Oil that turns milky, or spray mix showing up in the crankcase (or oil in the tank), means a diaphragm has torn. On an Annovi Reverberi (AR) piston-diaphragm pump, that’s the one failure you shouldn’t keep running through: spray mix in the crankcase destroys bearings and the crank.
1. Stop and drain
Shut the pump down as soon as you see milky oil. Drain the crankcase, and flush it with fresh oil until it comes out clean. Refill with AR crankcase oil (AR64532D); the Pump Finder lists how much your pump takes.
2. Replace all the diaphragms
Replace every diaphragm, not just the torn one. The others have the same hours and the same chemical exposure, and they’ll go next. AR sells a diaphragm kit for each pump with all of them.
3. Pick the diaphragm material
AR offers most kits in several materials. Match it to what you spray:
- Desmopan — a polyurethane diaphragm.
- NBR (Buna) — general purpose.
- BlueFlex — AR’s own diaphragm compound, standard on many current AR pumps.
- Viton — offered on some larger pumps for harsh chemicals.
Check your chemical labels or call us if you’re unsure; the wrong rubber will swell and fail early.
4. Valves and o-rings
If the diaphragms are good but pressure is down, surging, or the pump is slow to prime, the valves are worn or stuck. Pull them and look for debris, wear or broken springs, and replace them as a set with the valve kit. Replace the o-rings whenever you have the heads off; AR sells an o-ring kit for each pump. Weeping between the heads or manifold is o-rings.
5. Kits for common AR pumps
| Pump | Diaphragm kits | Valve kit |
|---|---|---|
| AR115BP / AR135BP | AR43251 BlueFlex, AR43249 Desmopan, AR43248 NBR | AR2370 |
| AR30 / AR40 | AR43285 BlueFlex, AR43283 Desmopan, AR43282 Buna | |
| AR1064 | BlueFlex, Desmopan, NBR and Viton kits |
AR has a lot of models and kits. Type your model in the Pump Finder and pick “Milky oil or spray mix in the crankcase”: it shows the diaphragm, valve and o-ring kits for that pump.
6. Pressure gauge jumping?
A gauge needle that pulses hard means the air chamber (accumulator) pre-charge is low or its diaphragm has failed. Set the pre-charge to the range in the pump manual for your working pressure.
Spray Center Electronics stocks pump parts and repair kits for Ace, Banjo, Hypro/SHURflo and Annovi Reverberi (AR) pumps in Spokane, WA. Part numbers here come from the manufacturers’ parts sheets; when your pump has been modified or the tag is gone, send a photo to sales@spraycenter.com or call (509) 838-2209 and we’ll match it before you order.