AP Racing Catalogue Issue 4

visit www.apracing.com for installation drawings & up to date product range details 24 BRAKE CALIPERS - Technical Information & Replacement Caliper Seals basic dimensions The drawing below offers a brief explanation of basic AP Racing Drawing dimensions. Dim’n Descriptions PL Top of the pad material to mounting hole boss face, (hole centre-line on lug type calipers). C Offset - Disc centre line to centre of mounting hole (mounting face on lug type calipers) D Mounting hole centres. H Mounting hole diameters. E Disc width. U Wheel centre to cali- per mounting hole boss. (disc diameter / 2 - ‘Pl’ dimension). Spring Load. Piston ØF. Up to 34mm. Free Length & Wire Ø. (mm) Piston ØG. 34.9mm & above. Free Length & Wire Ø. (mm) 4lbs CP2632-113 38.43 & 0.91 CP2667-105 39.88 & 1.22 7lbs CP4100-121 39.88 & 1.02 CP2667-113 39.88 & 1.29 9lbs CP3432-134 49.02 & 1.02 CP2667-125 70.36 & 1.29 12lbs CP2632-129 58.50 & 1.29 CP2667-154 70.36 & 1.49 Anti-Knockback Spring Kits. Caliper Type Part Number Contents 4 Piston CP6518-4LBSS 4 x CP2632-113 CP6518-4LBLL 4 x CP2667-105 CP6518-7LBLL 4 x CP2667-113 CP6518-9LBLL 4 x CP2667-125 6 Piston CP6518-4LBSSL 4 x CP2632-113 & 2 x CP2667-105 CP6518-7LBSSL 4 x CP4100-121 & 2 x CP2667-113 CP6518-9LBSSL 4 x CP3432-134 & 2 x CP2667-125 ANTI-KNOCKBACK SPRINGS A range of anti-knockback springs are available for use with AP Racing calipers. The spring is located behind the piston in the caliper bore and is designed to counteract pad knock off. The springs are available in four loads indicated in lbs/f (force) with 2 sizes dependant upon piston diameter. RECOMMENDED TIGHTENING TORQUES AP Racing recommended tightening torques for the following products: ◘ M6 & ¼ UNF Pad Retaining Bolts: - 18Nm ◘ M4 Pad abutment cap head screws: (use loctite 242) - 3.5Nm ◘ M4 wear sensor clamp screw: (Use loctite 243) - 3.0Nm ◘ Cross pipe tube nuts: (Use loctite 648 inside tube nuts, with 7649 activator) - 24Nm FOR RACE CALIPERS ONLY. IMPORTANT NOTE - FOR ROAD CALIPERS CONTACT AP RACING TECHNICAL DEPARTMENT. ◘ 3/8”UNF Adaptors and Banjo bolts: - With one copper gasket: - 13Nm + 45° - With two copper gaskets: - 13Nm + 90° Resulting maximum torque must not exceed: - 30Nm ◘ CP6300 Dry Break Connector into caliper: - 13Nm (Loctite 270 can be used) ◘ Dry Break connector cap: - 4Nm ◘ Bleed Screws: - 17Nm DISC PATHWAY CLEARANCE Disc diameter clearance should be 2.5mm nominal from disc outside diameter to caliper pathway. The clearance can be reduced to 1.8mm minimum for smaller diameter discs (Ø280mm and lower). It is recommended that the tighter clearance is only used with radial mounted calipers where some degree of adjustment by using shims can be achieved if required. REPLACEMENT CALIPER SEALS Brake calipers are a safety critical item and AP Racing recommend that calipers are reconditioned and piston seals inspected regularly to maintain optimum perfor- mance. Where calipers have been subjected to high temperatures or have been used in adverse conditions e.g. Off Road / Rallying, the calipers should be recon- ditioned and seals replaced more frequently to ensure that safety and performance levels are maintained. When cleaning calipers use warm soapy water or an alcohol based cleaning fluid e.g. Methylated Spirits. DO NOT USE PETROL, GASOLINE OR MINERAL OIL CLEANER / LUBRICATE as this will damage the seals. Replacement seal kits are available for all AP Racing brake calipers. Depending on the seal type be- ing replaced the following recommended procedures should be followed. To find correct seal kit see page 26. CP4509 (Seal on piston) 1) Soak new seals in brake fluid for minimum of 30 minutes. 2) Clean brake caliper with warm soapy water and dry off. 3) With the pads removed insert a brake disc or block into the centre of the caliper. Using either hydraulic pressure or compressed air carefully extend all pistons against the disc or block. Remove block and remove pistons. Keep all body parts away from escaping air and caliper pistons. CAUTION: Your caliper is fitted with a Glyd Ring just inside the opening of each caliper bore. This ring should be examined and replaced if caliper has been subjected to high temperatures or used in adverse conditions e.g. Off Road / Rallying or not changed for a year. 4) Carefully remove old seals from piston with a narrow blunt edged tool. 5) Ensure that caliper bores, seal grooves and pistons are clean and free from debris and moisture. Use only Alcohol based cleaning fluid, not Mineral oil. 6) Carefully fit replacement seal into groove on piston ensuring that it seats correctly in the groove. Check seals are free from damage and correctly seated in groove not twisted or kinked. 7) Carefully engage piston into caliper bore and using a suitable rigid flat bar to apply even pressure, push pistons fully into body. N.B. Excessive force should not be necessary. If piston does not slide smoothly into bore remove & check seal has been fitted correctly. CP4518 & cp8518 (Seal in bore) 1) Soak new seals in brake fluid for minimum of 30 minutes. 2) Clean brake caliper with warm soapy water and dry off. 3) With the pads removed insert a brake disc or block into the centre of the caliper. Using either hydraulic pressure or compressed air carefully extend all pistons against the disc or block. Remove block and remove pistons. Keep all body parts away from escaping air and caliper pistons. 4) Carefully remove old seals with a narrow blunt edged tool. 5) Ensure that caliper bores, seal grooves and pistons are clean and free from debris and moisture. Use only Alcohol based cleaning fluid, not Mineral oil. 6) Carefully fit replacement seal into groove in caliper body ensuring that it seats correctly in the groove. Check seals are free from damage and correctly seated in groove not twisted or kinked. 7) Carefully engage piston into caliper bore and using a suitable rigid flat bar to apply even pressure, push pistons fully into body. N.B. Excessive force should not be necessary. If piston does not slide smoothly into bore remove & check seal has been fitted correctly. CP4519 (seal in bore with dirt seal) 1) Soak new pressure seals in brake fluid for minimum of 30 minutes. Do not soak dirt seals (double lip). 2) Clean brake caliper with warm soapy water and dry off. 3) With the pads removed insert a brake disc or block into the centre of the caliper. Using either hydraulic pressure or compressed air carefully extend all pistons against the disc or block. Remove block and remove pistons. Keep all body parts away from escaping air and caliper pistons. 4) Carefully remove both old seals with a narrow blunt edged tool.