Oil-less recip pump rebuild
PTFE ring, cup, and bearing service on small oil-less reciprocating pumps.
This guide is general field reference for trained, qualified service technicians. It is not a substitute for the original equipment manufacturer's service manual, applicable codes (NEC, OSHA, ASME, local), or the judgment of a licensed professional. Procedures, torque values, pressures, refrigerants, and safety requirements vary by make, model, jurisdiction, and revision. Always verify against current OEM documentation and follow your employer's safety program. Working on compressed-air, electrical, pressure-vessel, and refrigerant systems can cause serious injury or death. By using this guide you accept all risk; AirCompDX and its authors disclaim all warranties and are not liable for any damage, injury, loss, or code violation arising from its use.
These pumps run hot — cool below 120°F before disassembly. PTFE dust is a respiratory irritant; wear a P100 mask during cleaning.
- Hex/Torx set
- Snap-ring pliers
- Torque wrench (in-lb)
- Calipers
- OEM PTFE/composite ring or cup kit
- Bearing kit (con-rod and main)
- Head gaskets / O-rings
- 1Document and disassemble
Photograph everything. Oil-less pumps use small fasteners in critical patterns — order matters.
- 2Pull head
Loosen in cross pattern. Inspect aluminum bore for scoring — black streaking is normal carbon, deep scoring = sleeve or replace pump.
- 3Remove piston/ring
Compress and pull the PTFE ring or cup off the piston. Measure thickness against OEM minimum spec.
- 4Bearing service
Press out con-rod and main bearings if logged hours warrant. Use sealed bearings of identical OEM spec — open bearings flood with PTFE dust and seize.
- 5Reassemble
Install new PTFE ring with the chamfer/scarf oriented per OEM. Torque head to in-lb spec in 3 passes.
- 6Run-in
Run unloaded 30 min — expect a brief odor as PTFE seats. Verify discharge temp settles and tank fill rate matches spec.