Vehicle Hydraulic Lift

Most ride control systems available on cars/trucks/motor homes today are not hydraulic, they are air powered. If you search for 'airbag suspension' you'll find tons of information. Basically it's a bladder which is installed between the axel and body so when inflated or deflated the ride high changes. If you're looking to alter the ride height of a vehicle for on the fly adjustability I would stay away from hydraulics and go with air. It not only is much more inexpensive it's much less complicated as well. Citroen in the 60's-70's has fundamentally had a hydraulic suspension on some of its vehicles, which they pioneered the use of. (http://www.actwin.com/toaph/citroen/work/work.htm l ) Today versions of that hydraulic system are used on the Mercedes 600SLC and RR Silver Shadow – primarily as an anti-roll device. What is the overall goal your trying to achieve here?

Yes, this system is used on a vehicle... F1 and some LeMans vehicles employ a system that raises the vehicle to allow for faster pit stops and this also begs the question... what do you really consider a "suitable" working height? Off the ground enought to get under the carriage? In that case consider a multi-sectional telescoping arrangement. This will require a large reservoir of fluid and a suitable pump.

I was under the impression that these systems were pneumatic, and only allowed the vehicle to be lifted a couple of inches. I'm of the firm opinion that a vehicle-borne raising mechanism would be considered far too dangerous by manufacturers (and anyone with an imagination) as it would be way too susceptible to failure through misuse, lack of servicing, unsuitable grounding, etc. Remember, if there's the slightest possibility that someone, somewhere could do something stupid to injure themselves, chances are............they will!!!

Many large Class A RVs (Motor homes) have hyd. levelers installed. We had a 1984 Pace Arrow 34' RV with hydraulic leveler with lift cylinders at each axle corner. Control panel is located on floor at left rear corner of drivers seat by entry door accessable even when standing outside the vehicle. Shop used it to lift front tires clear off the ground to rebuild "A" arms and brakes. As this was a leveler system, there was no safety mechanism built in for under vehicle maintenance so safety jacks were necessary. Also, must be careful to lift vehicle evenly as windshields were popping out of place at lower outside corners. Suspected uneven lifting may have twisted body enough to "work" the large glass panels out of place. (Had to pay a glass company to reseat/reseal panels in place!) Check for wrecked RVs, you might be able to get an entire system cheap. but beware, these are sizeable units (bus size), but at least you'd get the concept....

If you are looking to raise something like the back of a pickup bed for use as an elevated working platform, you might consider the airport. I recall seeing the cleaning crew pull up to a plane with what looked like a moving van. The box on the van then elevated (hydraulicly) to the height of the plane. The crew then walked right into the plane and began working. If I remember correctly the lift looked like some kind of scissor lift.

Regarding the safety issues of using hydraulics or pheumatics as a method of lifting a vehicle, a previous reply discussed the obvious dangers. Using air bags, such as seen on big-rig suspensions can be combined in series to get considerable stroke, but are subject to catastrophic failure causing a sudden collapse. The same is true with hydraulic or pneumatic rams except a catastrophic failure would be isolated to the flexible pressure hose. I saw in an engineering magazine some years ago a device that mounted on a ram with the rod passing through it. This device would expand when pressurized air or fluid was present allowing the ram to collapse. If pressure was lost the device would clamp around the rod and prevent any movement. Pretty cool.

Try looking at fire trucks, portable cranes, backhoes, etc. anything that requires the vehicle to be level while in operation.

Unclear! Are you wanting to lift the vehicle to do maintenance or alter driving (ride) operations? In either case many light aircraft OEM's use a hyd. power pack to operate the landing gear. The power packs include a reservoir and reverseable motor. Compact installation and good performance.

Formula 1 race cars use a pneumatic lift system to raise the car up to change tires while in the pit. The air source is external to the vehicle, and is plugged in in the pit. There are various "funny cars" for show that use pneumatics and hydraulics to make the vehicle jump and dance. Don't think I have ever seen one that raised itself up to be worked on... Many industrial vehicles have on-board hydraulic systems for doing various tasks, but I have never seen one that raised itself. Should be easy to do, though. Cylinders at each corner, tied to an engine driven pump through a manual control valve.

I remember my mother telling about a car she has around the early to mid 60's called a citreon or citroen. It was a foreign car, I believe French. She told me of how she got slid under a semi truck because of the ice. She said she feared telling my father, but when she called him he told her to drop the hydraulic system and see if you she could get out of the pickle. AND it worked. She told me the design was made for just such instances. Anways, I hope that helps a little.