Allmand — Pressure Compensated Orifice Cleaning
Repair & overhaul
From a Allmand service manual covering: M-250 Series, M-258, M-259, M-301, M-303, M-304, M-310, M-311, M-313, M-314, M-319, M-326…. Check it applies to your exact model before use.
Procedure
- If flow is blocked, inspect orifice hole for dirt.
- Blow compressed air through side holes to dislodge contamination.
- Push on inner piston with a blunt object and observe piston moving past side holes in housing.
- If sticky, remove push clip and disassemble.
- Clean with solvent and compressed air, oil parts, and reassemble.
- Do not use emery paper or steel wool to polish parts or touch orifice with pick or drill bit.
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.