2005 Mercedes Benz CLK 320 Technical Service Bulletin # S-60_00-008A Date: 001201

Special Tool - 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)
2000 Mercedes Benz CLK 320 (208.365) V6-3.2L (112.940) Page 210
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.


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.
2000 Mercedes Benz CLK 320 (208.365) V6-3.2L (112.940) Page 211
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.
2000 Mercedes Benz CLK 320 (208.365) V6-3.2L (112.940) Page 212
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
2000 Mercedes Benz CLK 320 (208.365) V6-3.2L (112.940) Page 213
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)