Vehicle On 4 Jack Stands ... Safe?

A couple weeks ago I heard someone on the radio show mention supporting a vehicle with four jack stands, one at each “corner”, apparently by lifting one end with a jack, placing two stands, then doing the same at the other end. I don’t remember if this was mentioned by Tom or Ray, or a caller, but I was left with the impression that it is an acceptable way to support a vehicle while working beneath it. Is this safe and if so, are there any other precautions you need to take? (I would probably also support the end I was working beneath with the floor jack.) Until now, I have always chocked one set of wheels, front and back, lifted just one end of the vehicle, and supported that end with two jack stands and the floor jack. I use 6-ton double-locking jack stands with 9" x 11" rectangular bases. If I had four of these under the vehicle, should that make it stable enough to work safely underneath it? I mostly work on a 1995 Toyota Corolla, sometimes on a 1998 Isuzu Trooper and a 2003 Saab 9-3.

There’s no such thing as 100% safety when working under a car. But 4 good jack stands and the jack as backup where you’re working is about as safe as you can get without installing a lift.

"... I use 6-ton double-locking jack stands with 9" x 11" rectangular bases." ...

With four 6-ton jack stands you could support 24 tons. And you are asking if it is safe? Sheesh!

6-ton double-locking jack stands? I would live, eat, sleep under such support.

Mechaniker, I hope you don’t think that “Sheesh!” comment made you sound intelligent, superior or - god forbid - helpful. I well understand the physics of VERTICALLY supporting a non-moving load. My 3-ton floor jack, with one point of contact, will support the vehicle … as long as nothing moves. My concern was about the danger of unplanned-for horizontal forces causing the vehicle to twist or tip the vehicle enough so that it might FALL OFF the jack stands, since it would no longer be stabilized on one end by four wheel chocks and two rubber tires in contact with the floor. Here’s my suggestion. If all you want to do is demonstrate your superior knowledge, while providing no visible assistance, do it somewhere else.

shadowfax, Thank you so much for your thoughtful comments! Anything to add based on my more clear explanation of my concerns?

According to the instructions that came with my DIYer jack stands, it’s only safe to use two at a time (one end of the car at a time). That’s why I only have one pair. In terms of safety, four jack stands should be able to hold the weight safely, but the car might be unstable if they are normal DIYer jack stands, and not professional grade with a very wide base to prevent tipping.

I use DIYer jack stands for my brake jobs, and I don’t know of a central point to place my floor jack to lift the whole front end or the whole back end, so I do it one side at a time. Sometimes, as I am jacking up the second side, the jack stand on the other side will tip slightly. It’s pretty scary when that happens, but it settles back down when I lower the car onto the other jack stand, and I always give the car a good shove from each side to make sure it is stable. I just can’t imagine jacking up the back end while the front end is on jack stands like that (or vice versa).

I think if I wanted to get all four wheels off the ground, I would use heavy duty ramps in the front and professional grade jack stands in the back, or I would hire someone with a lift to do the job.

I can’t think of anything I would want to do to my car that would require all four wheels to be off the ground. Perhaps if I wanted to install my own exhaust system, I might, but a job like that, or replacing brake lines, I would probably leave to a professional.

Whitey, Thank you. You addressed exactly my concerns, right down to the fact that the only reason I want to do this is to replace most of my exhaust system. I have a pair of ramps, but they don’t raise the car very high. I only use them to get it up high enough so I can get a floor jack under a good lift point. The jack stands I use are Torin 46002A “Big Red Pro Series”. I don’t know if that makes them truly professional grade. What do you think?

After I lift my vehicle, I always give all 4 corners a good shake. I figure, if the vehicle is stable enough with my 230 pushing on it, it’s unlikely something I don’t know about will get near enough to knock it off the stands.

I also tend to go back around, if any stands moved, and re-align them.

It works for me, anyway.

chaissos, Thanks. I guess maybe I’m just a belt and suspenders kind of guy. I do the same thing you do. Then I whack the base and the top of each jack stand with a BFH (big fat hammer) to see if they move around any. Then I shove each corner of the car again just for good measure.

In terms of risk vs. reward, if I were in your shoes, I would look for a sale on exhaust systems, or a coupon, and try to find one at a reasonable price that comes with a lifetime guarantee, and have them install it.

Doing this job yourself might keep you from having to pay for labor, but if you keep the vehicle for a long time, and you have to do the job again, you will have to pay for parts again. If that happens, you might have come out ahead financially by getting something with a lifetime guarantee and paying for labor upfront.

