Pump Parts & Kits
ARO Diaphragm Pump Parts and Repair Kits
Genuine ARO pump parts for air operated double diaphragm pumps from 1/2" to 3", covering the Classic, Compact, PRO and EXP (Expert) series. This page carries air section and fluid section service kits, single replacement diaphragms, an air line connection kit and a wall mount bracket. For any diaphragm pump repair, the kit that matches the full model number puts back the same ball and diaphragm materials the pump was specified with, so it keeps the chemical compatibility it was chosen for.
ARO Parts by Pump Series
Every service kit on this page, grouped by the pump series it fits. Confirm the kit against the parts list for your full model number before ordering.
| Pump series | Air section kits | Fluid section kits (balls / diaphragms) |
|---|---|---|
Classic 1/2" 66605X non-metallic pumps |
637141 all 66605X models, and PD05P pumps without the -B suffix |
637140-EB Santoprene 637140-22 Nitrile 637140-88 Polyurethane, for abrasive media 637140-44 PTFE 637140-D2 Buna-N diaphragms and duckbill valves, for -0D2 models |
Compact 1/2" and 3/4" PD and PE models, including PD05 pumps ending in -B |
637428 Compact Series, including selected PD05P and PD05R 637389 Compact Series |
637427-AA Santoprene, PD / PE 637427-TT PTFE, PD / PE 637391-TT PTFE, Compact / EXP |
PRO Series 1" to 3" metallic and non-metallic |
637118-C PRO Series 637434 2" and 3" PRO and Specialty Series |
1" metallic 637119-EB-C Santoprene 637119-62-C Nitrile 637119-44-C PTFE 1" non-metallic 637161-EB-C Santoprene 637161-44-C PTFE 1" 637165-44 PTFE 1-1/2" 637124-EB Santoprene 637124-44 PTFE |
EXP (Expert) Series 1" to 3" metallic and non-metallic |
637397 1" metallic 637421 EXP metallic, including selected PD20, PD30, PE20, PE30, PF20, PM20, PM30 and PP20 637369 3" 637374-2 air valve kit, 2" and 3" |
1" 637401-TT PTFE, metallic 637396-TT PTFE, non-metallic 1-1/2" 637375-TT PTFE, metallic (PM15) 2" 637309-AA Santoprene, PD / PE / PM / PP 637309-AAA Santoprene with valve seats, metallic 637309-TT PTFE, including PD20A 637309-TL long-life PTFE 637373-TT PTFE, non-metallic 3" 637303-AA Santoprene 637303-TT PTFE, including selected PD30A |
Replacement Diaphragms and Accessories
- Single diaphragms 94617 white PTFE, 94355-T PTFE for Expert Series pumps, 94329-A Santoprene for 2" Expert Series pumps and 94091-A Santoprene for 3" pumps.
- Air line connection 66073-1 with hose, filter regulator and fittings (contents may vary) for 1/4" and 1/2" ARO pumps, including 66605X, PD05P and PD05R.
- Wall mount bracket 76763 mounts a 1/2" ARO diaphragm pump on a wall for a compact, centralized transfer station.
How to Find the Right Diaphragm Pump Rebuild Kit
A diaphragm pump rebuild kit is matched to the full model number on the pump nameplate, not to the pump size alone. Two pumps with the same port size can take different kits.
- 66605X air section 637141 for every 66605X model, whatever its wetted materials.
- 66605X fluid section 637140 plus the last two characters of the model, which code the ball and diaphragm. 66605J-3EB takes 637140-EB, 666053-344 takes 637140-44, 666053-322 takes 637140-22. Duckbill models such as 666053-0D2 and 66605J-0D2 take 637140-D2.
- PD05 pumps ending in -B 637428 air section kit and 637427 fluid kits, matched the same way: PD05P-ARS-PAA-B takes 637427-AA.
- PRO and EXP pumps Take the air and fluid kit numbers from the parts list in the operator's manual for your model. Material suffixes follow different conventions between series (Santoprene is -EB-C on 1" PRO kits and -AA on EXP kits), so do not convert a kit number from another pump.
- Valve seats Most fluid kits cover balls, diaphragms, O-rings and seals. 637309-AAA includes valve seats; 637401-TT and 637396-TT do not, so inspect the seats before reuse.
Groundable acetal pumps
For the groundable acetal 666056 and 66605H pumps, the operator's manual lists different O-rings in the PTFE fluid section kit than for the polypropylene versions. Check the parts list in the manual, available from the ARO Download Center, or contact ARO before ordering.
ARO Diaphragm Pump Troubleshooting
The symptom usually tells you which half of the pump to open. The checks below come from ARO's troubleshooting guidance for its 1/2" pumps; part names vary by series, so follow the manual for your model.
- Fluid at the air exhaust A ruptured diaphragm lets fluid through to the air side and out of the muffler. Replace the diaphragms with the fluid section kit. When pumping hazardous or flammable fluids, ARO advises piping the exhaust to a safe remote location.
- Air blowing out when stalled Air escaping from the main exhaust while the pump is stalled points to wear in the air section, such as the spool U-cups, valve plate or insert. Start with the air section kit.
- Fast or erratic cycling Check the piston O-rings in the air section for wear.
- Air bubbles in the discharge Usually a suction leak. Check the suction connections and the O-rings between the inlet manifold and fluid caps before rebuilding.
- Low output volume Rule out the air supply, a plugged outlet hose and leaks at the intake joints first. Check valves that stick or seat poorly point to worn balls or seats, which the fluid section kit replaces.
Keep a kit on the shelf
ARO recommends keeping service records and including each pump in a preventive maintenance program. A matching diaphragm repair kit in stock turns a diaphragm failure into a short repair instead of a wait.
Frequently Asked Questions
What is the difference between an air section kit and a fluid section kit?
The air section kit services the air motor that drives the pump, the part that never touches the fluid. The fluid section kit replaces the wetted wear parts: the check balls, the diaphragms and the O-rings or seals, in the materials of your pump's configuration, usually with a lubricant for reassembly. ARO splits the kits this way so each section can be serviced on its own.
Should I buy a single diaphragm or a full diaphragm repair kit?
A fluid section repair kit replaces the diaphragms together with the check balls, O-rings and seals, so the whole wetted side is renewed in one service. The single diaphragms on this page suit a quick replacement when the rest of the fluid section has been inspected and is in good condition.
Why use genuine ARO parts?
ARO's operator's manuals call for genuine ARO replacement parts to assure a compatible pressure rating and the longest service life. A genuine kit matched to the model number also puts back the ball and diaphragm materials the pump was specified with.
What does the 66073-1 air line connection kit include?
Hose, a filter regulator and fittings to connect a 1/4" or 1/2" ARO diaphragm pump to the plant air supply, though the exact contents can vary by item. It is listed as an accessory on the data sheets for the 66605X, PD05P and PD05R pumps. The filter regulator matters: ARO's manuals call for the pump's air to be filtered to remove particles larger than 50 microns.
Keep Your ARO Pumps Running
Order the diaphragm pump parts above, or browse the ARO diaphragm pumps these kits fit. For the air side of the installation, see the piggyback filter regulators and the needle valves used to set pump speed. Operator's manuals with full parts lists are in the ARO Download Center.
Not sure which kit you need?
Send ARO the full model number from the pump nameplate. Monday to Friday, 08:00 am to 5:00 pm CST.