicable to the trailer by itself. Your verification of this understanding is requested.

Your prompt consideration of this matter would be greatly appreciated. If you have any questions concerning the technical details of the brake system, please direct them to Mr. Bjorn Klingenberg at the address indicated below:

Volvo of America Corporation Truck Division 266 UNION STREET NORTHVALE, N.J. 07647

All other communications concerning this matter should be directed to the undersigned.

VOLVO OF AMERICA CORPORATION Product Engineering and Development

Donald W. Taylor Manager, Product Safety & Quality

CC: B. KLINGENBERG

ID: nht75-3.34

DATE: 09/29/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Arent, Fox, Kintner, Plotkin & Kahn

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your September 23, 1975, request for confirmation that a manufacturer of air-braked buses that conform to Standard No. 121, Air Brake Systems, may direct owners of these vehicles to disconnect the antilock system used to meet the standard, for the period necessary to correct a safety-related defect in the system that may make its operation hazardous. Your concern is with S 108(a) (2) (A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S 1397(a) (2) (A)) that states:

S 1397 * * *

(2) (A) No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard * * *

Section 108(a) (2) (A) prohibits, with one exception, the knowing disconnection of the antilock system by a manufacturer, distributor, dealer, or motor vehicle repair business. This prohibition does not prevent an owner of air-braked buses from disconnection of the antilock system. The NHTSA has determined that a manufacturer of air-braked buses that conform to Standard No. 121 may instruct the owners of its products to disconnect the antilock system used to meet the standard, for the period necessary to correct a safety-related defect in the system that may make its operation hazardous.

A manufacturer that has determined the existence of a safety-related defect in his vehicle must, of course, comply with the Defect Report requirements of 49 CFR Part 573 and the Defect Notification requirements of 49 CFR Part 577.

SINCERELY,

ARENT, FOX, KINTNER, PLOTKIN & KAHN

September 23, 1975

Richard B. Dyson Office of the Chief Counsel National Highway Traffic Safety Admininstration

Pursuant to our telephone conversation of today, we are requesting your advice relative to a matter under the National Traffic & Motor Vehicle Safety Act. Our client, Rohr Industries, Flexible Division, manufactures buses on which are installed air brake systems which comply with 49 C.F.R. S 571.121 (Standard No. 121), skid control systems. Recently four Standard No. 121 systems which are manufactured by Rockwell International Corporation, have malperformed during the operation of a bus by a municipal customer of Rohr Industries. As the possible failure of the Standard No. 121 system presents a potential danger to the public, our client would like to take corrective action at the earliest possible time.

Rockwell International has indicated that a corrective device to prevent malfunctions in its Standard No. 121 system may be available for installation in November of 1975. It is our understanding that a manufacturer can, within the requirements of the National Traffic & Motor Vehicle Safety Act, direct its customers to disconnect the defective system until a correction to the system is available. It is requested that you confirm that our client, Rohr Industries, can in this situation, within the provisions of the National Traffic & Motor Vehicle Safety Act, direct its customers to disconnect the Standard No. 121 system until such time as Rockwell International has made available corrective equipment.

In order to implement this action which will remove a potentially unsafe situation, your confirmation is requested as soon as practicable. Your cooperation is greatly appreciated.

Joseph E. Casson

CC: FRANK FERRONE

ID: nht75-3.35

DATE: 09/03/75

FROM: AUTHOR UNAVAILABLE; W. T. Coleman, Jr.; NHTSA

TO: Hon. Bob Packwood - U.S. Senate

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of August 8, 1975, forwarding a copy of a letter to me from Mr. William G. White, President of Consolidated Freightways Corporation, and asking for early consideration of Mr. White's request. In that letter, Mr. White asks that the National Highway Traffic Safety Administration require reports from all truck operators and antilock system manufacturers on any malfunction they experience with antilock systems.

I have given full consideration to the important matter of collecting sufficient data on the reliability of antilock systems used on production vehicles, and I have responded to Mr. White with my conclusions. A copy of that response is enclosed to provide you with a complete explanation of my decision.

SINCERELY,

United States Senate COMMITTEE ON BANKING, HOUSING AND URBAN AFFAIRS

August 8, 1975

Honorable William T. Coleman, Jr. The Secretary of Transportation

I am attaching a copy of a letter from William White, Chairman of the Board of Consolidated Freightways, Inc. I am most interested in seeing that Mr. White's request is honored and would appreciate your early consideration of this matter. Could you please advise me of your ultimate decision.

