Some of our replacement steering valve products have a valve in the pressure port that may or may not have been in your old steering valve.
This valve is called an inlet check valve and it’s only purpose is to allow flow in one direction only. Any reverse pressure spikes from momentary cylinder forces will cause the valve to close. This reduces the possibility of any kickbacks at the steering wheel and stops pressure surges to your hydraulic pump. In our image, we have two identical steering control units, SCU #1, and SCU #2. SCU # 1 has an check valve installed in the pressure port, SCU#2 shows the pressure port without a check valve.
Please note, some hydraulic inlet fittings have an integrated inlet check valve built in and it could cause problems to have two of these types of valves at the same time. In that case simply remove the inlet check valve from our unit. The inlet check valve is removable by unscrewing it from the port hole. The examples shown in the photograph use a T50 torx bit for removal.