Archive >

Transporting a 300SE


The Problem

A 300SE with a non-functional air-suspension system can present some real challenges when trying to move the car. Even on a perfectly flat and smooth concrete surface, the car may sit so low that it can't be pushed or pulled without dragging something on the ground.

Under these conditions, trying to get the car onto a trailer without damaging the undercarriage is impossible. Something (or a lot of things) has to be done to increase the car's ground clearance.

There may be a number of reasons why a car may be sitting this low. A car that is in otherwise perfect condition, but has no pressure in the air-suspension system will sit with the lowest part of the car about an inch above the ground. But when the "rubber buffers" that limit the travel of the suspension are old and compressed, or even missing, the car can easily drop another one and half inches.

If the tires have had most of the tread worn off, then another half inch of ground clearance is lost. If the tires are of the more modern "low profile" design, then more ground clearance is lost.

When the rubber engine and transmission suspension pieces (motor mounts and transmission mount) has collapsed, the engine/transmission unit sits a full inch lower in the car than it should. Likewise, when the rear axle differential suspension pieces are collapsed, the differential is almost an inch below it's normal position. It's also very common for the rubber donuts that suspend the exhaust system to be broken, allowing the exhaust system to drop several inches, especially at the rear of the car.

The problem is how to get some of the lost ground clearance back, at least enough to get the car on and off a trailer, without damaging anything.

Possible Solutions

The simple fact is that the flatter the "approach angle" between the car and the trailer, the easier the car will be to get on the trailer. Anything that you can think of that helps to minimize the approach angle, the better.

A tactic that I use a lot is putting a large block of wood under the "landing gear" at the front of the trailer, and, with the trailer still connected to the truck, running the landing gear up as high as possible (not so high as to lift the rear tires of the truck off the ground though!).  This raises the front of the trailer and lowers the rear of the trailer. Placing 2x4 boards, laying on their side, under the end of the ramps also reduces the angle between the ramps and the trailer.  These two things are frequently sufficient to allow a car to be loaded without dragging anything.

Another possibility is moving the car to a slightly higher point, like a rise in the ground. With the trailer below the rise, the approach angle is almost flat. Perhaps you could dig trenches in the ground to back the trailer tires into. I have even resorted to letting most of the air out of the tires on the trailer to reduce the height.

Don't plan on getting the car up on a "roll-back" commercial tow truck. Assuming that you are not willing to cause any damage to the underside of the car, trying to get a car on a "roll-back", while not impossible, is probably going to turn out to be a more aggravating and time consuming exercise than you could anticipate. This is due to the simple fact that the "approach angle" to the bed of the truck is too steep for a car with no ground clearance.

If the car's tires will hold air, inflate them all the way up to the maximum permissible pressure. You aren't driving the car, so you don't have to worry about over-heating them. The more pressure in the tires, the higher the car will rise.

Consider rolling the car up onto long boards so that the car is a bit higher.

If none of these ideas provide enough clearance to load (and unload!) the car, then you have no choice but to get the car itself to sit higher. Getting under a car with no ground clearance is no small feat.

The first hope is that the jack "ports" in the car are not rusted out, and that the car (or you) has the original style jack. The original jack can be set to a very low height and it may be possible to get the jack inserted into one of the jack ports, even with the car sitting on the ground. Be careful, if the jack port is rusty, it won't support the weight of the car. In addition to the other problems, you will now have damaged rocker panel trim, and probably have a dented door or fender. (If a car is this rusty, you may want to reconsider buying it.)

Since 300SEs have "anti-roll" (sway) bars on both the front and rear suspensions, lifting one corner of the car off the ground may not make it any easier to get to anything that would provide extra ground clearance. For example, if you are jacking up the left front corner of the car, but the right front corner's suspension is still fully collapsed, the sway bar is going to hold the left front wheel in it's original position. It won't drop down until either the sway bar is disconnected, or, the right front corner of the car is also jacked up. Since you need to get to both sides anyway, jacking up both corners of the car is the preferred approach.

If the car's jack ports are rusty, then using the car's jack to raise the car is not an option. The next best approach is a floor jack put under the front sub-frame. If the car is not on a hard surface, i.e. concrete or asphalt, it may be possible to dig out under the sub-frame to make room for the jack. MAKE SURE to put some type of padding between the jack and the sub-frame, especially if you are putting the jack under the center of the sub-frame.  If you don't, you WILL dent the bottom of the sub-frame.

A better choice is to locate the floor jack under the large hinge pin that connects the inner end of the lower A-arm to the sub-frame. These hinge pins are quite substantial and will put up with a lot of abuse.

Now that the front end of the car is up in the air, you need to do something to keep it there. You probably don't have any, but putting much larger wheels on the car will help. A more common approach is to put something (blocks of wood) between the lower A-arm and the sub-frame. This is where the factory rubber buffers are installed. The wood can be placed between the rubber buffers and sub-frame. This may get you an inch, or so, of additional ground clearance. If you are industrious, remove the five small bolts that hold the air-suspension piston to the lower A-arm. This will allow the piston to move out of the way, and larger pieces of wood can be placed between the A-arm and the sub-frame.

