This page contains excerpts from PS Magazine (a monthly magazine published by the US Government for Army personnel involved in maintenance) which describe how to perform a necessary brake vent modification on M44-series 2.5-ton 6×6 trucks such as the M35 cargo trucks or my M109A3 shop van. I used to have a couple of pages with many PS Magazine excerpts with 2.5-ton and HMMWV tips, but they are no longer necessary now that you can download individual articles from 1988 on at the PS Magazine web site. I kept these particular excerpts here because the vent line modification was published in 1983, and is not yet available on the PS Magazine web site. It’s a very good idea to check the PS Magazine index for other articles which may apply to your truck. For example, there’s an article in issue 542 (January, 1998) which describes a necessary brake light switch modification which replaces the old hydraulic pressure actuated switch, which could blow out and leave you rolling without brakes!
|BrakeVentCheck.jpg||105k||PS 555 (Feb 99), p5||Checking for brake vent line modification|
|PS 364 (Mar 83), p18-20||Brake vent line modification|
Here are more detailed descriptions of the parts needed for the M44A2-series version of the modification. I have not performed this modification yet, so please comment if you find any mistakes.
|1||Copper tubing||4710-00-203-3172||3/8″ OD, 72″ long|
|2||Adapter||4730-00-336-9558||1/4″ NPT female to 3/8″ OD compression fitting|
|3||Bushing||4730-00-196-0930||1/4″ NPT male to 1/8″ NPT female|
|4||Breather||4820-00-726-4719||1/8″ NPT male threads, includes filter, I do not know if this includes a check valve|
|5||Screw||5305-00-145-8368||5/16″ self-tapping hex head, 3/4″ long|
|6||Clamp||5340-00-833-8476||rubber-covered, 0.406″ nominal ID|
|7||Tiedown strap||5975-00-133-8687||4.5″ black nylon cable tie|
|8||Adapter||4730-00-289-1930||1/8″ NPT male to 3/16″ OD 42° flare|
|9||Adapter||4730-00-289-1254||1/4″ NPT male to 3/8″ OD 42° flare|
|10||Reducing elbow||4730-00-278-4694||90° 1/4″ NPT female to 1/8″ NPT female|
|11||Nipple tube||4730-00-278-3213||1.1″ long 3/8″ OD copper w/ 24 TPI UNS threads on each end, 150 psi rating|