How To Maintain Your Auto Chassis
Car chassis are an under-maintained but vital part of every automobile and knowing how to properly care for yours can add years to the life of your vehicle. That’s because the chassis is constantly in motion, between the way it channels the engine’s power into propulsion and the way it takes the physical feedback that makes it through the suspension system as you drive. Lubricating your chassis every six months is the best way to keep it functioning and to ensure it is working with other vital structural components to deliver the smoothest ride possible.
Know the Chassis Lubrication Points
Chassis lubrication covers not only the proper care of the car’s U-joints or CV joints, but also related components, including much of your car’s suspension.
- Sway bars
- Steering joints, including ball joints
- Suspension joints
New DIYers need to remember that terms like bushings refer to multiple points on most vehicles, because there are a variety of types of bushings and many cars use more than one in their suspension systems.
How to Lubricate Chassis Parts
Once you have identified all the locations you will need to lubricate, you need to make them accessible. Since the chassis parts are mostly accessible from the underside of the car, that means it will need to be put up on jack stands or hoisted in a lift. If you are working without a full lift, remember to use secure jack stands and braces, not just a hydraulic jack. The weight distribution and secure placement you get with proper stands is a vital safety measure.
Next up, you’ll need to load your grease gun. Here’s how that works if you’ve never used one before:
How to Load a Grease Gun
Lock Your Grease Gun
Pull back the plunger on the grease gun and lock it into place. You should feel a click when it locks. If you aren't sure that it has locked, lower your draw pressure without letting go and see if it tries to retract. If it does, keep pulling. Some grease guns take a little muscle to lock open.
Open the Barrel
Unscrew the main barrel that holds the grease. If you started with a loaded gun and you are reloading, remember to clear out the old grease tube.
Open the Cartridge
The new cartridge has a pull tab on one end to open it. That tab goes on the pump head side. The other side has a plastic cap, that goes on the plunger side.
Load the Grease Tube
Remove the plastic cap and pull tab, then seat the grease tube in the barrel. If your old tube had any extra left, pack it in to the new one
Put it Back Together
Screw the barrel together, then attach the zerk by putting the connector on and clicking it into place. The zerk is a hose that connects to the auto's grease reservoir when lubricating vehicles.
Now you’re ready to climb under the vehicle and lubricate the points you already identified. Of course, they can look a lot different once you are under the vehicle than they did when you were planning things out. Make sure you have an automotive maintenance manual on hand for the model and year you are servicing while you work. Taking your time and using proper area lighting, work through each diagram until you have found and filled each reservoir at the lubrication points. When operating the grease gun, connect the zerk to the reservoir’s fill point and squeeze the trigger until you see a little excess grease come out. It doesn’t hurt anything to slightly overfill it, so it’s better than accidentally underfilling.
Not all of you lubrication points will have grease fittings. Many suspension joints and bushings need to be lubricated directly. For polyurethane components, a sprayable mixture of silicone and alcohol available widely will do the trick. For metal joints and bushings, you will need to disassemble the component, apply grease directly to the contact surfaces, and then reinstall it. With the proper tools this should not add too much time, because they only need to be removed far enough to access the surfaces in need of lubrication.
Inspecting the Underside of Your Vehicle
Before calling the project complete and lowering the car, it’s good practice to inspect the components you just serviced and make sure nothing needs replacement. For the suspension parts with no grease reservoir, you can look for signs of wear or breakage as you go. For the U-joints and other components serviced without disassembly, you need to make an extra effort.
Remember, U-joints on rear-wheel drive vehicles require spinning, so the vehicle needs to be in neutral when you are accessing the grease reservoirs. While you are spinning the joints, take the time to see if it has any play sliding fore and aft. If it does, that’s a pretty good sign the u-joints need replacing.
For the CV joints on the front end, check the boots for cracking, and schedule a replacement if needed. Taking the time to lubricate your chassis means taking the opportunity to look at the suspension parts that take most of the hits when you are on a rough patch of road, so you can get them replaced before mechanical failure sidelines you on the highway.
All told, this project should take an hour end-to-end for most DIYers. Experienced mechanics, whether professional or home hobbyists, can probably get it down to 30 minutes with the right tools and a good process, but if you are new to the task, it’s more important to slow down and make sure you service every component. Repeating this task on time lengthens the life of your vehicle, but it also reduces the extra noises you hear while driving by silencing the contact points in the leaf spring bushings, ball joints, and other moving parts of the chassis. As part of a balanced maintenance routine, it can also lengthen the life of your brakes and tires by ensuring the drivetrain and suspension are both working smoothly, so make sure you have car chassis lubrication supplies on your order the next time you stock up on automotive supplies your local AutoZone.