HCU (Hydraulic Control Unit): Assembly

Fig 1: MK25E Solenoid Valve Seal

Courtesy of DAIMLERCHRYSLER CORP.

1 - SEAL

2 - SOLENOID VALVE STEM

1. Clean any debris off the mating surfaces of the HCU and ABM module.
   CAUTION: When installing new O-rings or solenoid valve stem seals, do not use any type of lubricant.
2. If the seals on the components are not new, they must be replaced. Each of the solenoid valve stem seals (1) must be replaced. See Fig 1; do not reuse solenoid valve stem seals  .
   Fig 2: MK25E Internal Pump Connector O-Ring

   Courtesy of DAIMLERCHRYSLER CORP.

   1 - O-RING

   2 - O-RING MOUNTING GROOVE

3. The pump/motor connector O-ring (1) should also be replaced if not new. See Fig 2
   Fig 3: ABM Assembly To HCU

   Courtesy of DAIMLERCHRYSLER CORP.

   1 - ABM

   2 - HCU

   3 - SOLENOID VALVE STEM

4. Align components and install the ABM module on the HCU. See Fig 3.
   Fig 4: MK25E ABM Mounting Screws

   Courtesy of DAIMLERCHRYSLER CORP.

   1 - MOUNTING SCREWS

   2 - ABM

5. Install the four screws attaching the ABM module to the HCU. See Fig 4. Tighten the mounting screws to 2 N.m (17 in. lbs.) torque.
6. If the mounting bracket needs to be installed, install the mounting pins in the HCU as necessary and tighten to 11 N.m (97 in. lbs.) torque. Insert the mounting pins into the grommets mounted in the bracket, then install the single mounting bolt. Tighten the mounting bolt to 11 N.m (97 in. lbs.) torque.
7. Install the HCU in the vehicle (refer to INSTALLATION ).