Using 4 good jack stands is fairly reliable but it certainly is not a 100% guarantee that the car won’t come down on you. Murphy’s Law is always present.
Full size automotive lifts in shops do fail and cars have been known to fall off of those too. (I’ve actually witnessed several lift accidents.)
When using jackstands I would recommend keeping the jack in place too.

For some reason, the system isn’t letting me edit my post.

I just looked up your jack stands, ( )and I don’t think the base is wide enough to use on all four points safely. Those don’t look any wider than the ones I use.

Also, I should have said “lifetime warranty,” not “lifetime guarantee.” If you can, look for an exhaust system that comes with a lifetime warranty on parts and labor, but if you have to, settle for one that has a lifetime warranty on parts only.

roddhall, — I hope you don’t think that your comments made you sound intelligent, superior or - god forbid - helpful. Sheesh, lighten up!

9" x 11" stands are bigger then the basic stands sold at AutoZone etc.
The ones I have are more like 8" x 8" (don’t have them handy right now).
And like Whitey I only use one or two at a time.

Mechaniker, I’ve had 14 comments on my original post, two of which came from you. May I politely suggest that you review the other 12 so that you might understand what a thoughtful, helpful, useful comment looks like. They all indicate an attempt to understand my concern, think about it carefully, and respond thoughtfully. Some people even took the time to do some independent research before responding. Your two comments can be summed up as, “Sheesh!” I hope you’re not a professional mechanic; if you are, your inability to deal respectfully with people who ask you “dumb” questions no doubt explains why you are spending your time posting on a website instead of actually fixing vehicles for actual customers.

If the jackstands are good quality, properly pinned, rated for more than the weight they’re holding, and on a level and solid ground (like a level secion of paved driveway) than they’re perfectly safe. The biggest danger with stands is when improperly used, like cheap stamped metal stands on grass.

Personally, I like to back them up with the jacks, but in all honesty I don’t think it’s necessary if they meet the aforementioned conditions.

When working under only one end of a vehicle I prefer ramps, again properly used on a hard level surface.

The car will rest on the top of each jack stand. I don’t see anything to secure the stand to the car so it’s possible the jack could slip and bring down 1 or more corners. You’d want to make sure that each stand was somehow secured to the contact point on the car.

Is there any way you can connect the 4 stands to one another, possibly using something like steel fence posts? This would add stability by preventing the stands from moving independently. A steel collar on the end of the post attached to the stands would make it kind of a box.

Personally, I never get under my car without taking a cement block with me. I figure if it’s going to fall at least it won’t totally crush me.

I still can’t edit my posts.

My largest concern about using four jack stands is the danger of getting the car up on all four of them safely. In order to use four, you have to lift one end of the car while the other end is already on jack stands. That is probably the most dangerous part of the process, so make sure when you do it, you are not underneath any part of the car, as it could fall in any direction if the lift point you are using on the car collapses or bends, or if the car slides on one of the jack stands while you lift the other end.

In addition, the higher the jack stands are set, the less stable they will be. If I am just getting my tires off the ground to do a brake job, I don’t have to set them very high. If I am trying to do something under the car, I set them as high as I can for maximum clearance, and that adds to the danger. In fact, that’s when I usually notice the jack stand tipping slightly, as I mentioned above. How much room do you need to replace your exhaust system? How safe will you feel jacking up one end while the other end is up on jack stands set that high?

When you have 2000+ pounds of car pressing down on a jack stand, it’s pretty hard to get it to slip off. That’s a LOT of static friction to overcome. It isn’t impossible (which is why you put the jack where you’re working as backup) but it is unlikely. Having looked at the stands in question (they are NOT professional stands, btw - - “Pro” is a marketing buzzword that has no actual meaning), they’re not bad. Certainly better than a lot that I’ve seen. I do agree with Whitey, however, that the higher you raise the car, the more danger you’re in, and I also agree with him that the bases are a little narrow. You’d probably be fine, but there is an element of risk.

When replacing an exhaust, oftentimes all you need to do is get the front in the air - the rear part of the exhaust is supported by rubber hangars that are usually pretty easy to get to when the car’s flat on the ground.

I’ve used four jackstands as support under vehicles for years. As an example, it’s impossible to remove a manual transmission from an F150 pickup to replace the clutch unless the truck is on 6 ton jackstands set at their highest level. Otherwise the transmission can’t be removed from under the vehicle while sitting on the transmission jack.

As mentioned, once the vehicle is atop the jackstands, shake the vehicle to check for stability before going under the vehicle.