AQ Pump head body

The AQ pump head body is the main body of the pump’s hydraulic section, used in Kränzle pressure washers equipped with an AQ-type pump. It is the base component that carries the seats and working surfaces of the water system. In service, it is replaced when the body is worn or damaged in a way that affects sealing and stability of operating parameters, and “seal-only” repairs no longer provide a durable result.

MPN / reference: 405035

APPLICATION

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

• repair of the hydraulic section in systems with an AQ pump,
• pump overhaul when seats, working surfaces, or sealing areas are worn/damaged,
• eliminating recurring leaks caused by body wear,
• refurbishment of machines used intensively in workshop, service, and industrial applications.

According to intended use, the part is used among others in:

• Quadro 1000-1200
• Therm 895-1 / Therm 1165-1

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 and 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 405035,
• compare body geometry with the removed part (channels, mounting points, seating zones),
• base selection on the service documentation for the unit/pump.

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 405035 and compatibility with the AQ pump and the specific machine variant. The description indicates use for Quadro 1000-1200 and Therm 895-1 / 1165-1, but the safest confirmation is the parts list and comparison with the removed component.

[faq]

What’s the difference between a “head body” and a “complete head”?|The head body is the base hydraulic-section component (the body alone). A “complete head” typically means a more assembled unit/set with components already installed. In service, selection depends on whether only the body needs replacement or the entire assembled unit.

When does replacing the body make sense if the pump has already been resealed?|When leaks keep returning after several seal repairs and disassembly shows worn surfaces, pitting, or damaged seats in the body. In that case, new seals don’t have a stable base to work against.

Can one body fit both Quadro and Therm units?|It can, if the manufacturer specified the same AQ body variant for both families. The most reliable verification is MPN 405035 and comparing geometry to the removed part.

What most commonly “destroys” the head body in heavily used pumps?|Most often: deposits and contaminants in water, poor filtration, corrosion, overheating, or long-term operation that wears seats and working surfaces.

What should I check before reassembling the pump on a new body?|Condition of pistons/plungers, valves, guiding elements, and channel cleanliness. If mating parts are worn, they can quickly damage the new working surfaces in the body.

[/faq]