The vacuum required to operate the brake booster is generated by a vacuum pump driven from the front end of the engine camshaft
This is because a turbocharged diesel engine does not have a vacuum in the intake pipe, which is used to operate the vacuum booster on vehicles with gasoline engines.
The cylinder head has a straight splined connection between the camshaft and the vacuum pump drive.
The operation of the vacuum pump does not require synchronization with the operation of the engine.
The vacuum is created by a blade fixed on the pump rotor.
The rotor is located in the pump casing and is connected to the pump shaft.
The lubricant is supplied to the pump under pressure through an oil channel in the cylinder head.
The lubricating oil is drained through the bottom of the pump into the crankcase.
To prevent oil from getting into the vacuum pipelines of the vehicle, a shut-off ball is installed in the vacuum connection of the pump.
The pump is designed to maintain a minimum pressure of 45 kPa at idle speed.
The vacuum pump, vacuum reservoir and brake booster are connected via hoses.
The vacuum reservoir increases the volumetric performance of the system.
Reasons why we replace the vacuum pump:
- the vacuum pump drive is damaged, the vacuum pump is worn out or damaged.
To check the vacuum pump, disconnect the vacuum pump hose.
Connect a pressure / vacuum gauge (part number 3164491) to the vacuum connection on the pump.
Start the engine. Let the engine idle for 1 minute to create the required vacuum in the system.
The vacuum gauge must be designed to measure a pressure of at least -45 kPa in order to be able to judge the operation of the pump.
If this minimum vacuum level cannot be reached, the vacuum pump must be replaced.
The design of the vacuum pump is rather complicated, special tools and equipment are required to repair it, therefore, if the pump fails, replace it as an assembly.
Loosen the hose clamp to the vacuum pump fitting
Disconnect the hose from the pump
We unscrew the rear bolt securing the vacuum pump
We unscrew the two front bolts securing the vacuum pump to the cylinder head
Removing the pump
Removing the gasket
Install the pump in reverse order.