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CP4509 - 'Seal on Piston' Replacement Seal Kits

CP4509 - 'Seal on Piston' Replacement Seal Kits

SKU:CP3724-139

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CP4509 - 'Seal on Piston' Replacement Seal Kits

Brake calipers are a safety-critical item and AP Racing recommends that calipers be reconditioned and piston seals inspected regularly to maintain optimum performance. Where calipers have been subjected to high temperatures or have been used in adverse conditions e.g. Off Road / Rallying, the calipers should be reconditioned 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 being replaced the following recommended procedures should be followed.

Fitting Instructions:

  1. Soak new seals in brake fluid for a minimum of 30 minutes.CP4509-Diagram
  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 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 the piston does not slide smoothly into bore remove & check seal has been fitted correctly.

Part Numbering

  • Two letters after Kit indicates 4 seals - e.g. -JJ

Bore Identication Letters:

 Bore Identification Letter Bore Diameter (mm) Bore Diameter (inch)
A 25.4mm 1.00"
B 26.0mm
C 27.0mm 1.06"
D 28.6mm 1.125"
E 31.8mm 1.25"
F 34.0mm
G 34.9mm 1.375"
H 36.0mm
J 38.1mm 1.50"
K 41.3mm 1.625"
L 44.5mm 1.75"
M 47.6mm 1.875
N 50.8mm 2.00"


Part Numbers:

 Caliper Bore Individual Seal Part Numbers Seal Kits

4 Piston Calipers
28.6mm & 34.9mm CP3724-138 & CP3724-135 CP4509-DG
31.8mm CP3724-137 CP4509-EE
31.8mm & 36.0mm CP3724-137 & CP3724-134
CP4509-EH
31.8mm & 38.1mm CP3724-137 & CP3724-133 CP4509-EJ
34.9mm & 41.3mm CP3724-135 & CP3724-132
CP4509-GK
Ø38.1mm CP3724-133 CP4509-JJ
Ø38.1 & Ø41.3mm CP3724-133 & CP3724-132 CP4509-JK
Ø38.1mm & Ø44.5mm CP3724-133 & CP3724-131 CP4509-JL
Ø41.3mm & Ø44.5mm CP3724-132 & CP3724-131 CP4509-KL

6 Piston Calipers
27.0mm & 31.8mm & 38.1mm CP3724-139 & CP3724-137 & CP3724-133 CP4509-CEJ
28.6mm & 31.8mm & 41.3mm CP3724-138 & CP3724-137 & CP3724-132 CP4509-DEK

 

Brand AP Racing
Options SKU Barcode
Single Seal / Ø27.0mm CP3724-139
Single Seal / Ø28.6mm CP3724-138
Single Seal / Ø31.8mm CP3724-137
Single Seal / Ø34.9mm CP3724-135
Single Seal / Ø36.0mm CP3724-134
Single Seal / Ø38.1mm CP3724-133
Single Seal / Ø41.3mm CP3724-132
Single Seal / Ø44.5mm CP3724-131
4 / Ø31.8mm CP4509-EE
4 / Ø38.1mm CP4509-JJ
4 / Ø28.6mm | Ø34.9mm CP4509-DG
4 / Ø31.8mm | Ø36.0mm CP4509-EH
4 / Ø31.8mm | Ø38.1mm CP4509-EJ
4 / Ø34.9mm | Ø41.3mm CP4509-GK
4 / Ø38.1mm | Ø41.3mm CP4509-JK
4 / Ø38.1mm | Ø44.5mm CP4509-JL
4 / Ø41.3mm | Ø44.5mm CP4509-KL
6 / Ø27.0mm | Ø31.8mm | Ø38.1mm CP4509-CEJ
6 / Ø28.6mm | Ø31.8mm | Ø41.3mm CP4509-DEK