ABS - Hydraulic Unit/Relays Modified

TO: OUR MERCEDES-BENZ PASSENGER CAR DEALERS

DATE: August 1986 REF.NO.. 42/97


SUBJECT: MODIFIED ABS HYDRAULIC UNIT ALL MODELS

FIGURE 1 - ABS HYDRAULIC UNIT:

As of August 1985, a modified ABS Hydraulic Unit has been phased into production. It is recognizable by a bevelled cover showing the letters ABS (A, Figure 1). At the same time the valve and motor relays have been modified (see repair instructions).
Repair Instructions

1. The test procedure for the ABS system remains unchanged.

2. The modified ABS hydraulic unit can be installed instead of the earlier version, when using the appropriate relays and mounting clamps.

3. The plastic cover of the modified ABS hydraulic unit is fastened with a Torx-head screw. A T-5 driver is needed.

FIGURE 2 - VALVE RELAY:

4. The modified valve relay now contains a diode, which was previously a part of the hydraulic unit relay socket. As a result, the relay has six pins versus the previous version's five pins. (A, Figure 2).

FIGURE 3 - MOTOR RELAY:

In case of a defective diode, now only the valve relay needs to be replaced.

5. Due to the dimensional changes of the hydraulic unit cover, only the new motor relay fits in the modified hydraulic unit (A, Figure 3).
Parts Information


Part Name

Part Number

Modified version Previous version


ABS Hydraulic unit 001 431 80 12 001 431 68 12
Valve relay 001 542 67 19 05 001 542 02 19
Motor relay* 001 542 65 19 001 542 49 19
Mounting clamp 000 546 13 75


*included with hydraulic unit

Time Allowance according to latest Time Guide Microfiche