Okay, usually I'm pretty good with where to place jack stands underneath cars (just in case the jack ever fails ya know....) but lately I've noticed on the seven that if I place the jack stands under what I think is the frame rails under the floor pans and lower the weight of the car onto the stands, the frame rails start to deform under the weight.

So my question is, where exactly should I place jack stands so as to avoid any frame bending (even if it is
only a little bit)? On the rear it is easy enough to just place them at the lower control arm connection or even under the axle depending on where I am working. On the front, I am unsure.

 

If you put them at the very front of the frame rails before they turn upward around the firewall, the metal has more layers in that area.

 

how about lower arms and rear end
pending on what kind of work your tring do

 

Okay, I'm dumb...where would I put the jack then? I use a 3-ton roll around floor jack and that is usually where I put it at to jack it up. I just don't trust the little scissor jack and I don't trust putting a jack under the suspension arm (I'd call it an A-arm but it really isn't an A in our car, hehe) since it looks pretty weak to being with.

 

You should say what kinda of work your tring to do,cause you shouldnt jack it on the rear if your doing brake/tire work etc etc..

 

alien, you dont mean the upward sloping piece in front of the LCA attach point? I did that ONCE! when I jacked the front up, it slipped down that slopped piece and fell !

Places I use
On the "frame rails" there are 2 places on each one front and back where the metal is doubled up, its a good place ( I think thats what buttlips was talking about) . I've also put them on the lower shock eye. And also have put them under the tension rod brackets in front.

 

The little scissor jack works great when you use the recommended lifting points. I usually put a long piece of wood between the jackstand and the frame rail to spread the weight so the rail doesn't get deformed.

 

Thanks for all the tips guys.
Rx7Carl: Never on any slopping pieces, too dangerous.
SoRRoW: Right now just odds and ends, checking for rust, getting ready to remove the engine, stuff like that. On the rear stuff, removing the whole axle wheel to wheel...that was on the parts car though, so it didn't matter if I bent the frame rails on it.

 

Best rule of thumb is place jack stands on beefy metal - engine subframes, axle housings, etc.

The 'frame rails' are actually C-channels - basically more sheet metal bent and tack welded to the floorpan to create a lightweight 'box section' to give the floorpan more rigidity.

I've seen tons of C-channels on Japanese cars (Nissan/Datsun Z cars as well as ReXes) with puckered C-channels from someone using them as improper jack/jack stand points.

Once the C-channels are puckered they have to be removed and new ones welded on in order to maintain unibody structural integrity. Puckered C-channels won't pass most safety inspections and, far more importantly, can cause the passenger compartment to buckle on impact rather than the front or rear crumple zones.

 

Anyone have pictures? ...just show where you think they should put the jack stands.

 

here is some pics.. i usally place em where the metal is doubled over..

 

djmickyg, first pic looks good, but looks like you missed the mark on the second. Looks about 3-4 inches too far forward! Where the 2 "frame rail" pieces overlap is the strongest part.

 

Like Manntis already mentioned you shouldn't place the jack/stands under the frame rails as they buckle quite easily. If you must then it's a good idea to distribute the load with a block of wood.

For the front end I normally use either the crossmember or the forward tension rod brackets. For the back it's either the diff or the lower trailing arm pickup points.