Stiffening Washer, Leybold, Trivac, Part# 45174425 – vacstellar

This is a small, flat metal washer.

It goes right on top of the valve plate inside the exhaust valve of your Leybold Trivac pump – the D2A, D4A, D2AC, and D4AC models.

The valve plate itself is very thin. Without this stiffening washer, it can bend or warp after a while. When that happens, the seal gets weak, vacuum drops, and the pump gets noisy.

This washer keeps everything flat and strong. The spring pushes down on it, the plate seals perfectly, and the pump runs like it should.

You only need one per pump. It comes in every major repair kit (usually listed right next to the valve plate and spring).

It’s cheap, fits exactly, and most technicians throw it in whenever they open the pump head. Simple part, big difference.