FRONT FRAME X-MEMBER CRACK (WELD CRACK & WELD ON PLATE)

SUBJECT: FRONT FRAME CROSSMEMBER CRACK (WELD CRACK AND WELD ON PLATE (Revised to correct typographical error)

VEHICLES AFFECTED: 1988-90 Cl, C2, TRUCKS

Some 1988, 89 or 1990 Cl, C2 and C3 light trucks subjected to extreme frame flexing in severe duty may experience front frame crossmember cracking. The crack may start at the bottom corner of the right lower control arm pocket and extend up the side, refer to Figure 1.

Trucks experiencing this condition should be repaired by drilling a stop hole at the end of the crack, welding the crack and welding a plate over the crack using the following procedures:

IMPORTANT: Use filler metals from a freshly open container.

GMAW - Gas Metal Arc Welding use: Electrode E708-4

SMAW - Shielded Metal Arc Welding use: Electrode E7018

NOTICE: Disconnect battery (batteries) when arc welding on vehicle to avoid electronic component damage.

SERVICE PROCEDURE:

1. Disconnect battery (batteries).

2. Remove right side lower control arm. (Refer to Service Manual section 3-C).

3. Clean or grind crossmember surface to determine end of crack.

4. Drill 3mm (1/8") stop hole at each crack end.

5. Fill entire length of crack with weld and grind smooth.

6 Cut a piece of 3mm (1/8") or 5mm (3/16") thick 1008 of 1010 steel using the shape in Figure 2 as a template.

(a) Disconnect and connect brake line retainer at frame, move brake line aside.

7. Clean crossmember to prepare for welding plate to crossmember.

8. Using c-clamp or vise gripe, clamp plate to bottom of crossmember so the arch in the plate circles the hole in the cross- member with the rear of the plate to the rear of the vehicle.

9. Weld plate to crossmember in the arch and the straight edge opposite the arch with 25mm (1") welds 19mm (3/4") apart.

10. Using a torch, heat the front and rear portions of the plate and work them to conform to shape of crossmember.

11. Weld front and rear of plate to crossmember continuing with 25mm (1") welds 19mm (3/4") apart.

NOTE: It may be necessary to clamp front and rear of plate to crossmember to ensure tight fit when welding.

12. Spray paint plate black.

13. Reinstall lower control arm.

14. Reconnect battery (batteries).

For vehicles repaired under warranty, use:

Labour Operation: T8065

Labour Time 1.5 Hours.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.