Which part of the pinch weld is the strongest?

[johnnyh55]

So I have experienced a few pinch welds that have bent while jacking with a floor jack over the years and I think the fact that the welds were rusted didn't help but I started searching online on how to jack from the pinch welds with a floor jack and noticed that a couple of companies and a lot of people make their own pinch weld adapter from a hockey puck or a piece of steel. So with these adapters, it looked like the pinch weld went into the center groove of the adapter and the lifting force was applied to both sides of the pinch weld on the rocker panel. But then I seen this video, which says to jack right on the pinch weld with their adapter since it's the strongest point and not both sides of the pinch welds like I was thinking

Video

So my question is, should the lifting force be applied to the pinch welds or on both sides of the pinch welds on most cars? I looked at my factory jack in my 2006 Chevrolet HHR and it looks like it applies force to both sides of the pinch weld.

 

[Cujet]

I think it depends on the vehicle. My Honda S2000 is made from the softest sheet steel sheet metal mankind has ever produced. I can bend the pinch welds in my fingers. AND, the metal is not that thin! That car simply cannot be lifted by the pinch welds without deformation, regardless of the method.

 

[IndyIan]

Usually there is a marked spot on the pinch weld where the scissor jack is supposed to go. With a floor jack I find the next spot in where there is 2 or 3 layers of metal, the same spot they use when the car is put on a lift. I put a small scrap of soft wood on the jack too to keep it from scratching things up.
You can also use a piece of softwood under the pinch weld to spread the force out and not scratch it up.

 

[CharBaby]

I am offended that the auto mfg's have designed these pinch welds as an actual place to lift a vehicle...Really? As anyone who lives in the salt belt can attest to, these pinch welds get beat up from lifting the vehicle with the DIYers floor jack or the dealer or garage lift. And over a short period of time, the metal & welds are completely destroyed.

Some of the newer designed lifts do a better job of NOT destroying the metal & welds however not all shops have replaced their ancient lifts with the new design which is a very costly upgrade. And we often have careless techs doing a poor job of lifting our precious vehicles.

I almost never use the pinch welded area when lifting a vehicle unless absolutely necessary. I look for the best/strongest place to lift the vehicle although not all vehicles allow for this. And I always recommend using a rubber cushion or your favorite home made devise/item when lifting your vehicle with your floor jack. I never use the vehicle's provided jack unless I get a flat tire out on the road(once in 45 yrs).

 

[OldSparks]

I think the area adjacent to the pinch weld is where the jack should contact the vehicle. I bought this rubber puck, but it only works for my son's Mazda 3 - the jacking point on my Honda Civic requires a different shaped puck. It fits well on the saddle of my Princess Auto floor jack...

 

[doitmyself]

LOL, this question comes up often. I'm glad I am not the only one scratching my head on this.

The real problem on many of today's cars is that once you choose your jack point, where do you place the jack stand?? I've managed to get it done on my vehicle, but I can't explain how I did it. Just an "educated" guess.

 

[johnnyh55]

Originally Posted By: doitmyself

The real problem on many of today's cars is that once you choose your jack point, where do you place the jack stand?? I've managed to get it done on my vehicle, but I can't explain how I did it. Just an "educated" guess.


There is these floor jacks that exist to address this problem:

In the USA:
Jack point jack stands

In Canada:

The Jack Stand Lift Mate

They allow to jack your vehicle with a floor jack and then put your jack stand right through the floor jack saddle groove and then you lower the car on the jack stand at the same spot where your floor jack was.

I have never tried them but they look interesting.

 

[johnnyh55]

Originally Posted By: OldSparks
I think the area adjacent to the pinch weld is where the jack should contact the vehicle. I bought this rubber puck, but it only works for my son's Mazda 3 - the jacking point on my Honda Civic requires a different shaped puck. It fits well on the saddle of my Princess Auto floor jack...

The reason this puck works without bending the pinch weld, is it because it spreads the load across a wide area on the pinch weld or because no weight will ever be supported by the pinch weld, it will just go through the groove and the weight of the vehicle will be held by both sides of the pinch weld?

 

[stephen9666]

As noted, depends on the vehicle. On some, they're designed with a reinforced spot on the weld, so you're supposed lift there, not on the rocker next to it.

