Daniel5691

I don't suppose I really have a lot of "-phobia" issues to deal with, but if I do, getting a car up in the air and subsequently working beneath it is definitely the worst.

Here's my current approach, certainly not perfect, but maybe better than I've used before.

This is not a "HOW-TO-SAFELY-LIFT-AND-SUPPORT-YOUR-CAR" post. I don't know what I'm doing. This is simply a method I am using.

I lift the car normally, with lift bars, per instructions, with a good heavy floor jack and the heaviest jack stands I could find, a 6-ton HF set. All of the weight of the car is 100% on the liftbars and 6 ton stands, only.

I built 4 rebar-reinforced concrete "tubs" with 5 gallon buckets serving as the concrete forms. The rebar is arranged in a vertical/horizontal arrangement within the tubs, held together with construction wire. There is a LOT of rebar in the concrete. I mixed the concrete to the highest strength ratio, and let the concrete dry for weeks before using them. Above the concrete I have placed pressure-treated lumber to lightly "snug" and fill the space between the concrete and liftbars.

No weight is being supported by the concrete tubs, but the tubs might hopefully afford a wide-based "plan B" should the impossible happen and one of the jack stands fail. I added another set of Craftsman jack stands as well, "snugged" to the lift bars as possible, but again, bearing no weight.


Feel free to critique, correct, comment, disparage, and ridicule.
I hate working under cars.

SeanR

Good news for you is, a 9.7 earth quake could hit and you will be the safest person in the area. Your house may be gone, but damned if your 928 isn't nice and safe up there.

V2Rocket

would probably be a safe spot to duck under in case of tornado.

since 2005 i have used some simple blocks as my preferred stands - got some 4x6 wood, cut it into 12" lengths. put a pair parallel and then stack another pair on top perpendicular to the first pair and glue/nail together. solid/stable, 12" lift height, and you can stack the blocks if you want 24", also gives a nice area to lay a 2x4 on top of to support the porsche frame rails and spread the load.

dr bob

I'd be more comfortable with another set of those stands than the bucket of concrete. Just sayin...

GT6ixer

I can confidently say that death by 928 compression is not in your future.

gazfish

You could dig a pit to work in by the time you've got the car in the air

Alan

As a backup - rotating the tubs 90 degrees would seem to make more sense to me. If the car falls off the lift bars - that gives you more coverage...

I don't know how the car could fall off the lift bars - but you shouldn't ever need this for any other reason either...

lan

NoVector

Do you start with lifting one side up to the 6-ton stands or do you first use the smaller stands to stair-step up to the 6-ton? The angle/stress of lifting one side to clear the 6-ton jack stands and then doing the other side doesn't seem like a good idea. Full disclosure - I know absolutely nothing about engineering other than listening to Wolowitz on Big Bang Theory.

Wisconsin Joe

There's nothing wrong with overkill. If it gives you peace of mind to have that setup, more power to you.

Makes it a bit difficult to get in or out from under using the side, but that's not that big of a deal.

Different people use different things to act as backup support.

Personally, I use the 6T HF stands and lift bars. Once it's up, I cannot make it move, rock, tip, whatever. Not a bit. Even at the highest point on the stands. And I try. My "is it solid?" test has always been to push, pull, and rock the car as hard as I can. If it wiggles, I go back and reset it (this goes for any car in the air, not just the 928 on the bars.

I know there's some ideas posted about the 'tipover force' not being all that high, but the footprint of the 6T stands is pretty wide. And with the car on all four of them (more or less, depends on how perfectly level the floor is), getting the car to fall is going to take some force.

It may be overkill on my part, but when I put it up on the bars, I put in an extra step. One side up partway, other side up all the way, first side up the rest of the way, other side up to take any lateral loads off the stands. I am likely being overcautious, but I really don't like the car tipped that far sideways.

And:
Construction guys call this "cribbing." Look at a big construction site. You will see some pretty hefty stuff being supported on "square crosses" (box cribs) of lumber.

Daniel5691

Vector:

Very insightful question.
In the past, I have always used smaller (shorter) jack stands to sequentially get the car up high enough on the liftbars to allow use of the 6 ton HF stands.
However...
last night as I was going to use that method, I noticed that the back/rear jack stand was supporting the lifted side of the car alone when I lowered the jack initially... the front liftbar point was not touching the front jack stand. The front was too light/ off balance due to the fact that my engine is out of the car. Instead of trying again to approximate the new "balance point" for locating the jack under the liftbar, I very slowly jacked up to the height of the 6 Ton HF stands instead. That worked.
It was not an issue with the second side during jacking. However, after getting both sides up, I did go back to the initial side and gently lifted her back up on the jack to "relieve" the stands of any lateral load... they didn't budge at all.

FredR

You might be surprised to know that the setup is relatively stable even if one of the jack stands collapses. It might wobble but the out of balance force can easily be restrained by light support.

On my setup I rigged a test to prove the theory and it worked as expected. I put a hydraulic bottle jack near the front of the lift beam, jacked it up and removed the axle stand. Replaced the axle stand with a 2 tonne screw jack a bit lower than the stand, placed where the axle stand had been and lowed the bottle jack- the thing did not lower onto the screw jack but with light force I could rock the car as one would expect. I found this quite reassuring.

That being said if I am working under the car I always add aditional back up- usually my two screw jacks and place them depending whether I am working under the front or under the rear.

When lifting the car I raise one side to the point where the 3 tonne axle stands can sit under my lift beam in the fully lowered position. I then lift the other side off the ground three notches higher, return to the other side and lift that 6 notches higher and the return to the other sie to lift it the final 3 notches- this to avoid too much differential lift- so far it has served me well.

j.kenzie@sbcglobal.net

Hi Daniel,
It looks pretty good, but if the car was bumped from the side the lift bars could fall off the 6 ton stands, then not land on either the buckets or secondary jack stands. I would say your system is weak in terms of a transverse impact or force. I would try to develop something to catch the car in that unlikely event.
I think we are talking one in a million here, but that is after all what you are trying to address.
Good luck,
Dave

GT6ixer

And if you are really about being conservative I personally never buy stuff from HF that is intended to keep me from dying. I purchased a set (4) of US Jack 6 ton stands and have the same set up as you minus the concrete buckets and backup stands. The stands use a double pawl design for redundancy. Save the HF crap for your backup.

hlee96

Well Daniel, yours do have plenty of redundancy build in for the sake of safety. However, you're also taking away the "fun" and "adventure" of working on our own cars....
Example:

Daniel5691

Hi GT6 !

I thought about getting the USJ stands, but was concerned about some of the reviews of the welds on the 6T models... http://garagejournal.com/forum/showthread.php?t=181644

I still haven't figured out who makes the 'best' stand.... certainly NOT my Harbor Freight stands, of course... but I'm not clear on where to spend the 'quality jack stand money'....

Dan