Hydraulic Control Assembly - Antilock Brakes: Locations

Note: Complete brake master cylinders and brake boosters can be replaced separately.





1 Brake Booster
^ For gasoline engines vacuum is taken from the intake manifold
^ Diesel engines have a vacuum pump to create the required vacuum
^ Functional check:
- With engine switched off, depress brake pedal firmly several times (to exhaust vacuum in the unit)
- Hold brake pedal with average foot pressure in brake position and start engine. If brake booster is functioning properly, brake pedal should give noticeably underfoot.
^ If pedal does not give, replace brake booster
^ Check valve (in vacuum hose)
Functional check
^ Separating from brake pedal.
2 Cap
3 Brake fluid reservoir
4 Plug
^ Coat with brake fluid and press into reservoir
5 Retaining pin
^ Insert through brake master cylinder
6 Brake master cylinder
^ Cannot be repaired. If faulty, replace as complete unit
7 Hex nut, self locking 20 Nm (15 ft. lbs.)
8 Bolt, 8 Nm (70 inch lbs.)
9 Cap nut, 20 Nm (15 ft. lbs.)
10 ABS/EDL hydraulic unit
11 ABS control module
^ Control module connector is not disconnected before On Board Diagnostic (OBD)
12 Connection for brake line
^ Hydraulic unit to left front brake caliper
13 Connection for brake line
^ Hydraulic unit to right rear wheel cylinder/ brake caliper
14 Connection for brake line
^ Hydraulic unit to left rear wheel cylinder/ brake caliper
15 Connection for brake line
^ Hydraulic unit to right front brake caliper
16 Brake line
^ Brake master cylinder/pressure rod piston circuit to hydraulic unit
17 Brake line
^ Brake master cylinder/floating piston circuit to hydraulic unit
18 Hex nut, self locking, 20 Nm (15 ft. lbs.)
19 Hex nut, self locking, 20 Nm (15 ft. lbs.)
20 Seal
^ Always replace
21 Vacuum hose
^ Install in brake booster
22 Sealing plug
23 Hex nut, self locking, 20 Nm (15 ft. lbs.)
24 Seal
^ For brake booster
25 Boot
^ Ensure boot is properly seated or suction noises may be noticed
26 Bracket

Brake lines from brake master cylinder to hydraulic unit, connecting





Fig. 1 Vehicles with ABS
A Secondary piston circuit
B Primary piston circuit
1 Hydraulic unit to right front brake caliper
2 Hydraulic unit to left rear wheel cylinder/brake caliper
3 Hydraulic unit to right rear wheel cylinder/brake caliper
4 Hydraulic unit to left front brake caliper





Fig. 2 Vehicles with ABS/EDL
A Secondary piston circuit
B Primary piston circuit