Tools: Floor jack; Jackstands; Grease gun; Air pressure gauge
Aside from a flaming gas tank, there’s nothing more dangerous than worn suspension bushings or ball joints. Make sure the parts are sound and keep them greased.
The same regimen applies to tire pressure. Make a habit of checking tire inflation every time you put gas in the tank. Improper tire pressure will ruin the tires in short order. The following tips show you what to look for and how to fix it.
This is how you check for loose wheel bearings. To check for loose ball joints, place a jackstand or floor jack under the lower A-arms to unload the spring pressure. The best way is to put a long prybar under the tire and pull upward to see if the ball joint deflects. Expect a slight amount of movement, but if you can see the ball joint move, it has failed. The arrows indicate ball joint location. With this particular design, the bottom joint usually fails, but you should always replace both. | 
The load-bearing ball joint takes the most abuse. Usually it's the one in the control arm that locates the coil spring. In the Chevy shown in the top right, the lower arm carries the spring, but in this Ford example, the upper arm supports the load. To check this type of suspension for a bad ball joint, make sure the suspension is in full droop, then use a prybar on the tire, as described above. |
Grease all the suspension pivot points (anything with a zerk fitting) every six months or so. Pump the grease gun until grease begins to ooze out of the rubber boot, then wipe off the excess. | 
Sloppy steering is often a sign that tie-rod ends need replacing, but a worn steering box may also be the culprit. To check the tie-rod ends, twist them hard in both directions. They'll pivot naturally, but if they're loose, replace them. |
To drain a Hotchkiss-type rearend (like this GM 10-bolt), put a drain pan in place, remove all but the top bolt, and pry the cover away from the housing. If you're just doing a fluid change (and not swapping ring-and-pinion gears), check the fluid for tell-tale signs of metal. Scrape off the old gasket, put on the new one, and reinstall the cover. | 
Be sure to use the proper gear oil. A limited-slip differential, such as the one in the late-model Camaro axle shown here, requires an additive that's available at most parts stores or GM dealers. For details on other makes, see the owner's manual. |
Some axle covers have a filler plug, but most don't. The GM 10- and 12-bolt axles locate the fill hole on the passenger side of the housing, which can be difficult to reach. Attach a short piece of hose to the bottle (in this case the additive bottle) and insert it in the hole. The cavity is full when the lube dribbles out of the hole. Reinstall the plug. Happy motoring! |  |