AP Racing Catalogue Issue 4

63 visit www.apracing.com for installation drawings & up to date product range details MASTER CYLINDERS - General Information IMPORTANT NOTE:- AP Racing push type master cylinders are individually shimmed during assembly to minimise lost travel, therefore push rods, pistons and other internal components must never be switched between individual master cylinders. Note: This is to differentiate between push and pull type cylinders, pull type cylinders are not shimmed. Push Rod Part No. Length. Thread Form. Thread Length. CP2142-45 112.0mm 5/16” UNF 60.0mm CP2142-47 157.0mm 5/16” UNF 105.0mm CP2142-48 157.0mm M8x1.25 105.0mm NON CAPTIVE PUSH RODS Special versions of some master cylinders are available with ‘non captive’ push rods for use where rapid master cylinder changes may be required during an event (e.g. rally stages). Push rods to suit these master cylinders must be ordered separately under the following part numbers. ABS ADVISORY NOTICE WHEN USING AP RACING MASTER CYLINDERS Most AP Racing master cylinders use small cut-off ports to ensure that pressure is relieved from the brake system when no travel is applied to the brake pedal. As the brakes are applied the seal travels over this cut-off port. In normal operation the seal has travelled past this port before high pressure has built up in the system. However, when used in conjunction with ABS, depending on how the ABS operates, pressure can be built up earlier in the travel or during the return stroke. This can then result in heel nibble, where the seal is partially extruded up the cut-off port. The pulsing nature of ABS can also make this effect worse. It is possible to run AP Racing cylinders with ABS by allowing sufficient travel before pressure is built up and limiting the pressure during return, but as AP Racing do not control the ABS, we cannot guarantee successful operation. Typically, 6mm of travel will allow all seal sizes to be past the port and the maximum pressure up to this travel should be approximately 10bar. If this is exceeded the life of the seal will be compromised and re-sealing should be carried out more frequently. For ABS systems we recommend the use of one the following centre valve master cylinders CP6467, CP7198, CP7398 or CP9093. CENTRE VALVE MASTER CYLINDERS Some years ago AP Racing introduced a new range of centre valve high efficiency master cylinders. Those cylinders, CP6467, CP7198, CP9093 & now CP7398 types, feature a center valve configuration which helps to improve cylinder performance and seal durability with ABS. The centre valve replaces conventional ‘cut off’ ports that can cause ‘seal heel nibble’ when used with some ABS systems. CP6467 also features an optional system, (for which there is a patent pending) to greatly reduce ‘Knock Back’ events. This feature can be removed by substituting a sleeve for the AKB Plug. For further information please contact AP Racing technical department. ORDERING When ordering please quote the full part number whenever possible. Part numbers are given in the individual master cylinder pages. An explanation of the part numbers is given below. NB. For non captive push rod version add ’NC’ after bore size e.g. CP2623-90NCE CP2623-90PRM160E Master Cylinder Family Number Push Rod Thread Form (M8 x 1.25) Bore Size Ø15.9mm (5/8”) Push Rod Length 160mm (6.30”) ‘E’ Denotes Short Cut-Off Version IDENTIFICATION OF BORE SIZES All AP Racing master cylinders have their part number nominal bore size laser marked on the body, together with batch codes and serial numbers, to allow full manufacturing traceability. All master cylinders also have a coloured tie wrapped around the body for quick visual identification of bore size. Push Type Master Cylinders 14.0mm (0.551”) Black & Orange. 15.0mm (0.590”) Black & Red. 15.9mm ( 0.625”) 5/8” Black. 16.8mm (0.661”) Black & Yellow. 17.8mm (0.70”) Blue. 19.1mm (0.75”) 3/4” Green. 20.6mm (0.812”) 13/16” Orange. 22.2mm (0.875”) 7/8” Red. 23.8mm (0.937”) 15/16” White. 25.4mm (1.00”) Yellow. Pull Type Master Cylinders 14.9mm (0.587”) Black & Red. 16.2mm (0.638”) Black. 17.3mm (0.681”) Blue. 18.8mm (0.740”) Green. 20.2mm (0.795”) Orange. 21.2mm (0.834”) Orange & Red. 21.8mm (0.858”) Red. 22.4mm (0.882”) Red & White. 23.7mm (0.933”) White. 25.4mm (1.00”) Yellow.