You add a new distributor to your front loader (Tura), wrapper, or chipper. You connect the hoses, turn on the pump, pull the lever, and suddenly... you hear a loud crack, and oil spurts from the brand new distributor. The cast iron body has just cracked in half.
Why did this happen? In 90% of cases, the culprit is the lack of one small component: the pressure sleeve (pressure continuation) .
In this article, BRhydraulic experts explain what this inconspicuous threaded plug is for, when it's absolutely necessary, and how to properly install it in your system so as not to damage your machine.
1. Series connection and system pressure
To understand the role of the bushing, we need to look at how oil circulates within the machine. Very often, a single pump powers two distributors (e.g., the first from a Tura, and the second from the original linkage at the rear of the tractor). We call this a series connection .
Oil flows from the pump to the first distributor. If no lever is used in this distributor, the oil must flow further to the second distributor.
2. The Mistake That Costs Thousands: Powering from the "T" Port
Most novice installers pipe oil to the second manifold from the standard "T" (Tank/Return) return port of the first valve. This is a cardinal mistake!
The "T" port and the entire return gallery inside the cast iron distributor block are designed solely for the free flow of oil to the tank (pressure close to 0 bar) . The walls in this part of the valve are very thin. If you connect another distributor to the "T" port and attempt to lift a heavy load with it, you will create enormous pressure in the return channel of the first valve (e.g., 160-200 bar). The effect is immediate:
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Blown seals on sliders (leaks from under the lever).
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Swelling or complete rupture of the cast iron distributor body.
3. The Pressure Sleeve Comes Into Action (Port "N")
So how do we transfer high-pressure oil to the secondary distributor? This is done through the "N" (Power Beyond / Carryover) port and a pressure sleeve that screws into it.
The sleeve is simply a specially profiled steel extension with a seal (O-ring). When screwed into the "N" port, it mechanically plugs the internal channel in the manifold, separating the high-pressure gallery from the low-pressure (drain) gallery .
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Thanks to the sleeve (Port N): Full pressure oil from the pump flows safely to the second distributor through reinforced channels.
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Port T remains safe: It now serves solely to discharge "used" oil from the operating cylinders of the first distributor directly into the tank. No dangerous resistance is created there.
4. How to install a pressure sleeve? (Step by step)
Installation is very simple and takes just a few minutes:
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Locate the port marked N on your new manifold (often located right next to port T). This port is usually factory-sealed with a metal plug.
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Remove the plug from port N.
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Screw in the pressure sleeve that matches your manifold model (remember to use the appropriate thread, e.g. 1/2" or 3/4" BSP). Make sure the O-ring at the end of the sleeve penetrates deeply and seals the internal passage.
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Connect the supply hose of the second manifold to the newly screwed pressure sleeve.
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Important: The T-port of the first distributor must be connected directly to the oil tank with a separate hose!
Summary
A pressure sleeve is the cheapest insurance policy for your hydraulics. If you're connecting two valves in series on a machine (e.g., adding a joystick control ), its use is absolutely mandatory .
Please note that sleeves vary in threads and shape depending on the manufacturer and valve capacity (40 l/min, 80 l/min). In the BRhydraulic store you will find pressure sleeves and monoblock distributors Perfectly matched to your system. Complete a safe set today!