The valve cover is designed like a round plate that is clamped in the middle. It can be quickly removed due to a special thread construction. Valve covers, valve seats with cylindrical fit, as well as bushes (hubs) are tightened with rubber O-rings. The valve covers are fixed with special trapezoidal screws threads. They are tightened with firm rubber cuffs. Valve covers close the valves hermetically due to the tightening rings, located in each cover`s recess.

Sniffing valve covers are provided with hydraulic or mechanical clamps. Valve covers are made from carbonic steel casting and fixed onto hydraulic boxes in order to ensure a quick piston change on the coarse thread or on six to ten studs and are tightened with a rubber ring. Cover valves have a ridge. By examination of valve covers, valves and pistons it was determined that they got covered with a thick layer of carbon deposit and emitted a burning oil smell.

In order to fix that, you must remove the valve cover and file down one millimeter from the damaged valve sealing. But doing this without using special facilities will never ensure a proper and tight piston fitting. Therefore you need to grind out a perforated metallic ring that ensures a slip fit into the piston`s bottom. After that, you must fix the ring on a flat file, fit into the orifice the piston with down oriented sealant, and insert a conical three-edge scraper into the opening on the opposite side of the piston and remove the damaged piston surface with pressing rotating motions.

Before installing cover valves, you must remove dirt and old gasket remains from the housing and cover surface.