I know they say there is no such thing as a stupid question but this one feels like it. I have put a jack under a lot of cars and trucks over my years and some with straight axels. Most though had parallel front leaf spring. So is it all right to jack the front of my 39 sedan up by placing the floor jack under the center of the straight axel, or should I do it one side at a time? I need to get it up on stands to start the brake work. Thanks
I "felt logically" like it was better to jack on either side , but have nothing to go on one way or other. Funny you post this as I was going to ask the same question basically about jacking on the center "pumpkin" on the rear axle. I've done it that way for years with no problems , but due to some recent threads on here about tubes coming loose from center , I wondered if jacking that way would cause same problem in a GM style or problems and warping the housing in a one piece housing. Two different but similar situations
I am going to take the high road here and not make any wise assed comments on how to jack. You are welcome
They have been jacking them up in the center of the axle for 100 years. I never heard of it loosening anything. Jacking up one corner at a time will put a lot more stress on the suspension, frame and body.
I had an off-topic late model Mustang that had an 8.8 solid axle in the back and some of those late model lemmings on one off the Mustang boards became convinced that you couldn't lift it on the rear center as it would bend the axle. Nothing would convince then that they were full of it.. too bad common sense is a major requirement of owning a a computer, much less a car.
Except the force is being transferred to the ends of the tubes where the u bolts are, acts like a pretty big lever to lift the vehicle. If you jack under the u bolts I would sure hope you don't damage or overload the suspension!! Sent from my iPhone using The H.A.M.B. mobile app
They get that from the owners manual, says it right in there. I've not seen any car or light truck ever have a problem jacking it up on the differential. On an over loaded pic up or van is another story
I've also seen a few factory manuals that say don't jack a rear end from the center. I still do it...
If it cannot handle the jack, it certainly cannot handle the road. As for the front axle, jack away. You will do it no harm. This is River Rouge steel, what your front axle is made of, twisted seven times, without a fracture.
I've been doing it that way since I moved up to a floor jack in the late '70's , but the thread where the welds let go got me to wondering......
Stop and think about it, if a rear was that easy to bend, wouldn't it bend when one side or the other hit a pothole or a big bump? Sure, there have been cases of welds breaking or axle tubes coming out, but I'd bet there was already a bad weld or fitment issue beforehand that went unnoticed. We jack up loaded semi trucks by the center of the axle all the time. If there was a problem with it, it's sure show up doing it then.
The loading on the housing is quite different when the car's weight is supported by the wheels, vs when it is supported by the bottom of the center of the housing. But most of us here don't even know what a free body diagram is, let alone how to draw one.
The first mod to a 8.8 is to weld the tubes solid to the chunk is it not? Vs Depending on the plug welds or pins to let it do that^^^ Here's what it looks like when the pins shear
All I know is that while my shoulder was immobilized this year after surgery I had to jack with the other hand. I have been jacking cars under the center of the axle or any sturdy part on the center of the chassis for well over40 years ( if you don't count my fooling around in the old mans shop when I was a little kid), that old axle will lift the car just fine.
I have always jacked from the center. But I have to jack my front from the sides because its so low that I can't get a jack under the center of the I beam. So I have to jack to raise up the sides, then take the jackoff and re-jack the center.
A semi is a different animal and you'll most likely never have a problem with a car or empt truck. When you hit a pot hole or just going down the road the road shock is focused between the wheel and the spring mount & 1/2 on each side. Get a pick up loaded down full with gravel and a flat tire jacked up in the center and you can snap shit. Or a work van loaded with 4000 lbs of shit same thing.
I notice all the problems with rear axles falling apart seem to be Fords. I can't address this as I seldom work on Fords. Have never had a problem with Chrysler products.
Sure, but rigs like the one that I showed put upwards of 10k lb-ft of torque to the axle. It takes about a half-hour to properly execute the procedure, in any case.
Yep, did that many times, but truck axle housing are usually solid castings or forgings, not 3 pieces welded together. Still, I've never hesitated to lift a car from the center of a rear axle housing.
Trust me I get it. This internet version of the sky is falling stuff started when it was found in owners and factory service manuals - Do not lift by center point load on differential. I guess the point I was making is that although the 8.8 is a very durable unit even in stock form, you'd better know to weld the tubes before pushing it. Sticky tires and a hard launchs from a stout power plant, or pulling too way too much weight will eventually cause issues with the pins too.
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