Where do you jack up your Expedition?

[wheelspeed]

So, my Hayne's manual made no comment about where to use a floor-jack to raise the rear end for a brake change, so I raised it from the rear pumpkin.

Now I checked the owner's manual and it says never to do that.

Seriously? That's the most convenient place to jack up the rear by 1000%. The owner's manual actually suggests to jack up a rear axle side. I'm surprised one rear axle tube is that strong to handle most of the weight of the back half of the truck! Plus, that seems like a safety concern to jack up one side, place a jack-stand, let down and then jack up the other side (with all the tilted weight on one jack-stand) until the other jack stand can be put under the new side.

What's the concern with the rear pumpkin? Would a piece of plywood between the jack and rear pumpkin resolve any concerns about jacking under the rear pumpkin? Or, is the pumpkin so weak that it really shouldn't support the weight of the rear of the truck?

 

[GAINMOB]

look on the frame...i have cut-out arrows that show where to lift..then place your stands

 

[FordandPolaris]

I lift by my diff, never have had a problem. I am guessing the manual says that simply for warranty purposes.

 

[tonydiv]

It's actually just a safety and liability issue. It is way more dangerous to have 2 wheels off the ground, than it is to just have 1 wheel off the ground.
Believe me, that sentence in the manual was written by the lawyers, not the engineers.

Jack up the rear by the pumpkin and set a jack stand on both ends of the axle tube for stability. You'll be fine.

 

[qcksnake]

It's actually just a safety and liability issue. It is way more dangerous to have 2 wheels off the ground, than it is to just have 1 wheel off the ground.
Believe me, that sentence in the manual was written by the lawyers, not the engineers.

Jack up the rear by the pumpkin and set a jack stand on both ends of the axle tube for stability. You'll be fine.

YEAP. been doing it like this for years. Just dont put jack on the cover, make sure you slide it up far enough so you dont cause a leak.

 

[Big White]

Just don't jack up a second gen by the punkin!

 

[Captain Morgan]

A picture paints a thousand words.


.

 

[alaskanexpy]

i use the front cross member and the rear pumpkin on the rear.

 

[and0r]

It's actually just a safety and liability issue. It is way more dangerous to have 2 wheels off the ground, than it is to just have 1 wheel off the ground.
Believe me, that sentence in the manual was written by the lawyers, not the engineers.

Jack up the rear by the pumpkin and set a jack stand on both ends of the axle tube for stability. You'll be fine.

Late replay, I know.
But your statement may very well be poor here.

The differential is a precision component, with extremely tight tolerances and is more difficult to rebuild than a Ford automatic transmission! Putting all the trucks weight on a very small area directly on the differential seems like a very bad idea. Many people do this and it's accepted practice for DIY mechanics. But I do believe you are flexing the steel by just a millimeter or two or three, and this definitely something you wish to avoid.

 

[and0r]

differentials with tube axles have their primary load placed 50% on each end where the tubes join with the diff.

placing a jack on the bottom of the differential is taking the entire weight of vehicles rear, and placing it on a very fine point directly on the flat bottom of the differential housing.

i dont think this is acceptable,
especially given the precise nature of the differential component

 

[drewactual]

that diff case is hardened steel... it could support two trucks and not whimper... if it ever encountered enough weight to impact it, it would snap/crack- not bend.

it's perfectly acceptable to jack a rear off the ground using the differential as a lift point. so long as the front is on the ground it won't even teeter.

 

[and0r]

Yeah that seems to be the consensus, but I really don't feel it is proper. Do you know exactly how much weight is being put on the Jacking point?