A hockey puck or rubber pad helps in any case because it provides cushioning and spreads the load.

 

[doitmyself]

The question will never be answered. There is no consensus whether the entire weight should be supported directly on the pinch weld, on the horizontal metal directly next to the pinch weld, or a combination of both.

The next problem is that pinch welds have different heights and the pucks have different depths. Some people claim their OEM tire jack only contacts the pinch weld bottom while others claim their OEM jack groove allows contact on the metal next to the pinch weld.

In a perfect world, I think that the puck should be sized to your particular pinch weld so that when it compresses, about 80% of the weight is supported on the pinch weld bottom and 20% on the metal directly next to the pinch weld. This would cradle the pinch weld very tightly so that it cannot bend.

We now need to create a perfect world.

vs.

 

[ArcticMan]

I never lift from the pinch welds. I always lift the car from the subframe or the suspension. Jack stands go on the lower control arm mounts, or typically the subframe. In the rear, I will sometimes use a flat spot on the body. But never the pinch welds.

 

[OldSparks]

Originally Posted By: johnnyh55

The reason this puck works without bending the pinch weld, is it because it spreads the load across a wide area on the pinch weld or because no weight will ever be supported by the pinch weld, it will just go through the groove and the weight of the vehicle will be held by both sides of the pinch weld?


On my son's Mazda, it spreads the load - I don't even think it contacts the pinch weld - just the area around the pinch weld.

OTOH, my Honda Civic has a plastic rocker panel and this puck, because it is 5 inches wide in diameter, would likely put too much load on the plastic rocker panel.

 

[KrisZ]

I hardly ever use the pinch welds and they look brand new on my 11 year old Mazda 3, granted I oil spray them. There are plenty of other structural supports on any vehicle that the pinch welds don't have to be used.

 

[JHZR2]

I use a puck with a groove cut out.

 

[IndyIan]

Originally Posted By: KrisZ
I hardly ever use the pinch welds and they look brand new on my 11 year old Mazda 3, granted I oil spray them. There are plenty of other structural supports on any vehicle that the pinch welds don't have to be used.

+1 I think they are really only to be used with the scissor jack in emergencies. No shop has ever use the pinch welds to raise any of my cars that I know of.

 

[Silk]

They bend because a floor jack lifts in an arc, if you use the supplied scissor jack they don't bend, they also don't bend using a hoist (lift). Using a floor jack is the problem.

 

[bmwpowere36m3]

This is why I prefer European cars with integrated lifting pads... However I've always just placed the lift arms on the pinch weld, usually a spot near the frotn and rear where the pinch weld is thicker (multiple layers). The lifting arms on the 2-post have flat rubber pads.

I agree with the guy above regarding most jacks. I've definitely seen some gnarly pinch welds...

 

[eljefino]

Originally Posted By: Silk
They bend because a floor jack lifts in an arc, if you use the supplied scissor jack they don't bend, they also don't bend using a hoist (lift). Using a floor jack is the problem.


Also if you use a lift you have the front overhang leveraging the rear upwards using the front lifting point as a pivot. The firewall lift pads see the vast majority of the weight. The center of gravity of a FWD car is only a couple feet rearward of the firewall.

If you try to lift one corner at home, it gets more weight.

Some/ many cars have "fangs" stamped into the pinch weld to indicate that the emergency jack goes there. They tried to standardize on triangles, to middling success.

The rear trailing arm mount on FWD unibodies survives longer than the rockers tend to.

 

[JTK]

The key is, they're designed to be used only with the style of scissors jack that came OEM with the vehicle, or with a garage lift with lifting pads made to accommodate the pinch welds. Cram your floor jack against them and things are going to bend.

 

[sleddriver]

Originally Posted By: johnnyh55
...my question is, should the lifting force be applied to the pinch welds or on both sides of the pinch welds on most cars? I looked at my factory jack in my 2006 Chevrolet HHR and it looks like it applies force to both sides of the pinch weld.
Depends. The video link you posted doesn't show much shoulder on either side of the pinch weld. The sled has a wider surface to spread the weight on either side.

The factory jack attaches to a rod allowing one whole side of the car to be lifted. There are arrows stamped fore and aft on the underside indicating where to jack on the pinch welds.

I use a piece of 2x4 SYP with a slot cut perpendicular to the grain.