If you are really industrious, have some "inflating" linesInflation Lines.jpg (42290 bytes) made and be prepared to replace a (or, several) defective air-bag(s). These "inflating" (for lack of a better name) lines screw into the air-bag's steel chamber in place of the air supply line of the air-suspension system. Once done, a standard air compressor can be used to raise the car.

Depending on how low the car is sitting, getting the rear of the car raised can be a lot more unpleasant. The same issue applies here in that jacking up only one side of the car doesn't allow the wheel to drop down from the car. Both sides need to be raised.

If the rear jack port(s) are rusty, then the next best approach is to try to raise the car with a floor jack. This can be done relatively safely by placing a 2x4 board about 12 inches long, on it's edge, up against the frame rail behind the rear wheel, between the fuel tank and the trunk well. The 2x4 provides just enough height to keep the jack from touching anything else on the car.

If both rear jack ports are rusty, you may need two floor jacks and two 2x4s.

Once the rear of the car is up in the air, again, you need to find a way to keep it there. The typical approach is to place blocks of wood between the top of the axle tubes and the floor of the trunk. If you can remove the air-suspension's steel air chambers, bags, and pistons, and the "travel-limiting" rubber buffers, then short pieces of 4x4 can easily be placed between the axle tubes and the trunk floor. This will really lift the rear of the car, even higher than it's normal height.

An approach that doesn't require removal of the suspension components is to use thinner pieces of wood placed in the same location. You won't get near the extra ground clearance, but it's much more straight forward than the other approach. With either approach, remove the wheels from the car to make it easier to get the blocks of wood installed. With some patience and luck, wood blocks can be placed properly without removing the wheels, but it's much easier with the wheels removed. Also, remember that the car is going to be bouncing around a lot when being transported, so it's important to get the wood blocks placed so that they won't fall out.

Again, if you are the industrious type, install the "inflating" line and be prepared to replace defective air bags. The rear air chambers are connected together by a common air line. The system's supply line enters only the left-rear chamber, so only one inflating line is required.

If you are planning to install the inflating lines, and possibly new air-bags, make sure there is a good source of compressed air. The rear of the car will come up with less than 100 psi, but the front will require 125-130 psi.

Assuming that you are transporting a car with an air-suspension system that works, you still need to watch out for a few things.

The air-suspension system is an "active" suspension. If the system thinks that the car's level is too high, it will bleed air out to reduce the height of the car. If the system thinks that the car's level is too low, it will allow more air into the system to raise the car's level. This works fine as long as the system has a supply of compressed air. However, unless you leave the car's engine running while transporting the car (not a good idea), the system will eventually loose all of it's compressed air supply. If the system continues to bleed off air (because of bumping around, or an air leak), the level of the car will drop to the point where the car is sitting flat on the trailer. Unless you keep an eye on them, the chains or straps holding the car on the trailer will get loose and the car will really start bouncing around, possibly damaging the car, or even letting the chains/straps come off (!).

On all 300SE finback sedans, and all coupes and convertibles built up to August 1965, there is a "pull-knob" under the dashboard that controls the main air valve of the air-suspension system. The normal position is with the knob pushed all the way in. When pulled out (the "lock" position), no air is allowed out of the system specifically to keep the system from bleeding air off and therefore maintaining the height of the car. On coupes and convertibles built after August 1965, the knob has three positions. The middle position is the "lock" position. The problem is that, after all these years, the valve that controls the lock generally doesn't work very well, so don't depend on it.

My tactic is to let all of the air out of the system and strap the car down to the trailer in this condition. This forces the car and the trailer to move as a "unit" and keeps the chains/straps from getting loose due to suspension collapse. The air can be bled out by loosening the air supply lines at the air chambers. When the car makes it to it's destination, tighten up the air line connections and remove the chains/straps. Start the car's engine to pump the suspension up.

Assuming that you haven't said "forget it" and sent me an email offering me the car for a really good price, make a plan as to how to best approach the loading/unloading and transportation problem. The type of trailer you plan to use, the ramps, the car's current location, and it's final location will all dictate what the best approach is. If you haven't seen the car yet, then planning for the "pick-up" is tough. Ask the person at the car's location all you can: Is the car sitting on concrete, asphalt, gravel, dirt, etc. Are there any small rises in the ground? Can you get a trailer all the way to the car, or will the car need to be pulled to a new location before the trailer can get to it. Is there a supply of compressed air available? Is there electricity available?

When I go after a car, I take a whole truckfull of equipment with me. At a minimum, I take a "come-along" (a small hand operated winch), several different sizes of wood blocks, and at least six 2.5" wide, 30 feet long locking straps, and a full set of hand tools.

If I'm not sure exactly what I might get into, I also take 100 feet of air hose, a long extension cord and drop-light, fully inflated wheels and tires for the car, lug wrench and a long steel bar for digging and prying, a shovel, two car jacks, a small floor jack, two 8 foot 2x8 boards, and a spare tire for the trailer.

As with anything, hope for the best and plan for the worst.


[0] Message Index

Go to full version