Dismantling and overhauling the wheel brake cylinder (VW Transporter T3)

Attention! When repairing, install parts from the repair kit as a set.

The circle in the figure indicates the parts included in the repair kit.



Unscrew the brake line from the cylinder and close the air bleed plugs with a protective cap.

Caution! No dirt must enter the pipeline.

Loosen the cylinder mounting bolt and remove the cylinder.

Disassembly

The wheel brake cylinder can be overhauled even when it is installed. Overhaul is necessary if the seals are loose or if the piston is stuck. The cylinder must be replaced if it has scratches or rust. Removing them is not allowed. It is better to replace a defective cylinder as a set; overhauling the cylinder is recommended only in very rare cases. When overhauling, use a complete repair kit, paying attention to the diameters of the parts, since there are cylinders of different designs.



Remove the protective cover. Pull out the piston with the cuff and pressure spring.

Clean all parts with brake fluid or alcohol. The cylinder can be cleaned with a lint-free cloth. A clean piston should move back and forth in the cylinder with a "sucking" motion.

Slide new seals onto the piston, with the long flange facing the cylinder. Lubricate the seals, piston and cylinder with a special paste for brake cylinders.

Replace the air bleed plug if necessary.

Replace damaged or rusty pipelines.

If the surface is damaged, clean it with a calcium-based neutralizer and dry it. Then apply a thin layer of anti-corrosion primer ALN 747003.

After cleaning the pipelines, they must be protected with AKR 321 M 15.4 ointment.

Remove the pipelines and, if possible, lay them in their old places.

When connecting pipelines, moisten the conical adjacent surfaces with a few drops of brake fluid and tighten with a torque of 15-20 Nm.

Finally, bleed the brake system of air.

Caution! The brake lines are coated with a layer of plastic to protect against corrosion. If this layer is damaged, this may lead to corrosion of the lines. Therefore, the brake lines must not be cleaned with wire brushes, sandpaper or a screwdriver.