As you may know, I have been following this matter regarding FMVSS 121 for some time. I have expressed my concern to the Administration over the hardships caused by this regulation and am awaiting their response at this time.

BOB PACKWOOD

cc: WILLIAM WHITE

CONSOLIDATED FREIGHTWAYS, INC.

July 31, 1975

Honorable William T. Coleman, Jr. The Secretary of Transportation

I attach copy of Dr. Gregory's letter to me of July 28th and my response to him.

I believe truck manufacturers, antiwheel lock device manufacturers and truck operators should be required by NHTSA to report any and all malfunctions of the antiwheel lock safety devices regardless of whether or not in their opinion the defect is safety related. All such reports should then find their way into the reliability file which has been set up in Room 5307, Motor Vehicle Programs, National Highway Traffic Safety Administration. NHTSA should not be allowed to screen such reports to determine whether or not they are "suitable for public scrutiny in light of applicable regulations and proprietary considerations".

Truck operators are now required to buy trucks with this equipment and are entitled to know exactly what problems are occurring in the field.

I will very much appreciate your looking into this matter.

WILLIAM G. WHITE -- CHAIRMAN OF THE BOARD

ID: nht75-3.36

DATE: 08/13/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Construction Machinery Company

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your June 18, 1975, question whether a system which pressurizes a water tank on a concrete mixer by means of air from the truck's air brake system would violate the requirements of Standard No. 121, Air brake systems.

The answer to your question is no. Standard No. 121 does not contain a prohibition on the use of air pressure from the air brake system for powering auxiliary devices. The vehicle must of course conform to Standard No. 121 following installation of the device if the installation occurs prior to the first purchase in good faith for purposes other than resale.

Although not a requirement of the standard, the National Highway Traffic Safety Administration does consider it appropriate that a pressure protection valve be placed in the line to the auxiliary device so that a rupture of an auxiliary line does not cause depletion of air pressure in the brake system.

SINCERELY,

June 18, 1975

T. Herlichy, Chief Counsel National Highway Traffic Division

I've talked to Mr. Williams about the method we use to take air from the air system of a truck to pressurize the water tanks on truck mounted concrete mixers. He in turn suggested I write you for an opinion whether or not the system comes under the brake regulation 121 and, if it does, whether we comply with it.

Basically the design is shown on Page 31, which is enclosed. Valves 4 & 5 on Page 31, are the same as the valves shown on Page 22. An air line runs from Valve 4 up to a control valve that allows the operator to add air to the water tank.

To give you a better idea of how the entire operation goes, let me describe the sequence of events when loading, mixing, and hauling concrete. First of all, the truck is driven under the batching plant at the ready mix yard and loaded with concrete. At the same time the driver fills the water tank with water. After the truck is loaded, it is driven out from under the plant to a mixing area where air is added to the water tank and the operator washes off whatever concrete that has accumulated on the mixer during charging. After the mixer is cleaned and the concrete is mixed, the truck is ready to go on the highway.

At this point no further air is taken from the truck system because either the water tank is completely pressurized or the operator will shut the air off to the water tank. So, while the truck is traveling from the ready mix plant to the job site, no air is taken from the truck brake system.

While on the job site the operator will add water to the mix and washdown the truck after the mixer is empty. He will again be taking air from the truck system. But before he returns to the highway either the water tank will be completely pressurized or the air shut off so that while he is traveling on the road no air will be used from the truck system.

I believe I have given you all the information needed, but if not, let me know what else is required and I will forward it to you.

CONSTRUCTION MACHINERY COMPANY

James E. Johnson, Chief Engineer Vice President-Director of Engineering

PRESSURE WATER SYSTEM

(Graphics omitted)

The air valves in the pressure water system are adjusted and set at the factory. Further adjustment should not be required except for possible adjustment of the height of dial as shown in illustration of leveling of water tank. The pressure regulator (1) is set to maintain a maximum pressure of 40 p.s.i. In the interest of safety this setting should not be exceeded. The relief valve (2) is set to crack open at 75 p.s.i. affording added protection for the system. Control valve (3) in the position shown, is admitting air to the tank, its normal operation position. Turning the valve handle 90 degrees clockwise shuts off the air supply and exhausts the air from the tank. When the air stops escaping, the water tank can be filled. Then moving the valve back to its original position will charge the tank with air. Valve (4) is a pressure hold-back valve. This valve prevents air from passing from the supply tank of the truck when the supply tank pressure is below 65 p.s.i. thus keeping pressure available for operating the truck brakes. Valve (5) is main shut off for all air to mixer water tank and controls.

