Hydraulics on a Slightly...Custom Project

[firebirdta84]

Hey everyone,

I hope I am not imposing, but in my search for hydraulics experts, this forum popped up first on my results. If this thread is not fit for this board, please let me know.

I own one of the very few surviving Trans Ams from the 1980's television series "Knight Rider". A true childhood dream come true. I am working to restore the car to its as-used appearance on TV.

What makes this car interesting is that the factory suspension has been augmented with some hydraulic cylinders designed to raise and lower the car.
After much research, it was determined that this car was outfitted with these hydraulic cylinders for a specific episode where K.I.T.T. can lift his body to clear some terrain. Here are the screencaps showing the car before and after the suspension lift:



Unfortunately, in the years since the show has been on the air, most of the hydraulic setup was removed. Presently, only the front hydraulic rams are still in place:





These cylinders are welded to the car痴 unibody and, when activated, push on the lower control arms to elevate the car.
The rear cylinders are gone, but the holes where they were mounted are still there, along with some of the welds. The hydraulic pump and all hoses are gone.

My goal is to re-create the rest of this setup using parts identical to the original 1980痴 era ones. Unfortunately, there痴 no markings on the two hydraulic cylinders, so I cannot find a manufacturer in order to find two more for the back.
There is a brief scene in one of the episodes where I can make out the very top of the hydraulics in the trunk area (see below). Looks like the pump is in the trunk and the line comes off it and splits into two.



I am NOT familiar with hydraulics, so I am looking for some experts who can help me with the following:
Determining the amount of pressure needed to raise the vehicle
Finding the correct pump and hoses that can handle the pressure
Finding the correct sized hydraulic cylinders based on the ones I still have

Thanks!
Joe

 

[teg]

Sounds pretty cool... I assume the hydraulic cylinders are single acting? (only a single nipple at the top?) Sounds like you might be able to use a dump trailer hydraulic set up like the one below...

http://www.northerntool.com/shop/tools/product_200642008_200642008

 

[oldnslo]

Back in the 80's & early 90's there were several companies selling kits for making cars into low riders or for bouncing or hopping them. Majority of them that I know of were based in California. Not sure how many are left today but you might want to try some searches for low riders, car hopping or jumping. If I remember correctly Red's low riders was one of these companies.

 

[IceStationZebra]

I'm guessing that the cylinders are shot because the port is open to atmosphere, which lets dirt in, and they are running without oil. At a minimum you will need new seals, but the bores are probably scored and unusable. ISZ

 

[BHD]

lowrider hydraulics search
lowrider hydraulics - Google Search

 

[LD1]

Way too many variables and way to indepth of a project to be of much help without a ton of other information on your part.

Want to know what pressure it takes to raise the car......that isnt the question to ask. You need to know how much force is required. Then select a cylinder size....THEN can you arrive at a pressure requirement.

If you have a 1.5" cylinder running at 3000psi....thats 5,300 pounds of push PER cylinder.
Increase the bore of the cylinder to 2" and you only leed 1600psi out of your hydraulics to generate the SAME amount of force to lift the car. (or if you still use 3000 PSI you can generate about 9500 pound of force.

So the question of how much force is needed.....

Another tough one to answer because I dont know the geomerty of where/how the cylinder is mounted. Pushing on the lower control arm like that...at some point you begin fighting the springs...but you also have to account for leverage. The lower control arm is connected to the tire that makes contact with the ground....the other end attached to the car. If the cylinder were placed right in the middle of these two points.....your cylinders force divided by 2 would be about what it would lift. SO what does that corner of the car weigh?

As far as the hydraulics and hoses and all that....a simple 12v pump unit like would be found on a dump trailer or a dump bed insert would be perfect. As would 1/4" hoses and appropriate fittings. But you really need to figure out the cylinder sizing first.

If the cylinder is mounted somewhere else on that control arm....do the math. Its a simple lever.

What length stroke do you need? Want to make sure you get ample lift, but dont want too long of a cylinder that you try to over extend the lower control arm and bend it....or destroy the mount to the unibody with a cylinder with too much force.

 

[firebirdta84]

Thank you for the great info, LD1 and all.

To give you a bit more info. The cylinders on the front are 1.5". They welded a plate to the TOP of the front springs, so when the cylinder is activated, it pushes not on the control arm, but on the top of the springs, which in turn push on the control arm. I don't know the stroke as of yet, but judging by the scene in the episode where we see the car lift, it's only 2-3 inches in the front and 5-6 inches in the back.

The entire car itself weights only 3300 lbs, with most of the weight (obviously) up front, but I'd guess that each corner weighs no more than 1000 lbs.

I'm going to source a 12V pump and hook it up to the front cylinders to start, just to see if I can get lift.

 

[flyerdan]

I don't quite understand how this was set up to alter the top of the spring; they generally have to be secured pretty good to the vehicle in a formed pocket. Granted, this was a special purpose built vehicle where drive-ability, safety and reliability wasn't even a consideration. Before investing a whole lot of time and money, put an air hose to it and give that a try. Most air shocks will lift quite a bit on 75-100 psi and a hydraulic cylinder will work well enough on air for a test. They might have bodged it up to the point that it's scary to just stand next to it when extended, much less drive it.

 

[N2DFire]

I know I'm kind of coming late to the party, so to speak, and I hate to muddy the waters even further but are you 100% sure these are hydraulic and not pneumatic?

Also - here's a link to a generic install of a hydraulic kit that shows the over spring mounting you describe. Not knocking our experts here but maybe a forum dedicated to Auto / Low Riders might be more helpful.

Complete F-B-S-S Hydraulic Install in a Car | Eternal Rollerz C.C.- International Traditional Lowrider Car Club

Best of luck either way - looks like a pretty cool project.

 

[firebirdta84]

I pulled off the fitting from one of the cylinders, and it's filled to the top with hydraulic oil. I had originally thought they were pneumatic until I saw that.

Thanks for the link to a setup similar to this one!

I should note that this car is NEVER driven on the road, and is only trailered to and from events, so the safety/reliability of this system is not of too much concern to me in that respect. Thanks!