AQ Pump head body - Flat

The AQ pump head body (flat version) is the base component of the AQ pump’s hydraulic section, carrying the working surfaces and seating zones of the water-system subassemblies. In service, it is replaced when the body is worn or damaged in a way that affects tightness and stability of operating parameters, and a rebuild limited to seals does not provide a lasting result.

MPN / reference: 40502
Version: flat

APPLICATION

The head body is used in typical AQ pump service work:

• repair of the pump’s hydraulic section when working surfaces are worn,
• pump overhaul when seats and sealing areas are worn out,
• eliminating recurring leaks caused by body damage,
• refurbishment of machines used intensively in workshop and industrial environments.

The “flat” version matters when identifying the body variant and matching it to the specific subassembly.

SYMPTOMS - WHEN IT’S WORTH REPLACING

Head-body replacement is most often considered when there are:

• recurring leaks despite seal replacement,
• unstable pressure resulting from worn seats or working surfaces,
• cracks, pitting, or deformation visible after disassembly,
• difficulty maintaining tightness after reassembly,
• accelerated seal wear when the base surfaces in the body are worn.

HOW TO CHOOSE THE RIGHT PART

Selection of a head body should be unambiguous:

• confirm pump type: AQ,
• verify the manufacturer number: MPN 40502,
• confirm the version: flat,
• compare body geometry with the removed part (channels, mounting points, seating zones),
• base selection on the pump/machine service documentation.

For housing/body parts, tolerances and geometry are critical - a similar-looking part may differ in details that prevent correct installation.

COMPATIBILITY

Select the head body based on MPN 40502 and compatibility with the specific AQ pump variant. Treat “flat” as an identifying feature of the variant that should be confirmed by comparing with the removed part and the service documentation.

[faq]

What does it mean in practice that the head body is “flat”?|It identifies a specific body variant and refers to its geometry. It matters for fitment, because different variants can have different seats and channels even if the general purpose is similar.

Can I swap the “flat” body for another AQ variant if the holes look similar?|Not recommended. Differences can be subtle (channels, seating zones), and the wrong variant can cause installation or sealing problems.

What marks on the old body most commonly qualify it for replacement?|Cracks, pitting, deep scratches on working surfaces, worn seats, and damaged sealing areas. Such defects typically lead to recurring leaks.

Will replacing the body fix the issue if valves or pistons are worn?|Not fully. Worn mating parts can still cause unstable operation and accelerate wear of the new body. In practice, the whole pump assembly is assessed.

What is critical at the first start-up after replacing the body?|Checking for leaks, pressure stability, and observing operation under load. Cleanliness of the system and water filtration are also important to avoid introducing contaminants that can quickly damage the new surfaces.

[/faq]