148 Section 1 Introduction to Automotive Technology Copyright Goodheart-Willcox Co., Inc. Tech Tip When doing any kind of lubrication service, protect the customer’s vehicle from oil and grease damage. Use seat covers, paper floor mats, and fender cov- ers to protect surfaces from oil and grease stains. A stained carpet or seat cover can be very expensive to replace! Body Lubrication When performing a complete chassis lubrication job, you should also lubricate high-friction points on the body (hinges and latches on doors, hood, and trunk). This will help prevent squeaking doors, sticking hinges, and wear problems. Always use the prescribed lubricant. Normally, rubber and plastic parts will deteriorate if exposed to petroleum-based lubricants (oils and grease). Silicone lubricant should be used on plastic and rubber com- ponents. See Figure 9-18. The most common types of body lubricants are: • Engine oil—Engine oil is used on hard-to-reach high-friction points. • Graphite—Graphite is excellent for door and trunk locks. It will not collect dust and dirt, which could upset lock operation. • Dry stick (wax) lubricant—Dry stick lubricant is desirable on door latches and strikers (post that engages door latch). It will not stain clothing. • Chassis grease—Chassis grease is good all- around body lubricant. It can be used on easy-to- reach hinges and latches. • Silicone lubricant—Silicone lubricant often comes in a spray can. It is especially suited for rubber door weather stripping and windows. It is a dry lubricant that will not soil windows and clothing. Checking Tires Service Procedure To check a vehicle’s tires for safety: 1 Inspect the condition of the tire treads. Gener- ally, all grooves in the tire should be at least 1/8″ (3.2 mm) deep. If they are worn more than this, inform the shop foreman or vehicle owner. New tires are recommended to im- prove traction and prevent a dangerous tire failure or “tire blow out.” 2. If tire tread wear is minimal, measure tire inflation pressure. 3. Remove the valve stem cap and press the tire gauge squarely over the valve stem. 4. Read and compare the air pressure indicated on the gauge with the vehicle manufacturer’s inflation specifications, which are listed on C—Place a dab of grease on door hinges. D—Lubricate the hood latch to prevent it from rusting. A—Lubricate hood and trunk hinges. B—Use non-stain wax on door strikers. Volvo Figure 9-18. During lubrication service, lubricate body com- ponents to prevent squeaks and wear.