Is my working area safe?

Question

I'm fairly new to wrenching and I'm looking for feedback on whether my outdoor setup seems safe.

I have a gravel driveway area in my backyard where I want to jack my car up and go underneath safely (i.e. pull a transmission, diff, etc).

In my opinion, I'd say this patch of driveway is 'very flat', however it's still not a perfectly poured concrete garage floor, and is also covered in small gravel.

I jacked up my car and gave it the 'shake test'. I shook it hard as hell. As hard as I could without getting a running start. And everything actually felt really solid. But, I'll admit I noticed very minor flex in things (perhaps because all of it is sitting on wood, on gravel, and on a not-absolutely-perfectly flat patch). Maybe this is normal even on perfect concrete?

At a maximum, the slope in this area doesn't seem to be more than ~2% over any stretch.

I'm using 4x '3 ton' HF steel jack stands to support a 1.5 ton overall car. The jack stands are placed on 12" x 12" x 3/4" pressure treated plywood, on the gravel.

Below is a picture of the driveway area in question, with the car up on the jack stands.

Thoughts on whether this seems safe? My backup plan was to build wooden wheel cribs for each tire. I assume the larger surface area and more solid construction would be safer, hopefully in spite of the imperfect ground. Or maybe there's another recommendation that would work? (Perhaps some style of ramps?)

Thanks!

Answer 1

No, I do not think your setup looks safe.

Practical recommendations first, though: I think that ramps are a good idea. I have some that I like very much made of very heavy duty plastic. They have a large footprint so I'm not concerned about a point failure tipping over my support. I think I got mine from Amazon and I certainly didn't pay big money for them.

However, to use ramps effectively, you're still going to have to solve some issues:

1. The ground is just dirt. As I look at that picture, I already see some settling around those squares of wood. That's worrying. Is that well-packed foundation-supporting substrate or just random yard fill dirt (I'm guessing it's the latter)? If it wasn't laid down to take the load, there could be anything under there and it could react to weather and loads in unexpected and surprising ways. Example: a hole in my backyard just opened up because there was a tree in that spot about 30 years ago. The remnants of the stump finally rotted away and now I have a one foot deep hole that would swallow one of those squares nicely.

2. Wood is no good. The load on those squares is not an evenly spread weight. It's concentrated under each one of those jack stand feet. That may not seem like a big deal until you hear the crack as one of those feet finally finds a stress fracture to exploit. Full disclosure: I've heard that sound when I've done this in the past. It's a scary sound and I got out from under the car without dying because the wood gave me warning that it was about to fail.

My suggestion would be to look into some ramps. If you can't find a concrete pad to work on, you could potentially put those ramps on much larger sheets of plywood. That would solve the point load problem while also reducing the risk of settling (a 4x8 sheet of plywood is unlikely to disappear into the earth without warning...).

Answer 2

I'm not seeing an issue here. I'd have no issues crawling under this vehicle the way it's setup to do work. I've done it under a lot more sketchy looking situations (stupid sketchy, which I'd never do again), but what you've got going on looks solid, especially since you've given it the jiggle test and it hasn't budged.

Obviously, none of us are there to truly assess your situation, so you'll have to make the call. It all comes down to how safe you feel it is. You may also want to take into consideration what type of work you are doing on the car. If the plan is to do brakes on all four corners, there's absolutely no issues here (because you most likely wouldn't be under the car). If you are planning on pulling the tranny or differential out, it may be a different situation. Best advice I can give is to be aware of your situation and surroundings, then go from there.

Answer 3

That picture makes me super nervous. You could probably get away with this set up, but you shouldn't. Looks like your jack stands are lined up true. One of those pieces of wood slides 1 inch the wrong way and you are looking at a really bad time.

I see 3 reasonable options. 1)Keep your set up the same and chance it. You will prob be nervous the entire time and won't be worth it.

2) modify your current set up. Grab some cinderblocks or construction grade brick and stack it as high as you can near your jack stands. Fill the remaining gap with some pieces of wood so it's almost flush with the lift rail. Cinderblocks would be better because they would be less likely to roll around on thoes tumbled stones your driveway is rocking. If a jack stands slips it falls a couple of centimeters on your backup stack and you have time to get out. as a helpful person pointed out, cinderblocks will break from impact. The idea is to get it as flush as you can and set it up so if a jack stands fails it transfers the load of the car, not fall a few inches then land on the cinderblock

3) get some ramps. They may not get your car high enough. May have to shop around.

Have fun with your project -