IXLR8

After a couple of years of going back and forth trying to decide between a scissors lift and a two-post lift, I went with the MaxJax Two Post Portable Lift. The MaxJax was chosen because I wanted unobstructed access to the bottom of the vehicles I would be working on. The lifts each have their advantages and disadvantages.

Either choice of lift would have had me do some concrete work.

• A scissors lift is too tall to drive over, so it either needs to be placed below grade or driven over by placing 2 x 12 lumber where your track is. The advantage of a scissors lift is that the residential-grade concrete floor would be less of a concern. It along with the 2x12 lumber scenario is by far the easiest & quickest solution. Two very nice below-grade installations by gtroth and Magdaddy are shown in this Rennlist thread, Center of gravity relative to lift points.

• A two-post lift needs to be anchored into the concrete floor. I didn’t trust my residential-grade concrete floor enough to bet my life on it. And sure enough, after cutting my concrete slab, I am glad I didn’t.

Having decided upon the MaxJax two-post lift, I wanted to see one in action as well as their installation. For what I plan to do and the number of times a year I plan to use my lift, the MaxJax was perfect. As for a full sized two-post lift, another local 993er has one and I wasn't able to stand up straight under it.


MaxJax column spacing:
How far to set the columns apart? The MaxJax manual provides recommendations on column spacing, but I wanted to see how a 993 would fit best. To the outer edges of the MaxJax base plates, one local 993 owner had them at 120 inches apart and another local 993 owner had them at 132 inches apart. Having had the opportunity to measure the arm extensions of the MaxJax at the 132 inch column spacing, they were extended by ~50% with the 993 centered. I ended up choosing 130 inch spacing for my install. See * below.


MaxJax column location – front to back:
I have a standard sized two-car garage measuring 269 inches deep. Not wanting to use the MaxJax column as a door stopper, I placed the MaxJax columns more towards the front of the garage or 104 inches from the front wall of the garage to the center of the MaxJax column. With the 993 centered with respect to the MaxJax column, I have two feet from the front wall of the garage to the bumper. Centering the 993 center-of-gravity-wise *, I have a foot between the front wall of the garage and the bumper and lots of space behind the 993 for an engine/transmission extraction.

* Note, with 130 inch column spacing and with the 993 centered at the approximate center-of-gravity point relative to the MaxJax column, the forward arm of the MaxJax is nearly fully extended and the rearward arm of the MaxJax is nearly fully retracted. If I had spaced the MaxJax columns further apart, that would not have been possible.


MaxJax anchoring:
Not that I planned on using them, there seems to be some contradiction between instructions in the MaxJax manual itself and the Wej-It Power Drop anchor instructions.

From the MaxJax manual: “The floor on which the lift is to be installed must be 4-¼ inch minimum thickness concrete, with a minimum compressive strength of 3000 psi, and reinforced with steel bar”. My concrete floor may have been 4-¼ inches thick...here and there, but I don’t know of any residential garage floors that are “reinforced with steel bar” unless it was an owner request prior to construction.

From the MaxJax manual: They state, “drill hole approximately 5½ inches deep”, yet my concrete slab only needs to be 4¼ inches thick?

The Wej-It Power Drop anchor instructions list other numbers again.


Custom MaxJax anchoring:
I won’t go into the details here other than to say that I went overboard by choice. My method of anchoring is my choice and I'm not suggesting that anyone else use it. Further details can be found at this link.


December 14th:
Having confidence in my installation, my 993 was the first to be used for the initial test run.

P-daddy

Very nicely done Alex. Planning/prepping is key. Are the boards for clearance?

UserA

Holy crap, I just read your anchoring page. I want you engineering my next house.

Mike J

Nice job Alex! A bit over-engineered, but kudos for that. Interesting on your extending the floor plates, my two post already has those large footprints do I did not bother.

Your lift is a bit noisy on the way down - could not tell if its the fluid whining through the pipes? Mine is dead quiet, but the two post uses balancing cables between the two posts so that may impact the hydraulics (since it's a simple valve on mine).

Detailing is a pain now because you can see all the defects in the rockers and lower quarter panels that you would normally not see at all...

cheers,

Mike

IXLR8

Isn't it always. Automotive paint jobs come to mind.

Garages are normally sloped for runoff and the MaxJax is to be installed level. I just wanted the jack pads to contact the lift pads all at the same time, instead of the front lift pads before the rear lift pads. The 1.5 inch difference isn't a big deal though.

I have so much clearance (about 3 inches) even when using my jack pads that I can eliminate the front boards and just use two stacked boards in the rear.

What I am going to end up making are parking pads with stops placed where I want my 993 to locate for lifting purposes. I'll mark the concrete for them and just place them there when needed.

Paul902

I saw the floor plates and hole in the concrete when I was over picking up ignition wires. Very impressive. Alex is not one to do anything by halves.

IXLR8

No kidding, Mike. During the lift, I was more worried about the MaxJax failing.

I even have M16-2.0 12.9 grade socket head cap screws holding it down with lots of anti-seize due to using stainless for the anchors. The fasteners are zinc plated steel.

The MaxJax plates are 13 x 14.5 inches. The 18 x 18 inch stainless steel plates just gave me more surface area to slide the lift into position. I doubt I'll be moving it although the option is there.

You don't want to know what I've got in all that stainless steel, dollar-wise.

I hadn't lubed the sliders with white grease yet. It made a very slight noise going up and a bit more going down, especially at the end when the boards rubbed during the wheels settling.

It'll be easy to do that complete power steering flush now.

Kein_Ersatz

Just ordered a lift from Costco ($300 off and free shipping to a forklift location ended Sunday).

Great timing of post :-) Expect to do install this spring.

osugasman

Alex: Awesome!! Great job on plan and execution. I will most likely look to copy the 130" of offset between posts so that I can maximize the center of gravity positioning.

Thanks for posting. Brian

IXLR8

Drill a test hole where you plan on placing a column to see how thick your slab is. If you have doubts, at least you can pour some 3 x 3 or 4 x 4 slabs in advance to keep your installation time down.

initial

It may be over engineered, but its definitely the install I would want.

Excellent work! Any thougts on what the weakest point may be?

IXLR8

The stainless steel anchors. For every advantage there is a disadvantage. Corrosion resistance vs strength/characteristics of the metal. I'm always concerned when there is a sharp edge (the threads I cut) in steel.

The smooth skin of the anchor in comparison to that of rebar, which is why I TIG welded extra anchoring on.

As for the MaxJax, the way I understand it, there really is no safety devices built into it. For example, it not locking every 4 inches on the way up should a seal on the hydraulic cylinder fail, or having a slow hydraulic bleed in the case of a hydraulic line failure.

Kein_Ersatz

Yup. already did test drill, all good.

Was going to get the shipping to a friends business w/ forklift and manhandle from there to my garage. Got a call from Dannmar about delivery, lift gate drop off is included in Costco sale price, so direct drop ship to my driveway no extra charge.

IXLR8

Same here. I was both surprised and happy.

Its about 900 pounds. Moving the crated MaxJax on your own can be a bit of a challenge. I used two dollies to get it into the garage.

arjag

Very nice Alex, I have been following your thread because this is the way that I think that I will go. I have 8 inches depth of concrete because I can see the pour depth in the stairwell that I had built for entrance to the basement but how do I know the compressive strength?