Hot Rods Using a floor jack to lift a car placed under the 9" ( center Pumpkin

This was brought up just briefly recently and got lost in the shuffle since it was under a different heading. This is something I have done a long time and never thought twice about it. The subject - One should never jack a car up putting the jack under the center section/pumpkin on 9 Inch Ford Differential, then lift the weight of the rear of the car, that it can distort or tweak the diff.

The answers ran 50/50 but no concrete answers to satisfy me ?? Gene

 

http://www.floorjackadvisor.com/blog/can-i-use-the-differential-as-a-jack-point/

 

Done it for 45 years, no reason to stop now. Never damaged a housing. Raced for 25 years and we ALWAYS jacked up the car with the center section, no problems changing gears on a 9" after doing it thousands of times. Some people worry about everything.
SPark

 

X2

 

You wouldn't want to scratch the paint on it.

 

If the pumkin is not installed maybe a slight chance of warping but very slim. If it is bent the ring and pinion unit should be hard to install, A round round track trick was to place a 1 inch socket on your floor jack and then raise car.on the center of axle housing The right tire should have come up first . this was called checking wedge. This should have bent something..In the morning I will check my stash and see.

 

Been doing it that way for over 50 years and never bent a housing yet. Just lucky, I guess.

 

If they bent that easy they'd bend driving down the road.

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I have done it for years but as soon as I jacked up the car I made sure to put jack stands under each side of the rear end then let the jack down till the weight rested on the jack stands. Bruce.

 

There probably are very few rearends in existence that haven't been lifted at the pumpkin at least once. More so on the (old) ones we seek at junk yards. IF they bent that easy, they'd still be in the junk yards...

 

Hey BD,
That hydraulic floor jack was the best thing ever! It made working on any car so much easier than a wobbly bumper jack. Even with the use of jack stands afterwards, the bumper jack was an emergency item only. It was not made for daily use on bumpers, as a matter of fact, either were the bumper connections to the frame.


We were lucky that a friend of my dad, in Los Angeles, had several Walker Hydraulic Floor Jacks available and gave one to him. That early Walker version in 1959-60 was a life saver. It made changing the 4:56 rear end gear housing easier and less work. It also made access to the car easier after installing the jack stands. For the whole time we owned it, it never leaked or faltered. The rear end never had a problem. Those late night crawl under the 58 Impala to change over to the 4:56 for the weekend drags at Lions were much more pleasant with the use of the hydraulic jack helping out.

Jnaki
Any suspension system/ rear end, shafts, springs, etc has to be heavy duty, even the stock ones from the factory. If the build has poor quality, home made installations, then it could be suspect. But, any solid rear end from the factory that most hot rodders use, will withstand lifting in that hydraulic jack. If you are worried about the hydraulic jack damaging the center housing, what about leaving the jack stands on the axle housing? They are strong enough to withstand lifting with the hydraulic jack...

From 1959 to the time I sold it to a friend in 1975, it was a flawless piece of garage/hot rod equipment. I wish I had one that was light weight enough to carry around in my 40 Ford Sedan Delivery (s) back then.

 

The late model Ford rangers are not supposed to be lifted by the pumpkin but i could never see it being a problem if the bed was empty. The back can't be that heavy.

 

On a normal car or truck with a sound rear end - 99.9 percent of rear ends can handle it without issues.

Jack up a car with a severely rusted rear end, an over loaded vehicle, a loaded dump truck, a heavy work van and there is a good chance it will bend.

 

Actually had this argument at work, but not because of the rear bending. Guy comes into my shop with a newer Shelby Mustang- "that" type with the hat and jacket. The car was lowered so in order to put it on the lift I had to jack the car up from the rear to get the arms under which is common practice. He says to me " Oh, I don't like that, it says in the owner's manual not to lift the car like that..". I explain to him that they say that in the maunal because they don't want you on the side of the road changing a tire with the car balanced on the rear. He throws a fit, like a typical mustang owner, and gets my boss. He wants me to do it his way, drive the car on wood planks. I tell him no, so he gets the lubie kid to do it. Sure enough, the car chucks the 2x4's out the door, and almost drives though my toolbox. But what the hell do I know? I only do this shit for a living! Since then, I always avoid the Shelby's, Roush's, Saleens, or any other car with stripes for that matter.

 

Like many who have replied,I too have jack up cars using the same procedure for 50 plus years and never had any problems doing so.

It's works for me and I see no need to change the way I have raised the cars in the past. HRP

 

What would bend? I have cars in the shop that start at 5000 lbs. Some are more from time to time. There was 1 car that showed a bit of change picking it up from the axle, a 31 Ruxton. To be fair the whole car was a bit sub-standard as it was rushed to market from a guy who's normal M.O. was corporate takeovers. Beyond that, never an issue like everyone else has said.

