Checking and adjusting basic charging pressure (B235R)
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Checking and adjusting basic charging pressure (B235R)
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1.
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Remove the bypass pipe with valve.
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Note
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There is an O-ring where the bypass pipe is fastened to the turbocharger inlet pipe.
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2.
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Remove the exhaust manifold heat shield. The heat shield is fastened with a nut and two clips underneath.
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3.
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Remove the locking clip on the operating arm with circlip pliers, part no. 83 94 538.
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4.
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Grip the pushrod with pliers, part no. 83 94 066 or similar tool. Undo the lock nut with spanner, part no. 83 94 520 or equivalent.
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5.
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Hold the operating arm and detach the pushrod. Secure the arm. Otherwise, the operating arm may ”jump over”.
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6.
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Move the operating arm on the boost pressure control valve towards ”Closed” and adjust the end piece so that the pushrod fits easily on the operating arm pin.
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7.
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Detach the pushrod from the control arm pin. Turn the end piece clockwise approx. 2 turns so that a 2 mm tension is achieved. Hook on the pushrod to the operating arm pin. Fit the locking ring.
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8.
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Detach the hose from the diaphragm box.
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9.
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Connect pressure/vacuum pump, part no. 30 14 883, to the diaphragm box and pressure gauge, part no. 83 93 514.
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10.
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Carefully pump up pressure until the control rod moves to regulate the boost pressure.
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11.
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Just as the control rod starts to move, read off the pressure on the pressure gauge. It should be 0.45 bar (±0.03 bar).
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12.
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Shorten the rod if the pressure is too low until 0.45 bar is obtained.
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13.
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Undo the pushrod and apply Molykote 1000, part no. 30 20 971, or equivalent to the pin on the operating arm.
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14.
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Fit the pushrod and clip, grip the pushrod with a pair of adjustable pliers and lock the nut.
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15.
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Remove the pressure gauge and pump.
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16.
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Reconnect the hose to the diaphragm box.
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17.
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Fit the heat shield.
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18.
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Lubricate the O-ring with acid-free petroleum jelly and fit the bypass pipe.
Tightening torque: 8 Nm (5.9 lbf ft)
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