The Stovebolt Site Forums The Shop Area General Truck Talk Proper LIFT points on an AD truck on an assymetric lift?

Sometimes our AD trucks need to be raised on a hydraulic lift to do work on them.

I am blessed with having a commercial Rotary 7500 lb hydraulic lift in my outbuilding.

This is the professional "asymmetric" style, which allows the vehicle to be positioned rearward a bit, so that the driver door can be opened without hitting the driver's side lift column. The lift handles this for to rear "asymmetry" by having 2 short adjustable arms that go under the front of the vehicle, and two longer adjustable arms that go under the rear.

Usually, you are suppsoed to try to place the front arm "pads" under the frame rails as far forward as you can. On an AD truck, that would mean basically just behind the rear mount points for the front springs. (You can't go further forward because the springs block access to the frame rails, obviosuly).

But on my 55 AD truck with its custom dual exhaust pipes, the pipes actually block off access to the front frame rails in that area. I need to place the pads a bit further aft on the frame rails I guess, probably aligned with the front edge of the cab doors.

I have calculated that the center of gravity of the truck is almost exactly under the middle of the door:

According to the factory manual data, the weight disribution of my specific AD truck is 57% front axle, 43% rear axle. The wheelbase is of course 116 inches. That means the center of gravity is .43 x 116 inches = 50 inches back from the front AXLE. That places the c of g right under the center of the door.

So I am not super comfortable with that little distance from the pads to the cneter of gravity (if I could get them right near the rear mounts of the springs, they would be several inches more forward).

Have any of you who work in automotive shops, or that have your own lift, run into something like this?

How have you addressed it?

Or, am I worried too much - as long as the pads are somewhat forward of the c of g, and I don't exert huge downward forces on the front of the chassis, am I ok?

Jim G

Well, I'm not knowledgeable, and I'm 13, but if nothing else you could always take part of the exhaust of to put it on the lift.

How tight is the exhaust to the lift point? You should be able to flip the pad up to the verticle position, then locat it so that the frame rail is between the 2 ears on the pad. That will gain you more clearance.

Or you could throw a hundred pounds of sacked something in the bed against the tailgate. 80# bags of sand are cheap.

or place the ft hoist arms on the rear of the front leaf springs...

You guys have given me some good ideas.

The "ballast" in the cargo bay is an especially easy one. Good thinking.

Putting the lift pads onto the rear of the front springs will also work in MOST cases. The exception is when I need to take those springs OFF, as I WILL be doing to replace them with mono composite springs. Once I do the mono composite thing, I'll need to desist from using the springs as lift points, because while STEEL leaf springs can handle that kind of unanticipated loading point, I am not sure about COMPOSITE springs doing so. I don't want to take a chance.

I am also going to try to put the lift pads in their vertical position and thread past the exhaust to the frame rails, but it might be hard to do so - the exhaust is pretty close to the frame rails on each side.

The exhaust routing problem will disappear once I chnage the engine over to the V8 I am planning to do. I will ENSURE I run the dual V8 exhaust pipes AWAY from the frame rails, more towards the centerline of the chassis.

In the meantime, the ballast idea sounds liek a great safety idea to give me peace of mind. It is especially workable since I store 4 or 5 donkey feed bags 6 feet from the rear of the lift area, and those bags are 50 pounds each. Because the leverage of thsoe bags by the tailgate area of the bed would be so great compared to the leverage of the front mounted engine weight - at least 8 feet of leverage for the bags to the c of g, versus 2 feet for the engine, I'lla ctually have to make sure I don't put too MANY bags back there!

jdl: Thanks for the suggestion on temporarily removing the exhaust segements, but the exhaust system is WELDED together.

Jim G

Jim G ,
We have the same lift in my brothers shop ,For added PEACE OF MIND try this , after you have the ballast , we have used Ratchet tye downs around the lift arms and frame an sinched it down tight on IFFY ONES...at LEAST ...if she would start to tip ..it would hold till YOU got out from under it an got her back on the ground.
Tim
P.S. not the HARBOR FREIGHT ONES ...a good set of 2" wide ones.

Hi Jim

I've owned a few Rotary hoists over the years. I had what they called truck adapters. To use them you had to stand up the pad and the truck adapter would slide over the pad. It was about 6" taller and you could probably turn it sideways to clear your exhaust and still make good contact with the frame rail. I have also moved the vehicle forward or back some to get a better position to contact the lifting points. I would always put vehicle up so the tires where about 6" off the ground and go to the bumper and give it a few good shakes up and down to make sure its going to sit ok, if its going to move better at 6" than 6'.
be safe, Don

We have those same adapters. I have a concern that they may not clear the exhaust just from the description of how it's routed.

Thanks for the pro inputs guys.Keep em coming. I want to do this properly and safely.

Jim G

I rack vehicles all day, as a part of my job. I try to rack them as best I can for weight, considering lifting points. Then once a few inches off the ground I shake them real good. Never had one fall off yet. Had the feet on the rack slip down while I was under it, which can be exciting, but never had one fall. Being retained by 3 legs will at least allow it to be set on the ground to be re-situated. Back to the question at hand, you'll lilely be fine picking it up as far forward as you can. Think of it this way: Most modern cars have the majority of the weight on the front, yet can't be picked up until behind the front wheels.

Devin

Thanks, Devin!

Jim G