Drive Belt Tensioner - Modification/Installation

REF.No. 13/13a

To: OUR MERCEDES-BENZ PASSENGER CAR DEALERS

DATE: March 1988 (supersedes S.I. 13/13, Dec. 1987)

SUBJECT:
A. MODIFICATIONS TO POLY-V-BELT TENSIONER
B. INSTALLING MODIFIED POLY-V-BELT TENSIONER MODELS 201.024/028/034 WITH SINGLE BELT DRIVE

Note: The Parts Information Table has been revised.

A. Modifications To Poly-V-Be1t Tensioner








As of January 1987 (as of July 1986 for engine 102.985) a modified poly-V-belt tensioner is installed in these vehicles. This tensioner can be identified by the additional sheet metal bracket (47, Figure 1) the collar screw (25, Figure 1) and part no. 102 202 28 40 on the bracket's bushing (Figure 2). The procedure for installing the modified tensioner in vehicles prior to production phase-in is described in section "B" of this service information.





Effective Serial Number

Note:
Only the modified tensioner (which includes bracket and collar screw) is available when ordering replacement parts. The attachment screws must be ordered separately.





As of October 1986, a label with a modified adjust scale for tensioning the poly-V-belt is affixed to the tensioner (Figure 3).

B. Installing Modified Poly-v-Belt Tensioner





1. Loosen bolt (25) by approx. one turn, unscrew tensioning nut (24) from tensioning rod and remove poly-V-belt (27, Figure 4).

2. Remove lower engine encapsulation panel, remove screws (31), loosen screw (34) and swing shock absorber (28) downwards. Unscrew bolt (25) completely and remove belt tensioner (1, Figure 4).





3. Remove belt pulley from power steering pump. Unscrew nut behind the power steering pump/A/C compressor bracket from bolt (39). Remove screws (48 and 48a, Figure 5).

4. Install modified belt tensioner and sheet metal bracket (47). Grease thread and seat of collar screw M12 x 110 (25) and install. Seat screw and then back off 1/2 turn again. Screw tensioning nut on tensioning rod (Figure 5).

5. Attach bracket (47) with longer screws.

39 = M8 x 95
48 = M8 x 45
48a = M8 x 55

Tighten nut on bolt (39) and screws (48 and 48a, Figure 5).

Tightening torque: 21 Nm

6. Install belt pulley for passenger steering pump. Tighten attachment screw.

Tightening torque: 30 Nm

7. Attach bracket (29) with shock absorber (28) to belt tensioner. Tighten screws (31, Figure 5) and (34, Figure 4).

Tightening torque: 21 Nm

Install lower engine encapsulation panel.





8. Beginning with the tensioning pulley (1), install poly-V-belt in the order indicated. Check for proper seating of the belt on the pulley (Figure 6).

9. Move the adjustment pointer (22, Figure 7) to the left until the pointer is centered over scale line (A). Turn tensioning nut (24, Figure 4) to the right until the pointer is centered over scale line (E). Tighten collar (25, Figure 7).

Tightening torque: 80 Nm





Parts Information

Dealer stock of the previous version belt tensioner, 102 200 33 70 and 102 200 34 70, must not be used and must be returned to the facing PDC no later than January 29, 1988.

Time Allowance
13-0090 Belt tensioner, R & R - Check/Repl., if required 1.0 hrs. 41/44/47 (with Maint. or Repair work)

Damage Code
20 249 99 Belt tensioner, defective