Disassembly of the brake caliper body is carried out when replacing pistons, pins, sealing rubber parts

To disassemble the body you need:

- disconnect the flexible hose from the brake caliper body;

- remove the brake pads;

- remove the brake pads and mark them so that they can be put back in their original place during subsequent assembly;

- remove the finger cover from the base;

- remove the body with a finger from the hole in the base;

GAZ-2705 front brake repair

- install a wooden block 20-25 mm thick between the piston and the body (Fig. 1);

- push the piston out of the cylinder by connecting a hose with low air pressure to the body inlet;

- remove the piston cover from the piston groove and remove the piston from the body, and the cover from the body groove;

- remove the sealing ring from the housing with a blunt spatula.

After completing these steps, wash all parts with isopropyl alcohol or fresh brake fluid. Do not use gasoline, thinners or other mineral-based fluids for flushing

Check all parts for wear, damage and corrosion, paying particular attention to the piston surfaces and cylinder bore.

The edges of the sealing ring must be sharp, without rounding, and the surfaces should be smooth, without tearing.

If there is severe corrosion on the working surface of the piston, it must be replaced.

Assembling the caliper housing

After checking and replacing failed parts, assemble the brake caliper housing, taking into account the following recommendations:

- before assembly, make sure that the working and sealing surfaces of the body are clean; lubricate the sealing ring with NG-213 liquid TU 38.10.1129-80 and install it in the housing groove;

GAZ-2705 front brake repair

- lubricate the working surface of the piston and the boot with NG-213 liquid and install the latter on the piston (Fig. 2).

Without moving the cover from the end of the piston, fill it into the groove of the body;

- carefully insert the piston with the cover into the opening of the housing by hand. Fill the boot into the piston groove;

- install the body with fingers into the holes of the base;

- put the pads in their original place;

- connect the flexible hose to the body of the bracket.

Replacing the guide pins must be done in the following order:

- perform operations to remove the brake pads. In this case, the pads should be marked so that they can be installed in their original place during subsequent assembly;

GAZ-2705 front brake repair

- unscrew the bolt securing the second guide pin (Fig. 3);

- remove the finger covers from the base;

- remove the guide pins from the base holes;

- replace worn guide pins, after lubricating them with UNITOL-1 grease and putting protective covers on them (covers should not be damaged);

- perform the previous operations in reverse order.

Replacing the base

To replace the base you need:

- detach the body from the base (see above);

- remove the brake pads from the base and mark them so that they can be put in their original place during subsequent assembly;

- unscrew the two bolts securing the base to the steering knuckle and remove the base;

- install a new base on the knuckle and tighten the bolts of the base with a torque of 100-125 Nm (10-12.5 kgf m), having previously cleaned the threaded surfaces of the knuckle and bolts from the old sealant and apply fresh Unigerm- 6" TU 6-01-1285-84.

Further assembly (see "How to replace the Gazelle front wheel brake caliper") .

Brake disc repair

The disc is repaired if its working surfaces have deep scratches and axial runout of more than 0.1 mm.

The axial runout of the working surfaces of the disc is checked by an indicator when the disc rotates on the hub bearings. To repair the disk you need:

- remove the body and base from the steering knuckle;

- remove the disc from the hub, for which unscrew the bolts with spring washers;

- grind the working surfaces of the disk on the basis of its end surface adjacent to the hub.

When grinding, it is necessary to ensure a minimum difference in processing between the walls of the disk.

The value of the total tolerance of parallelism and flatness of the working its surface of the disk relative to the base surface should be no more than 0.05 mm (which corresponds to the difference in the indication of the indicator when it is moved along the surface being checked), and the value of the total tolerance of the parallelism of the working surfaces of the disk to each other should be at least 0.03 mm.

The thickness of the disc after grinding should be at least 19 mm, and the roughness of its working surfaces should be no more than 1.25 microns in accordance with GOST 2789-73.

If cracks or deep scratches are found, as well as if the disc thickness is less than 19 mm, it is necessary to replace the disc with a new one.

To do this, install the disc on the hub and tighten the disc fastening bolts with a torque of 44-56 Nm (4.4-5.6 kgf m). Install the brake caliper housing on the steering knuckle (see "How to replace the front wheel brake caliper of a Gazelle car» ).