To operate the pressure water system, open Valve "A". To add water to the drum, open Valve "C". To drain the entire system in freezing weather, open all valves "A", "B", "C", "D" and "F".

AIR SUPPLY TANK HOOK UP

HOOK INTO THE TRUCK AIR SUPPLY, USING THE METHOD SHOWN WHENEVER AIR IS TAKEN FROM THE TRUCK AIR SYSTEM FOR ANY MIXER CONTROL.

(Graphics omitted)

WATER TANK INSTALLATION (Illegible Data)

ID: nht75-3.37

DATE: 11/21/75

FROM: AUTHOR UNAVAILABLE; G.G. Mannella for James B. Gregory; NHTSA

TO: National Association of Motor Bus Owners

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letters of November 12 and 13, 1975, in which you requested that the National Highway Traffic Safety Administration immediately suspend the effectiveness of Standard No. 121, Air Brake Systems, with respect to buses, without waiting until the end of a comment period. In a notice published November 13, 1975, 40 FR 52856, this agency proposed such a suspension with a 30-day comment period ending December 15, 1975.

Secretary Coleman has made clear his commitment to allowing adequate time for public comment on rulemaking actions. The normal minimum time for public comment on Department of Transportation actions has been established as 45 days. In this case, because of the special urgency of the matter, the period was reduced to 30 days. I believe we all recognize that this action is a significant one, affecting the performance and cost of most of the transit and intercity buses in the country. In these circumstances, it is our judgment that the 30-day period is the minimum that can be justified for comment by the interested public, and your request is therefore denied.

We also recognize, as you have pointed out, that for this short period there may be some uncertainty and some interruption of normal activities within the affected industries. We will make every effort to reach and announce a decision as soon as possible after the end of the comment period.

Sincerely,

ATTACH.

NATIONAL ASSOCIATION OF MOTOR BUS OWNERS

November 13, 1975

Honorable James B. Gregory -- Administrator, National Highway Traffic Safety Administration, Department of Transportation

Dear Dr. Gregory:

This will supplement my letter of November 12, 1975, in regard to the problems created by failure to make effective immediately the suspension of Motor Vehicle Safety Standard No. 121 requirements respecting the brake anti-lock system on buses.

We understand why the National Highway Traffic Safety Administration does not want to deny any opponent of the proposed suspension an opportunity to be heard. Also, we are sure NHTSA does not want to halt sales of buses for six weeks or so, to disrupt bus manufacturing schedules, to cause temporary lay-offs of employees, or to require purchasers of buses to choose between taking immediate delivery of a needed bus or saving some $ 1,300.00 by postponing acceptance of delivery. These are the consequences of failure to make the suspension effective immediately.

We offer the following solution which, in our opinion, will fully protect the rights of any protestant of suspension if one should appear.

We suggest the suspension be made effective immediately, provided, the manufacturer and purchaser of any bus sold between now and January 1, 1976, agree in writing to the installation of the anti-skid device on or before January 8, 1976, if the National Highway Traffic Safety Administration concludes that suspension of the MVSS-121 requirement is unwarranted.

Since NAMBO members will be attending their Annual Meeting in Phoenix beginning Saturday, November 15, I am turning this matter over to NAMBO's General Counsel, Drew L. Carraway, Esq. of the firm of Rice, Carpenter and Carraway. Mr. Carraway will be in touch with your General Counsel's office to ascertain whether our proposal is satisfactory and advise those of us in Phoenix of your decision on this important matter.

Sincerely yours,

Charles A. Webb -- PRES.

cc: Frank A. Berndt (Acting Chief Counsel); Richard Dyson (Chief Counsel's Office)

NATIONAL ASSOCIATION OF MOTOR BUS OWNERS

November 12, 1975

Honorable James B. Gregory -- Administrator, National Highway Traffic Safety Administration, Department of Transportation

Dear Dr. Gregory:

ON November 11, 1975, the National Highway Traffic Safety Administration issued a proposed amendment of Motor Vehicle Safety Standard No. 121, Air Brake Systems, 49 CFR 571.121, to suspend, until January 1, 1977, service brake stopping distance requirements as they apply to buses.

