7. Brake system

The hydraulic foot VW T4 brake system consists of the main brake cylinder, the amplifier of brakes and brakes of forward and back wheels. The emergency brake affects through a rope brake shoes of back wheels.

On forward wheels disk brakes which, depending on equipment, for the best heat removal are blown by air from within are established. Back wheels slow down automatically adjustable drum brakes.

The hydraulic brake system is divided into two contours working on diagonal. One brake contour works in front on the right, behind at the left. The second – in front at the left, behind on the right. Thanks to it, at breakage of one of contours, nevertheless one is braked forward and one, on diagonals, a back wheel. Thus the car can be stopped.

Pressure for both brake contours is created in the main brake cylinder when pressing a brake pedal. Over the main brake cylinder in a motor compartment the tank of brake fluid is located. The hydraulic drive of coupling is also supplied with brake fluid from this tank (in separate models the coupling drive however is carried out not hydraulically, and mechanically – through a coupling rope). At all models, at too low level of brake fluid the control bulb on a guard of devices lights up, but nevertheless the amount of brake fluid needs to be checked regularly.

On cars with the petrol engine there is a vacuum amplifier of brakes who when braking creates, due to discharge in the soaking-up engine pipe, the additional effort to a pusher of the piston of the main cylinder is proportional to effort from a pedal.

On diesel cars discharge is created at the expense of the special vacuum pump attached to the engine.

The regulator of brake efforts on the back bridge watches that at sharp braking there was no blocking of back wheels. Cars with anti-blocking system (ABS) or with the all-wheel drive have no regulator of brake efforts. Adjustment of brake efforts on back wheels is undertaken by the ABS control unit.

As additional equipment of VWT4 the anti-blocking system (ABS) is offered. The works described here concern all VW T4 models, with ABS or without it.

Depending on diameter of a wheel on forward wheels various disk brakes are established: models with 14-inch wheels have the disk brake mechanism with a floating bracket, models with 15-inch wheels have on forward wheels the disk brakes ventilated from within with a floating frame. Therefore when replacing brake shoes various working methods are used.

When cleaning brakes brake dust is removed. This dust is hazardous to health. Therefore when cleaning the brake system not to inhale dust.

Brake shoes are issued the plant only for certain models of cars. Therefore it is recommended to apply brake shoes AG VW resolved only.

Works in the brake system demand the most strict purity and accuracy. If there is no necessary experience, it is necessary to entrust work to experts.


At a paving, very wet from a rain, it is necessary to press a brake pedal during the movement from time to time to exempt disks from damp products of attrition. Though as a result of centrifugal forces moisture is thrown out from disks, however the thin silicone film, rubber attrition products, lubricant and pollution reducing reliability of brakes is formed in places.

After installation of new brake shoes they need to be ground in braking. To 200 km it is impossible without need to make sharp braking.

Corroded disk brakes when braking have effect of Rubbel which not to eliminate even with long braking. In this case disks are replaced.

The burned slightly dirt on brake shoes and flutes lead to formation of furrows on disks that reduces reliability of work of brakes.