Brake Fluid: Service and Repair
Special tool(s): 1158147 torque socket and 999 2809 brake piston puller
Replacement guidelines
We recommend replacing brake fluid every 48,000 km (30,000 miles), or every second year. In cars where the brake is used hard and often (e.g. in mountains or tropical areas of high humidity) fluid should be replaced each year.
Background
The reason brake fluid has to be changed is that it is hydroscopic. In other words, it absorbs water molecules from the air. This water is absorbed amongst other things via the brake hoses and brake fluid reservoir, which are made of rubber and plastic respectively, and are not totally impervious to water molecules.
Increasing the water level in the brake fluid means that the brake fluid's boiling point falls considerably and corrosion forms on the braking system components. This damages the braking system and makes it much less effective.
NOTE: Use genuine Volvo brake fluid marked DOT 4+. Never reuse brake fluid. Always keep brake fluid in original pack and well sealed.
Preparations [LL1]
- Obtain equipment (bleed unit) which can be used to pressurize braking system to 2-3 bar (34-43 psi).
- Obtain a collecting bottle and hose to collect brake fluid in.
Connecting bleed unit [LL2]
- Connect bleed unit to brake fluid reservoir. Follow manufacturers' instructions for connecting and using bleed unit.
Removing wheels [LL3]
- Jack car up and remove wheels all around.
Removing brake pads, rear [LL4]
- Remove brake pads from one of the rear brake calipers, as per KB2-KB3. Then continue as per instructions below. Service and Repair
Replacing brake fluid, rear [LL5]
- Remove protective cap from bleed nipple and connect collecting bottle hose. Open nipple about one full turn.
- Press brake caliper pistons back using tool 999 2809 (2 off), until pistons reach bottom of caliper. Leave tool on caliper.
- Pressurize braking system with bleed unit.
- Drain off 2-3 dl (0.6-0.8 pt) brake fluid.
- Close bleed nipple and remove hose.
- Install protective cap.
[LL6]
- Depressurize braking system using bleed unit. Remove tool from brake caliper.
[LL7]
- Install brake pads, rear.
- Install brake pads, as per KB7. Then continue as per instructions below. Service and Repair
- Depress brake pedal a few times.
- Repeat procedure as in steps LL4 - LL7, on the other rear brake caliper. Then go to LL8.
Replacement brake fluid, front [LL8]
- Remove protective cap from bleed nipple on one of the front brake calipers. Connect collecting bottle hose. Open nipple, about one turn.
[LL9]
- Push brake caliper piston to bottom of caliper using a bolt clamp. See illustration. Leave bolt clamp in pushed in position.
- Pressurize braking system with bleed unit. Drain off 2-3 dl (0.6-0.8 pt) brake fluid.
- Close bleed nipple and remove hose.
- Install protective cap.
[LL10]
- Depressurize braking system using bleed unit.
- Remove bolt clamp from brake caliper.
- Depress brake pedal a few times.
- Repeat procedure as per steps LL8-LL10, on the other front brake caliper. Then continue with LL11.
Removing bleed unit [LL11]
- Remove bleed unit connector from brake fluid reservoir.
Finishing [LL12]
- Depress brake pedal repeatedly until brake pistons are in normal position.
- Check brake fluid level and install reservoir cap.
- Clean off any brake fluid spillage with lukewarm water and car wash shampoo.
Installing wheels [LL13]
- Check that brake disc and rim contact surfaces are clean.
- Grease hub rim center guide with anti-rust agent 116 1038-3.
- Install wheel. Fit bolts hand tight, then tighten them across to 110 Nm (80 ft.lb). If using a nut runner, use torque socket 115 8147.
NOTE: The crosswise tightening and torque settings are important to prevent stresses arising in the brake disc.