Haldex precharge pumps
The Haldex clutch is used in vehicles with four-wheel drive. It is located directly on the housing of the rear axle differential gear and mainly consists of a multi-disc clutch between the cardan shaft and the bevel gear of the axle gear. The system ensures optimum distribution of the engine power to the wheels of the non-driven axle. In most cases this is the rear axle. The Haldex preload pump is also part of this system.
How the Haldex preload pump works
The Haldex clutch controls the permanent four-wheel drive by continuously engaging the rear axle as soon as necessary. To do this, the Haldex precharge pump builds up a pressure that variably actuates the multi-plate clutch. The precharge pump thus switches the rear axle in addition to the front axle, which is driven anyway, as required. The Haldex clutch thus enables optimum control of the driving dynamics regulations, such as ESP (electronic stability program) and the electronic differential lock.
Let us illustrate the individual steps of the process with an example: Imagine you are driving your car over a road that is icy in some places.
1. shifting force to the rear axle
If the front axle now spins at such a point, the Haldex precharge pump reacts within milliseconds and allows power to be transferred to the rear axle. This is the axle that has more traction at that moment.
2. renewed power change on the axles
Once the front axle has passed the icy spot and the rear axle is now spinning at this point, the Haldex precharge pump takes the pressure from the vane clutch and thus interrupts the transmission of engine power to the rear axle.
In this way you always have total stability while driving and it is not so easy for the vehicle to break away.
We take care of your safety
By linking the Haldex system to key vehicle stability devices, the overall functionality should always be guaranteed. Repair the Haldex preload pump as soon as possible in the event of a failure.
We at Pixelfehler Hamburg offer you a wide range of Haldex precharge pumps for many different vehicle makes and models. When searching for the right spare part, please make sure that the OEM numbers of our Haldex precharge pumps and yours match. This is an article number that can be used to assign the spare part to a specific vehicle type.