These Lockheed kits include both the primary and secondary annular* seals. These kits fit the old Lockheed "tin can" style masters as well as newer AP Racing CP2623, CP4400, CP4623, CP5623, and CP6093 series master cylinders. The EPDM seals are formulated to work with any DOT-rated brake fluid (not for use with hydraulic oil).
Lockheed used the shape of the nose on the front of the master cylinder to identify bore sizes on the old "tin can" style master cylinders.
| AP Lockheed Master Cylinder Bore Sizes |
|---|
Front of
Master Cylinder | Nose Shape
Details | Bore Size | AP Kit No. | Part No. |
|---|
 | 0.25" Long Taper | 5/8" Bore | CP2623-90RK | 3514-.62 |
|---|
 | Shouldered Taper | 7/10" Bore | CP2623-91RK | 3514-.70 |
|---|
 | 0.50" Long Taper | 3/4" Bore | CP2623-92RK | 3514-.75 |
|---|
 | Groove | 7/8" Bore | CP2623-94RK | 3514-.87 |
|---|
* Annular seals have a hole for the piston to poke through. These kits do not include cup-type seals (without a hole). The pushrod dust seal may be plain style or bellows style as shown in photo.
Note: Not for AP CP6467/CP7198/CP9093 center-valve type, CP7854/CP7855/CP6465 rear-pivoting master cylinders, CP6461/CP6465/CP6468 pull-type, CP6026 hand brake type, CP5540 double-ended type, CP5898 differential-bore type, or any dual-circuit (two outlet) master cylinders. Does not fit any other brand.
