Here are some examples of rust.

So click away

passenger cowl


rusty pan 

bottom

driver

inner fender

inner

fender well

inner fender

AC box

rusty nose

suspension

pan

suspension

pan

battery box

tank

support 

front pan

gas tank

support

lateral

tank

support

lateral

tank

support

cowl

Rust Inspection On a Porsche 911

Jamie Novak and Dave Winters
novak@bloch.nrl.navy.mil, dtwinters@mindspring.com

PREFACE: The Pre-1976 Porsche 911 chassis was not completely galvanized. It is therefore important to inspect carefully for rust. This is meant to be a stepwise guide for inspection of a 911 chassis prior to purchase. This is by no means comprehensive but rather a guide for the consumer to do a preliminary inspection. If the buyer is uncertain of the car an inspection by a qualified mechanic or body shop is highly recommended. 

There are many buyers that are familiar with the SC, Carrera and other newer models of the 911. Many times these buyers have driven an early car and fell in love with the lightweight chassis, high revving engines, and sound of MFI or Carbs in full song. The early cars have a sound, smell and spirit that is, in my opinion, completely different than the later model years. The buyer is hooked and wants an early car. 

The first step is to find a suitable car. Let's pretend you have just found your dreamcar for sale. Its the right color and year. You make the call and ask some questions. Everything seems in order and you set up an appointment to inspect the car. What you do next depends on your familiarity with the Marque. There are many inspection guides that help the buyer decided on mechanical and cosmetic conditions. The purpose of this document is to show the buyer how to look for the more common areas that rust on the early 911s. I will cover the common areas to the early 911 and then list specifics for a targa and coupe. 

There are a few things that need to be done in preparation to look at the car. I suggest bringing a few tools to help with the body inspection process. First, plan to get dirty. You will be reaching into wheel wells, under engines and crawling on the ground to look at the car. You do not want to be doing this in your nice clothes. The tool list is rather short. The most useful to me are a flashlight, flathead screwdriver covered in tape and a magnet. A philips and flat screwdriver as well as a minimal set of wrenches is good to have with you. The flashlight will help illuminate areas under fenders and wheel wells. The magnet will help find areas that are filled with bondo. The screwdriver will help you poke for rust. The tape helps protect the paint from scratches. I also bring a clean rag. Old clean t-shirts strips are nice since they are soft. They are useful for many things including cleaning hands after the inspection. It is a good idea to also have a jack and jack pad to raise the car. 

Note that some care is needed in handling the owners of these cars. Most of the owners I have approached have taken a look at all the tools I am unloading and have questions. Inform the owner what each tool will help you accomplish, and ask the owner if there are any procedures he feels uncomfortable with you performing. Owners that have nothing to hide have never given me static about jacking up their cars and carefully poking around. On the other hand, I have revealed extensive rust and shoddy repair work on one car that the current owner did not seem to know existed. After revealing some of these areas, the owner became somewhat less cooperative!

I also bring a notepad and pen to take notes on what I find. I will locate a section and score it with a (1-4). A (1) means the damage is really bad and must be replaced. This would be a large hole or missing sheet metal. A (2) is usable but will soon need to be replaced. Typically perforated metal (swiss cheese) or bad pitting gets a (2). A (3) would indicate surface rust or cracking in the undercoating. This damage is common and will most likely represent most of the scores given. It is easily repaired by grinding to bare metal and properly painting the surface. A (4) would be given to any area that would not need any attention. These scores makes the decision process a little easier when I review the problem areas. The scores are also useful in calculating a fair price for the car based on needed repairs. 

When you get to the car you need a method to the inspection. There is a possibility that you will look at more than one car. Having a method will usually allow you to do a comparison between different cars as you inspect for rust. 

I usually start with a walk around the car. Its easy to spot problem areas with the paint which could be an indicator of problems. Pay attention to the gaps on the body panels. This is a good time to run your fingers down the gaps. The fingers will tell you if they are uneven. Wrap one of your t-shirt strips on your fingertip. As your finger slides down a gap you can feel it undulate up and down or possibly pinch your finger as the gap narrows. Large unevenness could be signs of accident, or major rust repair. Next I will open the door and pop the latches for the hood and decklid. 

Let's start at the front of the car. Release the latch and open the hood. Careful as the hood shocks may be shot and you could hit your head or worse dent the hood when it clonks the noggin. First inspect the top of the latch panel (nose). The outer corners tend to rust out from clogged seal channels. You should be able to see the last fender bolt. See if the seal is still attached. Check the perimeter of the seal for signs of rust. The hood vent on the cowl is another area to inspect while the hood is up. 

