Pump Cam Disc 40x90x8mm

The cam disc is the central element of the pump drive mechanism. Seated eccentrically on the main shaft, it rotates and forces the reciprocating movement of the pistons via the cam roller bearing. The dimensions 40x90x8mm define the fit on the shaft – internal diameter 40mm, external diameter 90mm, thickness 8mm.

Application

Cam disc 40043 is installed on the main shaft of the Kranzle pump drive chamber. The eccentric shape of the disc converts the rotational movement of the shaft into reciprocating piston motion – each shaft revolution corresponds to one working cycle of each piston. Cam roller bearing 40040 is seated on the outer surface of the disc and transfers the drive forces to the piston heads. The 8mm thickness fits within the drive chamber space and cooperates with spacer washers 40039 and 40041 operating in the same assembly.

Symptoms – When to Replace

• Uneven piston operation – differences in pressure or flow rate indicating an incorrect cam profile.
• Runout felt when rotating the shaft by hand after disassembly – the disc does not rotate evenly relative to the axis.
• Visible wear or pitting on the outer raceway surface – where the roller bearing operates.
• Disc play on the shaft – worn 40mm bore seat or damaged key that fixes the disc position.
• Knocking or irregular noise from the drive chamber that does not resolve after replacing the cam bearing.

How to Select the Correct Part

The basis for selection is reference number 40043. Before ordering, confirm the dimensions – the 40mm internal diameter must match the shaft journal, the 90mm external diameter defines the raceway for bearing 40040, and the 8mm thickness determines the axial positioning within the drive chamber. When replacing, compare the eccentric geometry with the removed disc – the shape and size of the eccentric determine piston stroke. If the disc was used with a failed bearing or contaminated oil, check the condition of the outer raceway before installing the new bearing.

Compatibility

Kranzle catalogue part. Used among others in Kranzle pressure washers with a pump featuring a cam drive system and a 40mm diameter shaft. Cooperates in the assembly with roller bearing 40040, cam washer 40039, and bearing washer 40041. Verify compatibility with a specific model using reference number 40043 or the pump service diagram.

[faq]

Can the cam disc wear out if the roller bearing was operating correctly?|Yes, although the bearing mediates contact and protects the disc raceway. Wear on the outer raceway of the disc occurs when oil is contaminated with metal particles, when the bearing operates with play, or after bearing seizure. In such cases, replacing the bearing alone is not sufficient – a disc with a damaged raceway will quickly destroy the new bearing.

How to determine whether play in the drive assembly originates from the cam disc rather than from the bearing or washers?|After disassembling the assembly, check the play on the shaft – the disc should sit without noticeable radial movement. Radial play of the disc on the shaft indicates a worn 40mm bore or a damaged key. Radial play between the disc and the bearing is a bearing problem, not a disc problem. The washers are responsible for axial play in the entire assembly, not for disc play on the shaft.

Would changing the disc thickness from 8mm to a different value affect pump operation?|Yes, directly. The 8mm disc thickness fits within the drive chamber space together with washers 40039 and 40041. A thicker or thinner disc will alter the axial positioning of the cam in the chamber and disrupt cooperation with the spacer components. The result may be excessive axial play or the inability to close the drive housing correctly.

Is the eccentric profile of the cam disc the same across all Kranzle pumps, or does it differ between models?|The eccentric profile and disc dimensions are matched to a specific pump – piston stroke, number of pistons, and their arrangement depend on the design of the given model. Disc 40043 with dimensions 40x90x8mm is a catalogue part for a specific pump series. Discs from other models must not be used on the basis of similar external dimensions without verifying the full set of dimensions and the reference number.

Is it necessary to adjust the pump setting after installing the cam disc?|The cam disc is an axially symmetrical component – its angular position on the shaft is fixed by the key and requires no additional angular adjustment. After installation, however, the axial play of the entire assembly should be verified, shaft rotation should be checked by hand before start-up, and the oil in the drive chamber should be topped up to the correct level.

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