Another question for 4-post lift owners

[turbojimmy]

I will readily admit that I have some sort of mental defect where I need to over-analyze things to the point of near-insanity. My latest anal-retentive compulsion is my newly-installed 4-post lift.

My garage floor slopes the maximum permitted 1/8" per foot from front to back. This slope is well within the operational tolerances of the lift (Rotary Revolution) since even though this puts the columns at a slight angle (1-3 degrees) it operates smoothly and hasn't toppled over. This slope doesn't concern me as much as some 'waviness' in the floor that causes the pads on the columns to not be in complete contact with the floor. Not huge variations - 1/16" - 1/8" in most cases but I want to put spacers under the gaps and bolt the columns down. The manufacturer said this is not necessary but I'd like to do it anyway. I've already bolted the left columns down without leveling/plumbing them and they're fine. I feel a lot better about being around it now.

Now the question is: when anchoring the columns down, do I attempt to plumb/level the columns to compensate for the slope of the floor or do I just leave well enough alone and bolt them down as-is?

My concern with leveling them is that when the runways get to the floor I'm afraid they may bind in the columns (i.e., the front of the runways will hit the ground first, followed by the rear because of the slope of the floor. Right now the runways are leveled per the instructions and everything works fine.

Here's what I'm talking about:

1) Column slopes with the floor, ramp is leveled per the installation instructions. This makes a slightly less than 90-degree angle between the runway and the column. It works fine this way and the slope is within the manufacturer's tolerances.

2) Not all 4 corners of the columns are touching the floor due to imperfections in the poured concrete. Lift is still solid, but when there's no weight on it I can rock it a little. This is why I want to bolt it down

So, do I plumb the columns or leave as-is?

Jim

 

[gnxtc2]

Putting a level on the columns will not level the lift. You need someone that has a transit. Eventhough you level the columns, their elevations will be different when you bolt it down. How the lift sits right now, it has the ability to move and unbind itself. Once things are bolted down, weird things start happening.

What happens when the car is on the lift? Are there any gaps under the columns?

If you are so obsessed with bolting it down, I would cut the floor where the base sits and pour a footing that is level and has the same elevation corner to corner.

or

You can put some steel shims under the base, bolt it down and see what happens.

Another thought....

Where the columns are welded to the base, is it totally smooth or did it warp from the heat? Are the bases totally flat? Maybe bolting it down will bend the metal back.

Billy T.
gnxtc2@aol.com

 

[turbojimmy]

Putting a level on the columns will not level the lift. You need someone that has a transit. Eventhough you level the columns, their elevations will be different when you bolt it down. How the lift sits right now, it has the ability to move and unbind itself. Once things are bolted down, weird things start happening.

What happens when the car is on the lift? Are there any gaps under the columns?

If you are so obsessed with bolting it down, I would cut the floor where the base sits and pour a footing that is level and has the same elevation corner to corner.

or

You can put some steel shims under the base, bolt it down and see what happens.

Another thought....

Where the columns are welded to the base, is it totally smooth or did it warp from the heat? Are the bases totally flat? Maybe bolting it down will bend the metal back.

Billy T.
gnxtc2@aol.com

Billy,

Thanks for the reply. I'm not using the word 'level' properly - by 'level' the columns I mean plumb them. Each column has its own adjustment to level the runways. The instructions have you set it on the locks, level the runways using the adjustments at all for corners. Then you get it off the locks (hanging from the cables) adjust the cables so it's level. This way it lifts level and sets down in the locks level. I'm more worried about the 'lean' (plumb?) of the columns. Again, I'm within the limits of the design but I'd rather have it bolted down.

The column bases aren't warped, the floor is (except in one case where I can see the corner of one column is slightly bent - the anchor bolt will draw it down).

I'm going to shim it so that all 4 columns are plumb and see how it operates. If it's good I'll bolt it down. If not, I'll just leave it as is (no shims) and bolt it down.

I know what you mean about letting it unbind itself. When I first bolted down the left front corner it got all bound up. I had to unbolt it and shim the column so it sat as it did before and then it was fine again.

I just have 2 corners bolted down now but I feel much better about it. I'd have to do something really stupid (which is not outside the realm of possibility) to knock it over now.

Thanks again,
Jim