The tolerances for the differential seem razor sharp,
...a precision component

 

[drewactual]

put it this way:

it's thicker than an icebreaker ships hull... it's thicker and made similar to a engine block, which has several thousand fast burns/slow explosions, however you want to look at that, per minute... it's thicker and made of stronger material than the hydraulic lift arms used on a two or four post lift. if you shot the perimeter (case not face) with a .50BMG, you may crack the casing but nothing short of a 50BMG would do it... the casing doesn't warp and it doesn't flex... you could hit it with all your might with a sledge hammer while it's turning the axles, and it wouldn't phase it...... they are incredibly strong.

it's really not up for any kind of debate- that casing is stout and capable of being used as a lift point all day long with a full capacity load and full tank of fuel.

 

[Big Brian]

in one of my previous jobs,I worked at American Axle in the research lab. One of the tests I did was called "beaming" We would take a complete rear axle assembly and mount it in the dyno so that it was supported by the spring perches. Then a HUGE hydraulic ram was setup to push down on the top of the differential. It would cycle up and down for days trying to bend the axle until something broke.

The axles never bent, the spring perches and welds were always the first to go. We would weld new perches on and keep going until the test was finished

so jacking the vehicle up by the diff will not do diddly to it.

 

[stamp11127]

Wow fantastic job - paid to break stuff.....

 

[Bedrck47]

Wow fantastic job - paid to break stuff.....

Just think WE have members on this forum that DO NOT charge or get paid to break stuff
But they want FREE advice on how to fix what they broke

 

[Big Brian]

Wow fantastic job - paid to break stuff.....

lol I have stories...

For a period of time I ran driveshaft dynos. They are called rotary actuators. They would try breaking a driveshaft by bolting one end to a stationary plate and the other to the actuator. Twist back and forth thousands of times until something breaks.

Sounds like fun until you have 6 of them running and one after another keeps breaking the u joint before the driveshaft (then you have to put a new u joint on) and it keeps you running back and forth tending to the "crying babies" as I would call them.

And talk about noise!

glad I got away from that kind of work!

 

[and0r]

put it this way:

it's thicker than an icebreaker ships hull... it's thicker and made similar to a engine block, which has several thousand fast burns/slow explosions, however you want to look at that, per minute... it's thicker and made of stronger material than the hydraulic lift arms used on a two or four post lift. if you shot the perimeter (case not face) with a .50BMG, you may crack the casing but nothing short of a 50BMG would do it... the casing doesn't warp and it doesn't flex... you could hit it with all your might with a sledge hammer while it's turning the axles, and it wouldn't phase it...... they are incredibly strong.

it's really not up for any kind of debate- that casing is stout and capable of being used as a lift point all day long with a full capacity load and full tank of fuel.

no, steel is not made of diamonds.
and the only reason why its thick and hard is to prevent it from deforming, under an evenly distributed load, even by just a single millimeter.
the load of the differential and axle is spread evenly across the sides of the differential and across the ends of the axle.
really look at the jacking point when you jack the differential up. much force is being exerted onto a very fine point. im quite sure this is enough to deform the housing, even by just a single millimeter, either directly or by overall radius of the housing.

 

[and0r]

in one of my previous jobs,I worked at American Axle in the research lab. One of the tests I did was called "beaming" We would take a complete rear axle assembly and mount it in the dyno so that it was supported by the spring perches. Then a HUGE hydraulic ram was setup to push down on the top of the differential. It would cycle up and down for days trying to bend the axle until something broke.

The axles never bent, the spring perches and welds were always the first to go. We would weld new perches on and keep going until the test was finished

so jacking the vehicle up by the diff will not do diddly to it.

i commend your position at some kind of axle testing facility, however these supposed tests do not prove anything.
once again i need to repeat myself - the differential is a precision component. there is no way any of those "indestructible" differentials are going to last on the road more than 5,000 miles after running those tests. its quite silly of you to think these tests would even prove anything. yes, the housing wasn't completely destroyed, so what. this proves nothing. it seems that you are really going out of your way with poor facts and data. no offence

 

[Big Brian]

oh deary me

another expert

if you "theory" was true the highways and byways of this country would be strewn with vehicles with bent axles all over the side of the road

oh deary me