 

Haha I miss the days when "It's fine, go for it" was sufficient. Everything gets questioned now- it's a miracle anybody does anything!

 

Driving down the road, the loads and supports are close together. Wheel bearings to spring mount distance. The center of the housing doesn't see much load.


On a centered jack there is more distance between the load and support, with a greater bending moment. Like breaking a stick across your knee.

If that's enough leverage to create a permanent deformation depends on the particular housing and the weight of the vehicle.

 

Agree. Always better to jack closer to the axle ends rather than in the center.

 

I don't think I've ever jacked up the rear any other way. And I have jacked up a lot in my 71 years.

 

I was being sarcastic. Your point is valid, but I still don't think it hurts anything to jack underneath the pumpkin.

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Zactly
These housings in particular that have the small radius and welded tubes. I'd be more inclined to trust the aftermarket versions but there have been a few of them reported to have sketchy welds where the tubes enter the housing.
On top of that, not knowing what kind of life OEM rearends have led as 31Vicky stated.
I know, it's how we've done it forever, but in a perfect storm scenario.............
May never be a problem in a light hot rod, but you see these in any configuration of cars.

 

Morning,

Stick a rear end narrowing jig, bar, bushed up third member, and housing end bushings through a stock 9". Might be surprised how NOT straight some of these are and the car has been driving down the road for years with no problem. Don't sweat it! Not saying it's impossible but you'd be hard pressed to bend your housing with a floor jack.

 

Simply bull $hit. Wont' hurt it unless you might have 10 tons in the trunk..my2¢

 

It has been standard practice, since the hydraulic jack was invented.

If it were a problem, it would have been revealed by now.

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Wow, better not run a pinion snubber on it and do any 6,000 rpm stick shift launches with it, like an 8.75 mopar.

 

I too have lifted many vehicles this way. I've never seen a hint of a problem. While the diagrams Relic Stew posted do show a considerable difference in load and leverage between what you would find in lifting and normal operation, you also have to consider that the normal shock and loading that would come from driving would never be experienced while lifting at the center. Under normal circumstances I don't see a problem. There may well be some rear axle housings out there that will not do well being lifted this way, but I've never yet come across one.

 

sounds more like a Corvette owner

 

Some Ford 9" housings will bend; I've personally experienced it...

In the early '70s I had Art Morrison slightly narrow (about 4" IIRC) a 9" housing for me on a OT '70 Montego (this was when he was still working out of his barn in Milton). I was also doing some suspension upgrades at the same time, bigger sway bars and lowering it. He narrowed/straightened the housing, I reinstalled it. I also added a Addco rear sway bar. This bar attached to the housing, with the end links going up to the frame rails. This was a 'small end' housing, so the axle tubes necked down in size at the leaf spring end. Because of the taper, I couldn't get the bar mounts out towards the ends of the tubes as far as I wanted. I was assured by Addco this would be fine....

At about 5K miles, I had a axle bearing failure. Ok, I replace the bearing. Another few K miles, I lose the other side. Now I'm wondering a bit, but go ahead and replace the bearing. I go through another couple of sets of bearings at about 5k miles or less each, there's definitely something wrong. Pull the housing, take it back to Morrison. He pronounces it definitely bent, can't understand how he screwed it up and straightens it for free. Reinstall it...

5K miles, another bearing failure, with the other following shortly. Pull the housing yet again (and anybody who thinks this is easy...) and take it back to Morrison. Yep, it's bent again. Morrison says it's not his fault, it left there straight, and I have to agree. So after much discussion, we figure it has to be the rear sway bar. Pulling the bar off should cure it. He straightens the housing again (not free this time, LOL), reinstall minus the rear bar, no more bearing failures.

So I do some research, looking for a different type rear bar. I discover that Ford factory bars on the leaf-spring cars are always chassis-mount, with the end links going down near the axle ends near the spring pads. And not all 9" housings are the same.



This is the 'light' version. This type is what I had, and these will bend...

This is the heavy version; considerably stronger, although under extreme use even these need to be braced. This is the housing Ford used on the later rear coil cars with axle-mounted sway bars. This type was also found under late full-size and all late big-block cars.

One thing I learned is if you need a puller to get the axle out and have to work at it, the housing is probably bent. If you need to beat the axle in, it's definitely bent..... Very light beating, it's probably ok. Heavy beating, probably not... If the housing is dead-nuts straight, you should be able to pull/install the axles by hand.

 

No one has mentioned the loading of the rear end when the car hits a chuck hole. I watched cars and trucks going down a rough road and watched the rear end jumping up and down so fast it becomes a blur. That 75-80 pounds exteneded on an 18 inch tube for leverage. Always amazed me they didn’t bend then. If the housing can take that, don think a unloaded car/truck/ Jack would bend one. Bones