Caution! Do not disconnect the check valve from the vacuum hose.
2. Check the operation of the check valve using a vacuum pump. The valve is OK if a vacuum is created and maintained when the pump is connected to the brake booster side of the valve, and no vacuum is created when the pump is connected to the intake manifold side of the valve.
Attention! If the check valve is faulty, it should be replaced together with the vacuum hose.
[The article is based on data from the website: www.MitsubishiMan.ru]