TM 5-3805-260-24BRAKE SYSTEM TESTCheck of OperationThe stroke indicator (1) will give an indication whenbrake repair is needed. With the brake pedal pusheddown, make note of the stroke of the rod (1) on eachmaster cylinder. Brake repair is needed when, thestroke indicator moves more than 1.00 in. (25.4 mm)from the air chamber of the master cylinder.MASTER CYLINDER1. Stroke indicator.1.Start the diesel engine and let the air pressure inthe reservoir go up to cutout pressure.2.Push the brake pedal down and keep it in thatposition.3.Look at the stroke indicator.a.Slow movement of the stroke indicator afterit has stopped once, is an indication thatthere is leakage in the hydraulic section ofthe brake system or that the cup is cut.b.Extra travel of the stroke indicator (withbrake linings in contact with discs) is anindication that air is in the hydraulic sectionof the system.4.Release the brake pedal.a.if either one or both of the stroke indicatorsdo not retract, this is an indication that abypass opening in one of the mastercylinders is closed by dirt, corrosion or theprimary cup has become too large.NOTE: A primary cup which has become too large is anindication of wrong or dirty hydraulic fluid in the system. Ifhydraulic fluid is dirty, remove and repair all componentsin the hydraulic system of the brakes. Flush the brakelines with clean hydraulic fluid.Check for Leakage1.Push brake pedal down and keep it in thatposition.2.Put soap suds on the connections of the air linesat the master cylinders and check for airleakage.3.Release the pedal.4.Put soap suds on the exhaust openings of thecontrol valve for the brakes.5.When the pedal is pushed down, leakage mustnot be more than a 1.00 in. (25.4 mm) soapbubble in one minute.6.Repair any air leaks that are found.HYDRAULIC BRAKE SYSTEMSERVICINGUse heavy duty hydraulic brake fluids meetingSAE J1703C specifications only. Other fluids may causedamage to rubber parts.Do not let dirt or other material get in the brakefluid when the hydraulic brake system is serviced. Mostparts cleaners may be used to clean master cylindersand wheel cylinders if the parts are then thoroughlywashed with denatured alcohol or brake fluid to removeall of the solvent. After removal of the solvent, dry partsand protect from dust until cylinders are reassembled.Wash the rubber parts in clean denatured alcohol orbrake fluid.CAUTIONDo not use mineral base cleaning solvent such asgasoline, kerosene, distillant, carbon tetrachloride,acetone, paint thinner, etc. These solvents willdamage rubber parts and cause them to become softand of no use.2-153
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