In its tentative findings the Administration correctly noted that the present anti-lock system in buses is "characterized by malfunction that warrants its deactivation on all vehicles on which it is installed while a correction is fully developed" and that "a situation wherein purchasers of new buses are required to pay for anti-lock systems which are to remain deactivated for an indefinite period is inappropriate. NAMBO agrees with these findings.

The publication of this notice of proposed amendment of MVSS No. 121 creates a further problem for bus manufacturers since potential bus buyers will not purchase buses manufactured prior to whatever date the NHTSA may publish a final rule in the Federal Register due to the problems created by the anti-lock components as well as their cost.

Therefore, NAMBO urges the Administration to authorize the suspension of installation of potentially defective anti-lock components in buses pending a decision on the proposed amendment to MVSS No. 121.

The Annual Meeting of our Association begins on Sunday, November 16, in Phoenix, Arizona, at which time we will discuss and prepare a detailed explanation of the problems which would be created if the suspension cannot be made effective immediately. Our letter will be hand delivered to you on Thursday, November 20, with a copy to Mr. Richard Dyson of the Chief Counsel's Office.

Sincerely yours,

Charles A. Webb -- PRES.

cc: Richard Dyson

ID: nht75-3.38

DATE: 11/24/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Hon. J. P. Murtha - H.O.R.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your November 5, 1975, request for the criteria necessary for construction of testing equipment used to demonstrate compliance with Standard No. 121, Air Brake Systems.

The motor vehicle safety standards, including Standard No. 121, are established as requirements that vehicles must be capable of meeting if tested by the National Highway Traffic Safety Administration (NHTSA). However, the standards are not developed as demonstration procedures that detail methods a manufacturer would use to establish that its products comply. The development of actual test protocols to determine that products conform to the requirements is the responsibility of the regulated industry and the associated industries that service them.

Thus the Thiele Corporation, as a manufacturer of air-braked vehicles, may choose whatever test method gives it an adequate basis for certification that its products comply (15 U.S.C. @ 1397 (a)). Test equipment has been developed by several commercial sources, and Thiele can choose proper systems by consulting with the manufacturers of the brake components it uses. As for specifications for a test track, actual road tests are not necessary to establish compliance with Standard No. 121 where other reasonable means, such as engineering calculations coupled with laboratory tests, can be used to the same effect. Supplier warranties and instructions are one of the primary means by which smaller assemblers ascertain that their products conform.

Sincerely,

ATTACH.

CONGRESS OF THE UNITED STATES

House of Representatives

November 5, 1975

Richard B. Dyson, Chief Counsel -- National Highway Traffic Safety Administration

Dear Mr. Dyson:

Mr. William Wells of Thiele, Inc., a private truck building company, has requested that I inquire about the requirements for testing equipment under the Motor Vehicle Safety Standard 121 that went into effect in March of 1975.

Mr. Wells is interested in testing his own vehicles rather than bringing them to a professional testing track. Will you please inform me, in writing, what the criteria are for a company to build its own testing equipment in order to conform with the safety standards.

Thank you for your assistance in this matter.

Sincerely,

JOHN P. MURTHA -- Member of Congress

ID: nht75-3.39

DATE: 09/10/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Duo-matic Importers LTD.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Duo-matic's August 19, 1975, question whether Standard No. 121, Air Brake Systems, applies to an air brake coupler device that connects air brake hoses from a truck to the trailer it tows.

The answer to your question is no. Paragraph S3 (Applicability) of Standard No. 121 states that the standard applies to trucks, buses, and trailers equipped with air brake systems (with some stated exceptions). The standard therefore applies only to vehicles, and does not apply to motor vehicle equipment such as the Duo-matic coupler device.

SINCERELY,

August 19, 1975

Richard B. Dyson Assistant Chief Council Office of the Chief Council Federal Highway Administration

Refer to: A: Your letter N-40-30(MIS) dated 6-3-75

B: Motor Vehicle Safety Standard #121 as amended S5.3.3 Brake Actuation Time. With attached amendments of 11-12-74, 1-7-75, 1-17-75, 3-4-75, 3-21-75, 3-26-75, 5-15-75, and 6-11-75.

