Paint mark the position of the front wheels in relation to the hubs. This is necessary to reinstall the wheels in their original position, as a result of which their balance is maintained. With the vehicle on wheels, loosen the front wheel bolts. Raise the front of the car and secure it on stands, unscrew the bolts and remove the front wheels.
Attention. Be sure to replace all the pads on one axle of the car, even if only one pad has reached the wear limit. If the brake pads are to be reinstalled, they must be marked before removal.
Using a screwdriver blade on the outside of the caliper, remove the retaining spring (see fig. 11.3).
Remove the top and bottom dust caps covering the guide pin heads (see fig. 11.4).
Unscrew both guide pins from the caliper (see fig. 11.5).
Raise the caliper with the inner shoe and soft wire, tie it to the A-pillar, while the caliper should not hang on the brake hose, and should not be stretched or twisted.
Remove the outer brake pad from the caliper holder.
Remove the inner brake pad from the caliper piston.
Installation
Attention. Do not press the brake pedal with the brake pads removed, otherwise the piston will be squeezed out of the caliper.
Use a rag and alcohol to clean dust and dirt from the bearing surface and the place where the pads are installed in the caliper. Do not use solvents containing mineral oils or sharp tools.
If the pads are serviceable, clean them using a wire brush and a rag.
When installing new brake pads, remove the protective film from the surfaces of the outer brake pads.
Check the brake disc for cracks, especially around the wheel bolt holes, and for wear or mechanical damage, and regrind if necessary, provided that the thickness of the disc after machining is within limits.
Measure the brake disc thickness.
Check the caliper piston dust cover for cracks. Otherwise, immediately replace the cover, as the dirt that has penetrated into the cylinder violates the tightness of the caliper. To perform this work, you must disassemble the caliper.
Attention. If the brake pads are very worn, check the smoothness of the piston in the caliper cylinder. To do this, insert a wooden block into the caliper and ask the assistant to slowly depress the brake pedal. The piston should easily exit the caliper cylinder and also easily enter it. Make sure the piston is not completely out of the cylinder. With a heavy piston stroke, it is necessary to repair the caliper.
When installing new brake pads, with a special tool, press the piston into the caliper (see fig. 11.6). To press the piston into the caliper, you can use a wooden rod or a hammer handle. When doing this, make sure that the piston is not warped, and that the surfaces of the piston and dust cover are not damaged.
Attention. When the piston is pushed in, the brake fluid is forced out of the brake cylinder into the reservoir, so constantly monitor the fluid level in the reservoir, and if necessary, pump out a small amount of fluid from the reservoir.
Safety instructions
When draining brake fluid, use a deaeration bottle or plastic bottle that is designed for use with brake fluid only. Brake fluid is poisonous, so it must not be sucked out by mouth through a hose. Use a bellows for this. After replacing the brake pads, the brake fluid level in the reservoir must not exceed the mark «MAX», as the volume of the brake fluid increases with heating. Leaking excess brake fluid gets on the brake master cylinder, destroys the paintwork and contributes to the formation of corrosion.
Install the inner pad on the caliper, while the spring clip should be installed in the piston recess (see fig. 11.7). There is an arrow on the inner brake shoe with a spring, which must coincide with the direction of rotation of the brake disc when the vehicle is moving. If the brake pad is installed incorrectly, extraneous noise may occur during braking.
Remove the protective film from the outer brake pad.
Install the outer brake pad onto the caliper holder, being careful not to damage the adhesive layer on the back of the pad.
Install the inner pad caliper onto the caliper holder. Screw in the caliper guide pins and tighten them to 25 Nm.
Install both dust caps over the caliper guide pins.
Install the retaining spring on the caliper.
Attention. Once installed, the spring should compress under the caliper holder. If the spring is incorrectly installed, the outer brake pad will not automatically adjust the pad clearance due to pad wear, so pedal travel may increase.
Apply a thin layer of lubricant to the shoulder that centered the wheel disc. Install the wheel, aligning the previously applied marks, and secure it with bolts. Lower the vehicle to the ground and tighten the wheel bolts to 120 Nm.
Attention. Depress the brake pedal several times until the brake pads press against the brake disc.
Check the brake fluid level in the reservoir and top up if necessary.
Being careful, let the new brake pads run in to the brake disc. To do this, brake the car several times from a speed of 80 km/h to a speed of 40 km/h. Allow the brakes to cool down between braking.
After installing new brake pads, avoid hard braking during the first 200 km of the vehicle.
Pic. 11.8. Front brake caliper with two HP-2 pistons
1 - brake disc,
2 - caliper holder,
3 - holder (line)
4 - washer,
5 - bolt with ribbed head base, 190 Nm,
Before screwing in, clean the ribbed base of the bolt head.
6 - fixing spring,
It is not removed, but only moved to the side.
7 - latch,
8 - electrical connector,
9 - brake hose,
10 - bolt, 25 Nm,
11 - bracket,
12 - brake pipeline,
13 - brake pads
The left and right brake pads have different designs.
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