GM Astro/Safari 1985-1996 Repair Guide



For a number of different reasons, exhaust system work can be the most dangerous type of work you can do on your van. Always observe the following precautions:

Support the van extra securely. Not only will you often be working directly under it, but you'll frequently be using a lot of force, such as heavy hammer blows to dislodge rusted parts. This can cause an improperly supported van to shift and possibly fall.
Wear goggles. Exhaust system parts are always rusty. Metal chips can be dislodged, even when you're only turning rusted bolts. Attempting to pry pipes apart with a chisel makes chips fly even more frequently. Gloves are also recommended to protect against rusty chips and sharp, jagged edges.
If you're using a cutting torch, keep it at a great distance from either the fuel tank or lines. Stop frequently and check the temperature of fuel and brake lines or the tank. Even slight heat can expand or vaporize the fuel, resulting in accumulated vapor or a liquid leak near your torch.
Watch where your hammer blows fall. You could easily tap a brake or fuel line when you hit an exhaust system part with a glancing blow. Inspect all lines and hoses in the work area before driving the van.

Be very careful when working on or near the catalytic converter. External temperatures can reach 1500°F (815°C) and more, causing severe burns. Removal or installation should be performed only on a cold exhaust system.

A number of special exhaust system tools can be rented from auto supply houses or local stores that rent special equipment. A common one is a tail pipe expander, designed to enable you to join pipes of identical diameter.

It may also be quite helpful to use solvents designed to loosen rusted bolts or flanges. Soaking rusted hardware the night before you do the job can speed the work of freeing rusted parts considerably. Remember that some solvents are flammable. Apply them only after the parts are cool.

Two types of pipe connections are used on the exhaust system, they are: the ball joint (to allow angular movement for alignment purposes) and the slip joint. No gaskets are used in the entire system.

The system is supported by free hanging rubber mountings which permit some movement of the exhaust system but do not allow the transfer of noise and vibration into the passenger compartment. Any noise vibrations or rattles in the exhaust system are usually caused by misalignment of the parts.

Before performing any operation on the exhaust system, be sure to allow it to cool down.