C: Duo-Matic Double Quick Release Coupling for Semi-Trailers (452-803)

D: Duo-Matic Double Quick Release Coupling for Towing Trailers (452 802)

The question is if Reference B above applies to our Wabco Westinghouse Duo-Matic coupler, which replaces the Glad Hand coupling now in use.

Your interpretation would be very much appreciated. We have enclosed two copies each of references C & D.

H. Melvin Strand, President

ID: nht75-3.4

DATE: 11/05/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: General Electric Company

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of July 8, 1975, to Ed Leysath of this agency concerning wattage requirements for Type 1A and 2A headlamps.

Your specific question is whether the wattage specifications in Federal Motor Vehicle Safety Standard No. 108 for Type 1A and 2A headlamps are design wattages or maximum wattages.

Paragraph S4.1.1.21(b) of Standard No. 108 specifies that, "Each Type 1A headlamp shall be designed for a maximum of 50 watts. Each Type 2A headlamp shall be designed for a maximum of 60 watts for each filament." (Emphasis added.) It follows, therefore, that the 50 - and 60-watt values are design wattages. You are correct in your interpretation that a tolerance of approximately 7.5% applies to these values, and that an ampere value of 4.20 for a 50-watt filament and 5.02 for a 60-watt filament is permitted. The 7.5% tolerance as you know is the average actual maximum wattage (as opposed to design wattage) rating of headlamps listed in Table 2 of SAE Standard J573 as determined by multiplication of the maximum amperage times the design volts.

Sincerely,

ATTACH.

GENERAL ELECTRIC COMPANY

July 8, 1975

Ed Leyseth -- National Highway Traffic Safety Administration, Department of Transportation

Subject: FMVSS 108 - Section 4.1.1.2.1

Dear Mr. Leyseth,

On March 26, 1975 I wrote to Bill Eason and requested an interpretation of the wattage requirements of the rectangular headlamp system. (copy enclosed). To date we have heard nothing and we urgently need your reply.

I would appreciate your help in providing us with your interpretation as quickly as possible.

Very truly yours,

Frank W. Bowers -- Manager, Product Reliability

attach: copy of 3/26/75 letter March 26, 1975

William Eason -- National Highway Safety Administration, Department of Transportation

Subject: FMVSS 108 - Section 4.1.1.21

Dear Mr. Eason:

I have heard that the Department of Transportation has interpreted Section 4.1.1.21(6) of FMVSS as far as the wattage limitation on Type 1A and Type 2A rectangular headlamps is concerned.

It is my understanding that the 50 watt limit on the Type 1A and the 60 watt limit on the 2A apply as design maximums and that a tolerance of approximate 7.5% applies to these values. This, then, would permit a max. ampere value of 4.20 for a 50 watt filament and 5.02 for a 60 watt filament. If a 40 watt filament is used than its max. amperes would be 3.36.

I agree with this interpretation and understand that these are the figures that SAE is proposing.

I would appreciate it very much if you would confirm that this interpretation is correct since design and certification of the product depends upon an accurate interpretation of the standard.

Thanks very much for your help in this matter.

Very truly yours,

F. W. Bowers -- Manager, Product Reliability

bcc: R. G. Burnor #1200

ID: nht75-3.40

DATE: 06/01/75 EST

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: Floyd, Kramer & Lambrecht

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your letter of April 25, 1975, concerning the applicability of Federal Motor Vehicle Safety Standard No. 106-74, Brake Hoses, to the Wabco Westinghouse Duo-Matic Coupler.

You have described the Coupler as a device which replaces the glad hand coupler now used by most manufacturers to connect truck tractor and trailer brake lines. Because the brake hose which attaches to the Coupler is equipped with its own end fittings, the Coupler itself is not an end fitting. Therefore, Standard No. 106-74 is inapplicable.

The Coupler is, however, subject to the requirements of 49 CFR Part 393.45 and 393.46, of which I have enclosed a copy. Please direct any questions you may have concerning interpretation of these requirements to the Office of the Chief Counsel, Federal Highway Administration, at 400 Seventh St., S.W., Washington, D.C. 20590.

YOURS TRULY,

DOUBLE QUICK-RELEASE COUPLING DUO-MATIC "SEMTRA" FOR SEMI-TRAILERS

DUO-MATIC "SEMTRA" is a compressed air brake coupling for fitting on semi-trailers.

* No possibility of confusing the lines when connecting up.

* Simple to fit with or without attaching plate.