I will assume that you (the buyer) knows what rust looks like. The key is to figure out how bad it is. Pull back the carpet and remove the spare tire. You need to check the front suspension pan in front of the fuel tank, between battery boxes and the boxes themselves. If the owner will let you, unclip the battery hold down and slide the battery out. You should be able to slide it out far enough to inspect the boxes. Many times there will be surface rust. Use the palm of your hand to push down on the metal. It should feel solid. Any squishiness or crunchy sounds means the rust will have to be cut out and replaced. I also look for flaking undercoating. This is usually a sign of rust or potential rust. Also carefully inspect the lateral gas tank supports. These are the structural members that supports the sides of the gas tank. Battery acid spills go directly into this section and cause major damage. 

Open the Smuggler's box and look for rust. If the car has AC you will have to inspect from underneath the car. 

While the hood is up you can inspect the cowl. Slide your hand up behind the hood hinge. Feel for any rust. The panel should be smooth underneath. Continue feeling all the way until you hit the dash. The driver's side is tricky with wiring and emissions controls. I then like to check the lower corners of the windshield as this is directly on top of your current location. Check the windscreen seal. It should feel soft and rubbery. If its hard there may be a leak which will lead to rust. Using the palm of your hand, push down on the trim in the lower corner of the windscreen. Are there any crunchy sounds or does it feel solid? 

We now need to inspect the underside of the pan. Use your jack to lift the car using the a-arm support collar. Listen carefully as you lift for crunchy sounds. If you saw lots of rust from inside the trunk you may not want to lift the car this way. You can also place the jack in the center of the suspension pan. Use the structural box section to lift. There is typically a tow hook here. Don't forget the bottom of the smuggler's box if you could not access it from inside the boot. Inspect the undercoating (especially if the car still has the original factory PVC undercoating) where the A-arm mounts bolt to the body. Stress over time causes the undercoating to crack and allows water to seep in. These stress cracks are so precise that the resulting rust will actually trace its way around the suspension mounts and cause them to fall out. I have inspected two cars (one which was still driven regularly!) in which the front suspension mounts were no longer attached to the car. This condition is a disaster waiting to happen. 

Inspect the underside of the car. Look for rust especially at the seams between the suspension pan, lateral tank support and the inner fender well under the battery boxes. Poke with your screwdriver to see if the metal is solid. This is also a good time to inspect the a-arm bushings to look for wear. If the car has AC look carefully at the condenser box. These typically rust due to condensation from the condenser. This requires more work to repair as there are no suppliers of replacement pans that contain the condenser box. It will have to be custom fitted which costs more. 

Next is to inspect the fenders. I usually turn the steering wheel to one side for this inspection. Turning the wheel to the right allows you to inspect the front wheel wells; specifically the driver front side and passenger rear side wheel well. Vice Versa for the other direction. This is just moving the tire to gain access. Take note to look at the driver's side fender. This contains the fuel filler access. The filler bucket can collect water and rust of the drain is not working properly. 

Areas that usually need attention are the headlight buckets and vertical support by the rockers. Use your screwdriver to remove the headlight or trim ring depending on H1/H4 or Us-type respectively. Look inside the bucket for rust. Also look at the paint between the headlight bucket and turn signal box. Use your magnet to check for previous repairs. Next, reach up behind the bucket and feel for rust. Sometimes the front side is nicely painted and the back side is quite rusty. You will have difficulty reaching up under the bucket as the battery boxes are in the way. If you are inspecting a 1974+ car this will be easy. Shine the flashlight into the areas and visually inspect. You can probe any questionable areas with the screwdriver if its long enough. 

Next, follow along the seam where the fender is bolted on. Look and probe for rust under the undercoating. Fresh undercoating could be covering up problem areas. Follow the seam to the vertical fender support. The top intersection is prone to rust. Follow this support to the lower edge of the fender. Look for rusting at the bottom. The outer rocker butts up against the vertical fender support and is another spot prone to rust. Check the lower trailing edge of the fenders where they meet the rocker. The vertical fender support and back of fender are bombarded with crud from the front tires. Drains clog and create rust. 

Next, work your way along the rockers. If there is trim, push in and listen for crunchy sounds, this is bad. Look at the lower seam of the outer rocker. Does it look sound? Has it been replaced? The welds should be evenly placed and look "factory". If it looks different ask questions about documentation of the repair. Shine flashlight up into drain holes in outer rocker. These drain holes look like stamped openings in the seam. You will have to lay on the ground for this check. What do you see? You should be looking at the inner rocker. It is common to see flaking paint which was a feeble attempt to coat the panels before welding at the factory. These cars are 30 years old and these coatings are no longer doing their job. It is sometimes possible to see damage in here. Look at the jack tube and surrounding metal. Same as above. It should look clean and solid, not rusty. