Sprayer Depot Blog

The Diaphragm Repair Kit (item # 870045) contains 3 diaphrams and 3 sets of O-rings (2 in each set). For this repair, you will need the following:

• Screwdriver

• Wrench

• 1/2" socket

• 11/16" socket

Follow these steps:

1. Loosen the bolts on one of the three head assemblies. 

2. Remove the head assembly, diaphragm nut, and washer.  Then, remove the diaphragm, sleeve and drain the internal oil.

3. Loosen the bolts on the second head assembly.  Remove the head assembly, diaphragm nut, and washer.  Then, remove the diaphragm and sleeve. Repeat this process on the remaing head.

4. Clean the inside of the pump with carb or brake cleaner.

5. Replace the sleeve, lining up the holes on the sleeve with the holes on the piston. Replace the diaphragm making sure the beveled side is pointed "out".

6. Replace the diaphram nut and washer. Use a wrench to make sure it's tight.

7. On each side of the three outer head assemblies, remove the inside of the valve cage.  Replace the spring, small seat (make sure to place the beveled side facing "down"), and large metal seat.

8. Place the valve assembly back on to the head and replace the O-ring with a new one.

9. The other side has the same pieces in the opposite order: Replace the spring, small seat and large seat. Replace the O-ring with a new one.  Repeat this process on all three head assemblies. 

10. Replace the head assemnbly and tighten the bolts in a clockwise pattern so they are evenly tightened.

11. Replace the piston sleeve on second side and replace the diaphragm with the beveled side facing "out". Replace the diaphragm washer and nut and tighten with a wrench.

12. Replace the second head assembly, tightening the bolts with a wrench. Using non-detergent, 40W pump oil , fill the open side of the pump to the brim.

13. Replace the final piston sleeve, lining up the holes with the piston. Clean off excess oil. 

14. Replace the final diaphragm.  Replace the diaphragm washer and nut. Tighten with a wrench. Replace the final head. (As on all of the head assemblies, there's a key which will not allow the head to go in the wrong way.) Tighten all bolts with a wrench.

15. Fill the oil resevoir to the oil level indicated on the side. Replace the cap on the reservoir. You're done!

Watch the Instructional Video Diaphragm Repair on a Udor KAPPA -43 Diaphragm Pump: