Cam 12,75

Cam 405231275 with an angle of 12.75° is a drive component of the Kranzle pressure washer pump. Mounted on the pump shaft, with a thrust bearing pack underneath it and the pump housing further down. The rotary motion of the motor turns the cam – its 12.75° angle generates the motion transferred through the bearing onto the pump pistons, converting shaft rotation into their reciprocating movement.

Application

The cam is mounted on the pump shaft. With each shaft rotation, the cam, set at a 12.75° angle, moves the pistons via the thrust bearing resting against its surface. The 12.75° angle determines piston stroke, and through that, the flow rate and pressure characteristics of the pump. The component operates within the bearing pack, which provides correct seating and axial clearance on the shaft.

Replaced during cam assembly repair – after identifying wear on the cam surface, damage to the thrust bearing, or as part of a comprehensive pump drive overhaul.

Symptoms – when to replace

• Vibration or irregular pump rhythm not caused by piston seals or valves – suggesting wear of the cam working surface or thrust bearing.
• Visible signs of seizure, scoring or dull wear marks at the contact surface between the cam and the bearing.
• Axial play on the shaft with the cam fitted – wear of the component at the mounting position.
• Damage to the thrust bearing of the bearing pack combined with signs of heating on the cam – bearing seizure frequently causes secondary damage to the cam surface.
• Replacement as part of the pack – if one component of the cam assembly shows wear after extended use, the remaining components are usually in a similar condition.

How to select the right part

The 12.75° angle is a relevant parameter, but not sufficient on its own for selection – pumps may have several cam variants with an identical angle, differing in drive type (electric vs combustion motor) or shaft mounting geometry. An identical angle does not guarantee interchangeability.

Identify by reference number 405231275. During disassembly, assess the condition of the bearing pack at the same time – these components work together and wear over a similar timeframe. If you are unsure about the pump drive type – verify on the disassembled machine or in the model documentation before ordering.

Compatibility

Drive component for the Kranzle AQ series pressure washer pump, cam angle 12.75°. Not a substitute for cams with other angles (9.5°, 10.8°, 12.0°) or for quadro/Profi series cams. Verify the exact compatibility range by reference number 405231275.

[faq]

The difference between 12.0° (40523120) and 12.75° (405231275) is small – does mixing up this one variant have a real impact on pump operation?|Yes, even though the numerical angle difference is small. Each degree of cam angle translates proportionally into piston stroke – even a 0.75° difference changes the pump's flow rate and pressure characteristic in a way that is detectable when measuring operating parameters. When selecting a cam, do not round the angle or treat neighbouring variants as practically equivalent – always confirm the angle on the removed component or in the model documentation.

How to identify the 12.75° angle on the cam without disassembling the entire bearing pack?|The angle marking is usually located on the side or front surface of the cam and may not be visible with the bearing fitted. When servicing an unknown pump for the first time, the only reliable method is disassembling the bearing pack and reading the marking on the cam. If you have the full pump or washer model number, the cam angle can be determined from the Kranzle parts catalogue for that model without disassembly.

How to identify early cam wear before noticeable pump vibration appears?|During disassembly of the bearing pack, examine the contact surface between the cam and the bearing in raking light – early wear appears as a dull, slightly uneven surface at the contact point, before visible scoring or wear marks develop. Also check whether the thrust bearing rotates evenly on the cam surface when turned by hand – resistance or grating indicates damage to one of these components.

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