* Cover closes automatically -- no lost covers.

* Valves placed in the hose part.

* Takes up little room.

Ordering example: 452 803 500 0 Trailer part and towing vehicle part.

452 805 000 0 Towing vehicle part

For other combinations, see table.

PATENTED TRAILER PART TOWING VEHICLE PART TRAILER PART ASSEMBLY NO. ASSEMBLY NO. TOWING VEHICLE PART ASSEMBLY NO. 452 803 000 0 452 805 000 0 452 803 500 0 [Graphics omitted]

TOWING VEHICLE PART 452 805 000 0 Item Qty Part No. Description 1 1 152 805 230 1 Hose connection 2 2 896 010 680 1 Valve spring 3 2 152 802 190 1 Valve cap 4 2 897 181 100 1 Cylinder seal 5 2 805 070 430 1 Dished washer 6 2 810 518 018 1 Locking ring 7 2 899 504 400 2 Valve assembly 8 1 452 801 650 1 Dust cover 9 1 896 200 710 1 Spring 10 1 892 222 200 1 Shaft

Part marked x are included in spare parts set. E Packenhen kompl. Best. no. 452 805 000 2

TRAILER PART 425 803 000 0 Item Qty Part No. Description 4 1 152 802 100 1 Bracket 5 2 152 803 230 4 Sleeve 6 2 891 500 451 1 Nut 7 2 895 110 750 4 Press ring 8 1 452 802 550 1 Bettom plate 9 1 452 802 610 1 Dog for cover 10 1 452 802 555 1 Upper cover 11 2 452 802 690 1 Shaft 12 4 895 222 330 1 Locking ring 13 4 152 802 710 1 Lever 14 1 152 802 553 1 Holding-down P.

15 1 800 200 700 1 [Illeg.] springs 16 1 896 010 690 1 Compr. spring

Part marked x are included in spare parts set. E Packehen kompl. Best. no. 152 803 000 2

FITTING OF DUO MATIC "SEMTRA" ON SEMI-TRAILER IN ACCORDANCE WITH AMERICAN METHODS

[Graphic omitted]

ID: nht75-3.41

DATE: 08/25/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: National Solid Wastes Management Association

TITLE: FMVSS INTERPRETATION

TEXT: This responds to the National Solid Wastes Management Association's July 29, 1975, question whether Standard No. 121, Air Brake Systems, or other Department of Transportation regulations require a vehicle operator to maintain and not disconnect brake components used in satisfaction of the standard. You state that you are already aware of operator responsibilities to meet the regulations of the Bureau of Motor Carrier Safety and those promulgated by State and local governments.

Section 108(a)(1)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. @ 1397(a)(1)(A)) specifies in part that no person shall sell or introduce in interstate commerce a vehicle which does not comply with applicable standards in effect on the date of manufacture. Section 108(b)(2) provides that @ 109(a)(1)(A) does not apply after the first purchase for purposes other than resale. The general effect of these provisions is that the brake system must comply and not be disconnected prior to its first retail sale. Section 108(a)(2)(A) provides that no manufacturer distributor, dealer, or motor vehicle repair business shall knowingly render inoperative a device installed in compliance with an applicable safety standard. Taken together, these provisions do not require the vehicle operator to maintain or not render inoperative a safety system after the first retail purchase. This agency does not recommend disconnection of elements of a brake system, however, in view of the probable adverse effect on handling not intended by the vehicle designer and engineer.

Other than the regulations of the Bureau of Motor Carrier Safety, of which you are aware, no regulations of the Department of Transportation require the maintainence or prohibit the disconnection of systems installed in satisfaction of motor vehicle safety standards.

SINCERELY,

National Solid Wastes Management Association

July 29, 1975

James Schultz Chief Counsel NHTSA

On March 1, 1975 FMVSS 121 Air Brake Systems became effective. It is our understanding that the vehicle manufacturer is responsible for complying with MVSS 121. Are there any requirements pursuant directly from MVSS 121 or indirectly from general applicability of DOT safety standards, which place responsibilities upon the vehicle operator to maintain or not to disconnect MVSS 121 equipment?

We are aware of the applicability of BMCS regulations upon interstate carriers and that often state legislatures and/or transportation departments often adopt Federal regulations and standards. However, clarification is desired pertaining to the implications of MVSS 121 on the vehicle operator, directly and indirectly.

James R. Greco Technical Director