You need to spend a little quality time with your truck every now and then. Up close and personal, if you know what I mean. On your back, down and dirty with the zerks between your fingers.

Greasing your truck yourself has obvious benefits of course, one of which is the opportunity to have a good look around to make sure everything is as it should be. Let’s face it, the lad who works in the grease pit may be really good at his job, but he doesn’t know your machine as well as you. It can’t hurt to give ‘er the old once-over while you’ve got the grease gun in your hand.

The lubricant used in a chassis grease serves three key functions: it minimizes friction between moving metallic surfaces; it protects exposed surfaces from rust and dirt contamination; and applying grease to a fitting helps to purge existing contaminants.
But first you’ve got to get the grease to where it’s needed.

There are dozens of grease fittings on a truck, which all need their share of attention – some more than others. Identify all the locations before you start, and stick to the same pattern each time so nothing will be forgotten. Before applying new grease, the tip of the zerk fitting should be wiped clean of dirt and old, dry grease. And because grease is messy and sticky, carefully align the grease gun fitting to the zerk fitting to avoid any spillage. Gobs of excess grease only attract dirt and will eventually wind up stuck to somebody’s windshield.

Before greasing the front end, it’s advisable to jack up the truck using the I-beam for support. This takes the weight off the kingpins and ball joints. Critical locations such as these, exposed to water and spray, should be greased on a weekly basis. Apply grease until it begins to seep out of the tie-rod cups and the flanges around the kingpins.

Greasing the clutch release bearing and the transmission cross-shafts requires a little care. Grease around these parts isn’t likely to be washed away by water spray, so they needn’t be greased more than once a month. Camile Thebeau, shop foreman at Brentwood International in Moncton, N.B, cautions not to apply too much grease to these fittings.

“A single pump stroke is sufficient for the release bearing and the cross-shafts,” he says. “Any more than that and you risk contaminating the surface of the clutch, or the clutch brake, with the excess grease.”

U-joints, he says, should be greased frequently. It doesn’t matter which of the two fittings you use, just make sure that you pop grease from all four of the cups on each one. If grease won’t emerge from one or more cups, you should have the U-joint inspected.

The brake cam bushings also require a sparing application of chassis lube. Too much there and you risk the contamination of the brake linings and drums. Slack adjusters, like the U-joints and tie-rods, are exposed to water and dirt, so grease them liberally and wipe away any excess.

And don’t forget the fifth wheel. Grease the plate regularly, but sparingly. Any excess will simply squish out and mess up the undercarriage. Grease the locking mechanism and the support bushings as well.

The trick to chassis lubes is to use a high-quality lubricant in sufficient quantity to do the job with out having it ooze out and spread itself all over the truck.

There are specific greases designed for service in heavy truck applications, so watch what you buy. Not any old grease will do. Failure to observe proper lubrication requirements may cause premature failure of certain components. That, or use of the wrong grease formulation, may well void your warranty.

Use a grease that’s recommended, or at least approved, by the vehicle manufacturer and one that meets the highest performance standards set by the National Lubricating Grease Institute (NLGI). Use a GC-grade for wheel-bearing applications and LB-grade for chassis applications. In summer service, an NLGI grade 2 is ideal for grease-gun application. A lighter, number 1 grade may be more suitable in winter. Automatic greasing systems generally call for a grade 00, 0, or 1, depending on the system.

If you switch greases from time to time, ensure the products are compatible with other products and seal materials. Incompatible lubricants may harden or become runny when mixed. They’re not much good to you if they just run out of the fitting. Nor is a grease that’s too hard to flow into the fitting and do its job.

A grease job isn’t rocket science, but a grease job done properly can cut a pile of surprise costs from your bottom line. You can trust your investment to the lad down at the local service center, but make sure he knows what he’s doing. Or you can do it yourself, and combine the exercise with the all important weekly and monthly vehicle inspection. Either way, you’re going to get your hands dirty, but think of the money you’ll save.