Concerete Slab Question

[Bingster]

If a concrete slab is an inch off level lengthwise toward the rear of the car, does it makes any difference when jacked up?  The width of the slab is level.

[busycoupe]

My old garage did not have drain in the floor, but was sloped slightly towards the door, about 2 inches over 20 ft.  I never had a problem jacking up the car or working on it on jack stands.  I did always chock the wheels when jacking one end or wheel off of the ground.

[Eneto-55]

An inch is not much at all in 16 - 18 feet.  The assumption is that you would use jack stands, so you would have adjustment there anyway.  I don't know if you're talking about having it on 4 stands, or just at front or rear, but I generally only put the jack stands under the end where I'm working on. and that makes a lot more slant than a slight slant in the floor.  I know I should also use wheel chocks, but I'm not so good about doing that.  Good reminder.  (But I do also always leave the floor jack under one side, just in case.  I figure that might save me if a jack stand collapsed.)

[Mortimer452]

You would need a lot more than an inch to cause any problems safety-wise with lifting up the car.

[Bingster]

Thanks, that's what I thought.  Two jack stands, at the end I'm working on.

[rallyace]

The angle of the floor is less than 1 degree. It will not pose any type of issues. When using jack stands, I always block the wheels still on the ground and keep the jack about 1/4" under a frame rail if possible when working under a car.

[pflaming]

Similar to rallyrace, after I set the car on the stands, I try to shake the car off of them, that eliminates the tops being on an  angle. Then I raise the jack just enough to have tension.  I had my truck come off the jacks when I was under the front axle. I was fortunate I had rims on, but I still got a good squeeze and I had to wiggle my way free. It is an experience I will never forget. It happens FAST!!! 

[MackTheFinger]

I've gotten more cautious over the years, especially since a friend died when a SnapOn air jack popped and dropped a Lincoln Town Car on him. We had a mutual friend who had a junkyard and he was always yelling at his help for not being careful enough. Like he said, it only takes a minute to throw a couple of wheels under a car and it could save your life.  

[DrDoctor]

   I always put wheel chocks on both sides of each wheel left on the ground, so the car can’t roll forwards or backwards. My wheel chocks are actually airplane wheel chocks—angled edge against the tire, so it’s a tight fit. And, when done, a quick tug on the rope pulls both of them from the tire.

   A few extra minutes for safety sake at the beginning of a task—or a lifetime of regret, or worse yet-a life lost. I think the few extra minutes spent up front are well worth it.

[classiccarjack]

When I built my driveway, I put a 1 inch slope over 20 feet.  If nudged, my modern cars will roll.  My heavier older vehicles do not.  

I had a Mustang 2 fall on me when I was 21 years of age.  The jack stand (3 legged) slipped, and the car then moved over, and caused my floor jack to slide out from under the car.  My head was pinned between the frame and the floor. I was able to blindly get the floor jack back under the car to get free.  I have not used a 3 legged jack stand since that day.  Unfortunately, that was all that they had at the hobby shop on base in Germany.  I swear that if I had the engine in the car, I would have suffered major head trauma or died.

Even being careful, the worst may still happen....  But then, why would a company make a 3 legged Jack Stand?  Not a kind Company for sure!  

[desoto1939]

Had a good friend that has a 35 desoto airflow. He was a Chrysler technician. He was taking off the manifold and had the car up on a bottle jack and by accident hit the bottle jack with his foot and the car came down on his arm and cut very deeply into his arm down to the tension. He had to have skin grafting and was lucky that his arm was able to be repaired. He still can use is arm but now he is even more careful.  He said to me that he knew he should of had the car on jack stands and with a floor jack under the car but as we get older we get less careful when working on the older cars.  So take heed on this gentlemans experience and play safe at all times when working on our old cars and trucks.

 

Rich Hartung

[DrDoctor]

   I’ve been pondering this slope of the concrete floor issue. About the only time a floor has to be absolutely level is, for example, if you’re putting a new clip on a frame. If the floor is slightly off, you can use an adjustable level, by setting it at “zero bubble” on the floor, and then using it in the same orientation for the remainder of the task. Of course, a frame table with a jig is perfect, but who can justify that expense for something done very rarely by the average guy??? Typical floor slopes done pose much of a problem with putting a car in the air on stands, as long as (as discussed herein) the wheels at the other end are SECURELY blocked, and the jack stands are sturdy.