Most shops have lifts which pick the entire car up over their heads, allowing them to walk under the car and work on it quite easily. The oil change "Quick Lube" places have a pit which you drive over: the oil change people "hang out" in the pit.
If you are fixing your own car you probably don't have access to any of these things. Many do-it-yourself mechanics are KILLED every year, CRUSHED TO DEATH by cars that are not properly supported. It is, however, possible to lift and support a car safely without buying a $5000 lift or digging a pit to drive over.
PICKING YOUR CAR UP SAFELY
First, choose your surface. A flat smooth concrete surface is ideal. Asphalt is a small problem: jacks and jack stands will "sink in" to asphalt, especially in hot weather. Dirt is the worst surface to work on.
If you have no choice but to work on an asphalt (or even dirt) surface, a sturdy piece of plywood (at least 3/4 inch) under the jack stands can prevent the jack stands from sinking into the asphalt or even dirt. Another piece of plywood under the jack will keep it from "digging in" to the asphalt, or sinking into the dirt.
Bear in mind that the car moves in relation to the ground as you lift it. If you have a rollaround jack it will roll to compensate for this. If you are on asphalt or dirt, or if you have a jack that does not roll, you might want to leave the car in neutral with the park brake off to allow the car to roll to compensate for this. CAUTION: ONLY ATTEMPT THIS ON A PERFECTLY LEVEL SURFACE!!!
The ONLY way to safely support a car is using good jack stands! NO JACK IS SAFE BY ITSELF!!! After you have placed the jack stands under a "storng place" under the car, slowly lower the jack until it is resting completely on the jack stands. I will often raise the jack back up to where it is barely touching the place I jacked it up by, just for a "backup" for the jack stands. Of course sometimes this isn't possible: the jack would be in the way.
BEFORE YOU CRAWL UNDER THE CAR go up to it and push on it from side to side. It should be "solid" on the jack stands. If it moves AT ALL you need to support it differently.
COMMON TYPES OF JACKS
These things aren't even that safe for changing a tire, much less getting under a vehicle to work on it. Bumper jacks have killed more people than any other "support" device. They fail many ways: the car can roll forward or backwards off the jack, the jack can "pop off" the bumper unexpectedly, and the rachet mechanism itself can fail.
These are a bit better than a bumper jack because they go under the suspension rather than on the bumper, and thus have a lower center of gravity. They still aren't safe enough to support a car to work on, though.
HYDRAULIC BOTTLE JACK
Bottle jacks are a bit safer than scissor jacks, but still not safe enough to work under.
HYDRAULIC ROLL AROUND JACK
These are the "Floor Jacks" used in professional mechanic shops. Their wheels allow them to roll forward and backward to keep them in the same place where they touch the car: as the car goes up, the point where the jack touches the car moves a bit. These jacks can still tip over sideways, though, and can fail hydraulically and mechanically.
IN SHORT, IT IS NOT SAFE TO GO UNDER A CAR SUPPORTED BY JUST A JACK, NO MATTER HOW GOOD THE JACK IS!
Remember:the ONLY safe way to support a car that you are going to go under is with jack stands. A jack stand has a wide base with an adjustable pedistal which supports the car. A car properly supported by jack stands can be worked on safely.
JACK STAND SUBSTITUTES
There really is no substitute for getting a set of jack stands. You can get a good set at a parts house for less than $50. You can get much cheaper ones, but look for a wide base so they won't tip over: do you really want to save a few bucks and lose your life?
Nevertheless sometimes you may need to support a car when you don't have jack stands. People use a lot of methods to do this. NONE OF THEM ARE AS SAFE AS JACK STANDS!!!
UP ON BLOCKS
This can be EXTREMELY DANGEROUS!! DON'T DO IT!! BLOCKS CAN SUDDENLY CRUMBLE AND DROP THE CAR ON YOU!!
