Washer 4x9,9x1,2mm

In many pump connections, correct operation depends not only on the main working component, but also on a small assembly detail that determines pressure force, spacing, or the way parts fit together. The 4x9.9x1.2 mm brass washer works precisely in such points, where exact dimensions and repeatable seating are important.

APPLICATION

Washers of this size are used during repairs, assembly, and routine service work on pumps and other subassemblies of pressure equipment. Depending on the mounting point, they may serve to level the contact surface, transfer pressure force, reduce assembly play, or support connection sealing.

In service practice, such parts are replaced especially when, after disassembly of the system, the old washer is deformed, worn, or no longer maintains proper contact. In pump systems, even a small difference in thickness or diameter may change the way the assembly works, so washers should be treated as functional components, not merely auxiliary ones.

SYMPTOMS - WHEN IT IS WORTH REPLACING

• after disassembly of the connection, the washer is flattened or deformed
• the element does not sit evenly against the mounting surface
• play or incorrect pressure force appears at the fastening point
• visible dents, signs of wear, or mechanical damage are present
• after reassembly, the connection does not operate as stably as before

HOW TO CHOOSE THE CORRECT COMPONENT

When selecting such a washer, exact dimensions are decisive: inner diameter, outer diameter, and thickness. In this case, the 4x9.9x1.2 mm parameters must be confirmed and the part should be compared with the removed component. It is also important whether the washer works as a spacing, pressure, or sealing element, because this affects the installation requirements.

Before installation, it is worth checking:

• inner diameter 4 mm
• outer diameter 9.9 mm
• thickness 1.2 mm
• condition of the contact surfaces on both sides of the connection
• compatibility with the previously used part

Accurate selection is important in practice, because a washer that is too thin or too thick may change the position of cooperating components, reduce pressure force, or cause incorrect operation of the connection.

COMPATIBILITY

Compatibility of this part should be assessed primarily by its dimensions and the function it performs in the given pump assembly. The fact that a washer has a similar shape is not enough to confirm fitment. In practice, the diameter of the hole, the support surface, and the thickness matter, because they affect the final positioning of the fastened or seated components.

[faq]

Does the 4x9.9x1.2 mm washer serve only an auxiliary function?|Not always. In many connections, it is responsible for the correct spacing, even distribution of pressure force, or proper seating of components, so its dimensions directly affect operation of the assembly.

What does the 4x9.9x1.2 mm size mean?|These are, respectively, the inner diameter, outer diameter, and thickness of the washer. Each of these parameters must match the mounting point for the part to work correctly.

When is it worth replacing the washer with a new one?|Most often after disassembly, when flattening, deformation, dents are visible, or when the old part no longer provides proper pressure force and connection stability.

Can the brass washer be replaced with another one of a similar size?|Only if not only the dimensions match, but also the function of the part in the system. For assembly elements working in a pump, interchangeability should not be assumed solely on the basis of similar appearance.

How can I check whether the problem after assembly is caused by the washer?|It is worth looking for uneven pressure force, change in the position of cooperating parts, the appearance of play, or lack of proper contact at the connection point. These are typical signs that the washer size or condition is not correct.

[/faq]