Hydraulic pipes and hoses — inspection, removal and installation (Nissan Bluebird T12)

1. The brake hydraulic system contains many metal hydraulic pipes that run from the master cylinder (on early models, via a connector block and a pressure reducing valve) through the engine compartment bulkhead and along the inner fender panels to the front brakes, or along the underbody to the rear brakes. Flexible hoses run from the suspension inside the arc of each wheel directly to the brake (photo). Figures 9.1 and 9.2 show the schematic arrangement of the brake system components.





2. When checking the system, first look for signs of leaks at the tube or hose couplings, then check the condition of the flexible hoses. Check that the pipes and hoses are securely fastened in brackets or hangers (photo).





3. Carefully move along the metal hydraulic pipes, looking for dents or damage of any kind or corrosion. If the depth of corrosion is significant, the pipe must be replaced.

4. If the tube or hose is to be replaced, remove the master cylinder reservoir cap and cover it with a piece of polyethylene to seal the system. If the flexible hose is to be disconnected, unscrew the hose coupling nut before removing the spring clip securing the hose to the mounting bracket.

5. To loosen the coupling nuts, it is preferable to have a special wrench of the appropriate size. Always clean the coupling and the surrounding area before disconnecting. When removing a component with more than one coupling (for example, the connector block on early models), note the connection points of all the tubes.

If a hydraulic tube needs to be replaced, cut off the piece to be replaced and have the dealer mold a new tube. Alternatively, hydraulic grommets can be purchased from most parts stores, but this requires very careful measurement of the original. The most reliable way is to take an old tube as a sample.



7. When installing, do not overtighten the union nuts. The tightening torques specified in the specification are not high. When installing flexible hoses, always replace the sealing gaskets on each side of the bungee joint (where are there) and tighten the banjo bolts to the specified tightening torque Specification.

8. Check that the pipes and hoses are correctly routed and secured in the brackets or hangers (photo). After installation, remove the polyethylene from the reservoir and bleed the hydraulic system as described in Chapter 8 from this Section.