BRAKE INFORMATION FOR FKH AXLES S-CAM ROTATION ON DRUM BRAKE AXLES It is our recommendation (it is also a general industry recommendation) to install Drum Brake Axles so that the S-Cams rotate in the same direction (when the brake is applied) as the wheels when travelling forward, as illustrated below. WHEEL ROTATION S-CAM ROTATION FORWARD Failure to comply with this recommendation by having the S-Cam rotating against the direction of the wheels when travelling forward (reversed S-Cams) may result in noisy brakes, premature wear of the brake linings and premature wear of the tyres. Installers can rotate the axle in order to position the camshafts and boosters away from obstructions such as the trailer frame or suspension components, provided the S-Cam rotational direction is not affected and complies with the recommendation in this bulletin. www.khitch.com.au Uncontrolled document when printed! Bulletin No: KPM-008-0410 Rev4 1
INSTALLING THE BRAKE CHAMBERS (BOOSTER) The following information is for installing a FKH brand of double diaphragm spring brake chamber. 1. The FKH brake chamber is supplied with the push rod fully extended (NOT caged). 2. Depending on the brake force required (brake calculation), install the brake chamber in the appropriate bracket hole position. Nut torque 150-200lbft. Note: With the push rod fully extended and the brake chamber fitted to the correct mounting holes, the rod will line up with the correct hole in the slack adjuster, when the slack adjuster is at 90 to the push rod. 3. To cut the push rod to the correct length, start by marking the push rod in the fully extended position (no air applied / not caged) to the dimension in the table below. FKH Axle Model - axle tube size Booster rod cut length (mm) for slack adjuster setting of: 5 6 7 KF21/22 Ø 127mm 243 235 228 KF21/22 Ø 146mm 219 211 204 KF21 sq 127mm 232 224 217 KF37 Ø 127mm 196 188 181 KK44 Ø 127mm 173 165 N/A KF61/67/75/85-sq150mm 244 236 229 www.khitch.com.au Uncontrolled document when printed! Bulletin No: KPM-008-0410 Rev4 2
4. After the push rod is cut to the correct length, install the lock nut and clevis (as per photo ) and insert the clevis pin through the slack adjuster hole. 5. Now, follow the BRAKE ADJUSTMENT procedure on page 4. 6. To check the final installation; use the following table which contains the ideal dimensions with the booster and slack adjuster installed with the brakes applied. Axle Model and axle tube size Ideal booster to clevis pin dimension (mm) with brakes applied. KF21/22 Ø 127mm 246 KF21/22 Ø 146mm 222 KF21 sq 127mm 235 KF37 Ø 127mm 199 KK44 Ø 127mm 176 KF61/67/75/85-sq150mm 247 www.khitch.com.au Uncontrolled document when printed! Bulletin No: KPM-008-0410 Rev4 3
BRAKE ADJUSTMENT The following procedure must be followed after a new brake chamber or slack adjust has been installed or the brake needs adjusting for normal wear and tear: 1. Ensure that the correct specification brake actuator is fitted and that connection to the slack adjuster is in the correct position (refer to the trailer manufacturer s approved specification). 2. Make sure the trailer is on level ground, the wheels are chocked and the brakes are in the off position. 3. Adjust the free movement of the brake actuator push rod, tightening the slack adjuster to between 20-25 Nm torque. Then back off the adjusting screw by two notches (1/4 turn). Free play of between 6 and 10mm on the slack adjuster is usually sufficient to provide proper clearance. 4. By applying the brake, check the stroke of the brake chamber push-rod at the slack adjuster for movement of approx. 35 to 40mm. 5. At the full applied brake operating pressure (650 kpa) the angle between the push-rod and the slack adjuster needs to be at 90. www.khitch.com.au Uncontrolled document when printed! Bulletin No: KPM-008-0410 Rev4 4
15 AXLE SLACK ADJUSTER INSTALLATION The slack adjuster adapters are fitted to the 15 axle to avoid any contact between the push rod and the axle tube. Note: Type 24/30 Brake Actuators are shown for illustrative purpose only. Brake actuator size is variable and is dependent on a number of factors, i.e. number of axles, load weight, air brake kit, suspension type, tyre size, etc. The actual brake actuator size is determined by the brake calculation, normally carried out by the trailer builder. www.khitch.com.au Uncontrolled document when printed! Bulletin No: KPM-008-0410 Rev4 5