Seals (Preformed Packings and O-rings) and Gaskets [CFMB]

TASK 70-21-00-918-002-A
Seals (Preformed Packings and O-rings) and Gaskets

1. Reason for the Job
The data in this procedure is applicable to all installations that use seals or gaskets.
Seal removal, installation and lubrication instructions is given in this procedure.
This procedure tells you when you can continue to use a gasket.
2. Job Set-up
Subtask 70-21-00-869-051-A ** ON A/C NOT FOR ALL

A. Not Applicable.

3. Procedure
Subtask 70-21-00-020-051-A ** ON A/C NOT FOR ALL

A. Removal of the seal.
(1) Do not remove the seals with a sharp or pointed tool (knife-blade or a scriber) which could can cause damage to the surface of the parts.

Subtask 70-21-00-640-051-A ** ON A/C NOT FOR ALL

B. Lubrication of the seal.
(1) Lubricate the seals with lubricants recommended in the installation procedure.
(2) Apply a light layer of engine oil to the O-rings.
(a) If you apply too much lubricant, you can prevent the correct seal installation and can cause contamination.

Subtask 70-21-00-420-051-A ** ON A/C NOT FOR ALL

C. Installation of the seal.
(1) Use only new seals and rubber items during installation operations.
(2) Make sure the seals are in good condition and free from cuts or gouges.
(3) During the seal installation, be carefull to install the seal correctly.
(a) Make sure the seal groove (recess) is free from sharp edges.
(4) For O-rings that must be installed over threads or splines, you must use a conical sleeve, without burrs or sharp edges, to prevent damage to seal.

Subtask 70-21-00-210-051-A ** ON A/C NOT FOR ALL

D. Continued use of the gaskets.
(1) Examine the gaskets with imbedded flexible seal material for the limits that follow:
(a) Examine for nicks, cuts, gouges or openings across the surface of the seal material.
1 These are not permitted.
(b) Examine for hard or britted seal material.
1 These are not permitted.
(c) Examine the surface of the seal material for deformation that could cause a blockage of the seal.
1 These are not permitted.
(d) Examine the full length of the seal surface.

Subtask 70-21-00-918-051-A ** ON A/C NOT FOR ALL

E. Maintenance of the aluminium gaskets.
(1) Remove the lifted metal in the bolt hole area with a fine polishing stone or equivalent.
(a) Be careful not to cause damage to the seal material.
(2) Cut all thin, lacy, seal material that extends beyond the normal seal material on the aluminium surfaces.
(a) Be careful not to cut or loosen the bottom of the material.

[Rev.10 from 2021] 2026.04.01 12:53:49 UTC