Mercedes Benz C 43 AMG Technical Service Bulletin # S-58_30-103A Date: 001201

Mercedes Benz C 43 AMG Technical Service Bulletin # S-58_30-103A Date: 001201

Special Tool - Resistance Spot Welder

Date: December 2000

Order No.: S-SI-58.30/103A, 60.00/08A

Supersedes: S-SI-MBNA-58.30/103, 60.00/08

Group: 58, 60

SUBJECT:

ALL MODELS

MULTISPOT M83 RESISTANCE SPOT WELDER - (in addition to Multispot M80)

DaimlerChrysler AG and MBUSA, LLC have approved the use of the Multispot M83 Resistance Spot Welder (Figure 1) for automotive collision

repairs. Resistance Spot Welding is the preferred method of performing structure repairs according to Mercedes-Benz Repair Procedures to assure

the repaired vehicle will offer the same level of safety as the original design.

The Multispot M83 offers digital microprocessor control to monitor each weld, and it automatically corrects welding current and time as needed.

The M83 also offers many other innovative features:

1. Tools and cables are air cooled for extended duty cycle. The optional water cooled pliers and cables offer additional extended duty cycle.

2. Pneumatic welding pliers provide over 400 PSI (1800 N) of pressure at the tips.

3. High-speed central connection allows for fast changeover between tools.

4. Provides factory appearance welds.

5. An alarm to alert the technician if a weld cannot or should not be made.

6. Built-in diagnostic program to assist in diagnosing complaints.

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7. The Multispot M83 has a three phase power supply (this offers electricity savings), which results in a lower current load per phase and with it

the voltage drop. This means that full power (approx. 15%) is available even with a weak power supply.

8. Via welding with direct current, a better exploitation of the power provided by the unit is accomplished. Thus, the welding process is faster

due to continuous welding current.

9. Multispot advantage: All tools such as tongs with and without cable cooling (water) and electrode arms can be used with all Multispot units.

10. The operation and monitoring of all Multispot units are identical.

The microprocessor automatically adjusts machine settings for each tool used, for standard body panels. If working on thicker metals, input that

information into the machine. Maximum welds with the pneumatic welding pliers is 3 mm or 11 gauge (Figure 2). In areas where the pneumatic

pliers cannot reach, the single- sided welding gun may be used. This unit also comes with carbon rod and "mini-shrinking" tool for shrinking sheet

metal.

The Multispot M83 is supplied with the following standard equipment:

230 volt power supply unit

Spot welding tongs (includes 01/120)

Welding gun

Extractor tool

Wheeled cart with tool holders

Work box, including washers, T-pins, welding studs, and as well as other parts.

Optional electrode arms (Figure 3), allow the technician to reach most areas of the vehicle.

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Technical Data

Resistance Spot Welding

Resistance spot welding is the most frequently employed welding method in the production process. This method is based on the principle that a

resistor heats up when an electrical current flows through it. With spot welding tongs, the panels to be welded are pressed together by the electrodes

by means of a lever mechanism. The electrode tips have rounded shape to keep the electrical resistance low. A high current can now flow through the

circuit closed by the electrode tips. The high resistance heats the material until it becomes plastic and melts together. The pressure of the electrodes

prevents the material from flowing away.

Quality Assurance

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A sample panel should be spot-welded to check the quality of the weld spots and the settings of the welding tongs (pressure, amperage, welding

time). The welding sample can be clamped in a vise and the plates separated using pliers (unbuttoning test, Figure 5). If the weld spot on one plate

remains intact and a matching hole is produced in the other plate, then the weld is considered satisfactory (Figure 6).

In addition to quality testing by means of the unbuttoning method described above, particular attention must be paid to the condition of the

electrodes. The electrode surfaces must be checked for cleanliness and roundness before each use (reworking with an electrode cutter may be

required). Satisfactory welds cannot be produced with flattened or burnt-out electrodes.

Parts list

As the welding pliers and single-sided gun are used, the electrodes wear and flatten out. The electrode caps can be replaced or they can be reshaped,

using a drill and one of the two refacing tools. Beveled caps are reshaped likewise, using a file.

Note:

Both M80 and M83 units can be ordered with optional water cooled pliers which will increase duty cycle in high production workshops.

THE MULTISPOT M83 AND OPTIONAL ACCESSORIES CAN BE ORDERED VIA THE MBUSA STANDARD SERVICE EQUIPMENT

PROGRAM (SEE CATALOG OR PHONE [Toll Free] 1-888-458-4040)