That being said, you can (at your own risk) put a car up on blocks if you don't rest the car directly on the concrete block. First: make sure to orient the block with the holes vertical. This is the way the block is designed to be installed in a wall. Put a strong piece of wood on top of the block to prevent the metal edges on the car from touching (and potentially crumbling) the concrete block. The piece of wood should be long enough to go all the way across the long dimension of the block. NEVER put a car on a concrete block just by itself.
CROSSTIE SECTION AND BIG WOOD BLOCKS
These won't crumble, and if they are big and tall enough the are OK if you put them under the suspension somewhere. DON'T STACK UP BLOCKS!!! THEY CAN TIP OVER AND DROP THE VEHICLE!!!
Pull It Yourself junkyards have their cars up on old rims. Because they have a wide surface area and are strong, they may be safer that jack stands! Of course they aren't adjustable.
DRIVE-ON CAR RAMPS
Once a car is on these they can be semi-safe, although driving on or off them can be hazardous. The danger is that a car can roll off these quite easily. It's also quite hard to drive on these ramps and get the car centered properly. If you are going to use ramps, I'd suggest picking the car up with a good jack then put the ramps under the wheels. In any case make sure the car is in park with the parking brake on if you put it on ramps. If you want to save time you can then back off the ramps, but WATCH OUT!!! Ramps like to "shoot out" from under the car as you back off them!! I hate car ramps and refuse to use them. Check out this picture: Talk about a death wish!!! When I spotted this car I just HAD to get a picture of it! I call it the CAR OF DAMOCLES !
Thank you for visiting the ECONOMECHANIX WEB SITE. Please feel free to comment. We also serve the surrounding communities of Alachua, High Springs, Hawthorne, and Newberry! Gainesville has been my home since 1974, and I've loved Gvl and the Gators since I came here in the fall of 1974 to attend the University of Florida. I loved it so much I stayed and opened my car repair business. Originally it was out of the back of a 1963 Chevrolet wagon, but in 1977 a fellow mechanic and I opened an auto repair shop with actual walls, etc. I stayed in the same location for 26 years, and recently moved my operation to property I bought 15 miles east of Gainesville. I am doing most all the repairs myself now, having reduced my overhead from $1500 per month to practically nothing. I do work by appointment only. I mostly work only on my established customers cars, but I will occasionally take on new clients. E-mail me and I will either make arrangements to look at your car, or I will recommend you to someone who will.
George G. Scott, Jr.
ABS: Anti-Lock Brake Systems
ADVANCE: Car ignition timing
ALTERNATORS and Car Battery
BAD CAR DESIGNS
BATTERIES: Auto, Car or Truck
BELTS AND HOSES
BODY AND BUMPER REPAIRS
BRAKE REPAIRS: Car or Truck
Car Washing and Care
CARBURETORS:Car & Truck
CHECK ENGINE LIGHT
CLEANING: Engine Cleaning
CLUTCH REPAIRS: Car & Truck
COMPRESSION: Car Engine
COMPUTER CAR CONTROLS
CV JOINT OR CV AXLES
ELECTRIC WIRING REPAIR
ENGINES: Car & Truck
FUEL AIR MIXTURE
FUEL INJECTION: Car & Truck
FUEL PUMPS: Car & Truck
GAGES AND "IDIOT LIGHTS"
GASKETS AND SEALS
GLASS: WINDOWS AND WINDSHIELDS
HEADS & HEAD GASKET
HOSES AND BELTS
"IDIOT LIGHTS" AND GAGES
IGNITION TIMING: Car & Truck
AUTO JACKS: lifting cars safely
LEAN "Car runs lean"
LIGHTS: WARNING OR "IDIOT LIGHTS"
Limp Home Mode
NO START: Car Won't Start
OIL: What's right for your car?
OIL LIGHT ON OR GAGE LOW
RADIATORS: Car and Truck
RICH: Car runs rich
SEALS AND GASKETS
SERVICE ENGINE SOON LIGHT
STARTERS: Auto, Truck
TIMING: IGNITION TIMING
TIMING BELT & TIMING CHAIN
WARNING LIGHTS OR "IDIOT LIGHTS"
Car Washing and Care
WATER PUMP REPAIR
WINDOWS AND WINDSHIELDS