O-ring, 10 x 3 mm – Viton, Part# 23970305 – vacstellar

This little O-ring may look small, but it plays a big role in keeping your Leybold Trivac pump working right.

This one is made from Viton (also called FKM). That material handles hot pump oil, chemicals, and vacuum conditions much better than normal rubber. It lasts a long time and keeps seals tight.

You will find this exact 10 x 3 mm O-ring in many seal kits and major repair kits for the D40B, D65B, S40B, S65B, D40BCS and D65BCS pumps. Most kits include just one of these.

Replacing it is easy. Clean the groove, press the new ring in place, and put everything back together. One small change like this can stop a leak and bring your pump back to full performance.