Allmand — Change O-ring of Auto-relief Valve and Vacuum Relief Valve
Repair & overhaul · Auto-relief valve / vacuum relief valve
From a Allmand service manual — check it applies to your exact model before use.
Before you start
- Use CALTEX MULTIFAK EP1 grease or equivalent. Grease of poor quality will deteriorate the material.
Procedure
- After disassembling and cleaning, check O-rings 1, 2 and 3.
- Replace any ring whose rubber is found hardened.
- Remove unloader cover and insert a wire through hole (2.5 drill) from inside to push out piston.
- Replace O-ring 6.
- Coat O-ring with grease slightly when reinstalling.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: Allmand service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.