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Replacing ABS Pump

ABS light

The anti-lock braking system (ABS) is an electronic control system that compresses the brakes in rapid sequence to prevent the wheels from locking up and sliding. They allow the driver's instinct to mash down hard on the brake pedal in an emergency to keep the tires from locking and skidding on the surface, causing the driver to lose control.

If you have an ABS light, you can find out how to diagnose the problem here before replacing parts that don't need replacing. If diagnostics indicate a pump is bad, here are the procedures for removal and replacement on most vehicles.

Remember: your car's braking system is its primary safety feature. Treat it as such.

Start by disconnecting the negative battery cable and then the connection to the ABS controller. Disconnect the brake lines from the ABS controller using a proper wrench, usually a flare wrench. Be very careful not to harm or strip the nuts. Plug the brake lines and remove the hydraulic control unit.

On most vehicles, the HCU is integral to the ABS controller. On some, they are separate and one may be removed and replaced without the other. This is not usually the case, so both must be replaced as a unit. Be sure the replacement you have is correct for your vehicle before plugging it in.

Once the new one is in place, attach the brake lines carefully and plug the electrical connector in. Bleed the brake system (find a how-to here). Reconnect the battery cables. The ABS light should no longer be on when you start the car.

Test the braking system thoroughly, making sure that the ABS light does not return.