Caro type connections for hydraulic pumps

Caro / karo type elbow connections come as a set with three mounting bolts and a seal. As the name suggests, the mounting bolts are spaced in a diamond (caro) shape relative to the connection outlet. These connections are available with internal threads for the inch system and external threads for the metric system. Typical execution is galvanized steel. Upon special request, we also offer 316L stainless steel versions.

Caro flange connections for hydraulic pumps, a complete guide

Looking for reliable components for mounting pumps in power hydraulic systems? Caro (karo) type flange connections are one of the most popular and reliable solutions used in agricultural and construction machinery, as well as industrial equipment. Get to know the technical specifications of these components and learn how to properly select a Caro connection for your hydraulic pump.

What are Caro connections for hydraulic pumps?

Caro connections (often also written as karo connections) are specialized flange connections whose name comes from the specific, rhombic arrangement of the mounting holes. Unlike standard square or rectangular connections, the bolt holes in Caro-type models are offset from the outlet axis.

The most common are 3-bolt Caro connections, which perfectly fit aluminum bodies of gear pumps group 1 and group 2.

Why choose aluminum flange connections?

The Caro connections available in our range are manufactured from high-quality aluminum. This material is characterized by an excellent strength-to-weight ratio, great heat dissipation, and full corrosion resistance. Using a flange connection eliminates the risk of overloading and cracking the aluminum pump body while tightening hydraulic hoses.

How to choose a Caro elbow connection? Key parameters

To ensure a perfect fit and 100% system tightness, three main technical parameters should be analyzed before purchase:

1. Mounting hole spacing

This is the most important dimension, measured from the center to the center of adjacent mounting bolt holes. There are two most popular standards:

• Caro 30 (30 mm spacing): Usually dedicated to smaller hydraulic pumps (e.g., group 1).

• Caro 40 (40 mm spacing): Used in more efficient gear pumps (e.g., group 2).

2. Connection thread size (BSP)

All offered connections have internal inch threads of the BSP (British Standard Pipe) type, which facilitates their integration with standard crimped hydraulic hoses. The most common configurations are:

• 3/8" thread (in Caro 30 standard) – for smaller flows.

• 1/2" thread (in Caro 30 standard) – the most universal size for medium pressure.

• 3/4" thread (in Caro 40 standard) – ideal for suction lines and systems with high oil flow rates.

3. 90° angular design

The presented products are 90-degree elbow connections. They allow for the immediate discharge of the oil stream at a right angle directly at the pump. This is an indispensable solution in tight assembly spaces where the bending radius of a flexible hydraulic hose would prevent the use of a straight connection.

Caro connection set contents

When buying professional Caro flange connections at the Hydron store, you receive a complete assembly set ready for installation:

• Aluminum connection body with an ergonomic elbow shape.

• Mounting bolts (3 pieces) with a hardness class matched for high-pressure operation.

• Rubber O-ring (seal): Placed in a specially milled groove on the flange surface. It provides excellent tightness at the connection with the pump without the need for Teflon tapes or sealing adhesives.

Expert advice: When installing the Caro connection, make sure that the rubber O-ring sits perfectly in its groove and that the bolts are tightened evenly (in a cross pattern) to avoid skewing the flange and to ensure even compression of the seal.

Application of Caro-type connections

Caro flange connections are widely used wherever connection reliability and compact dimensions matter. You will find them, among others, in:

• Tractors and agricultural machinery (steering assistance systems, three-point hitch).

• Mini-excavators, loaders, and road machinery.

• Stationary aggregates and hydraulic power units.

Choose proven Caro connections for hydraulic pumps and ensure the trouble-free, safe operation of your hydraulic system!

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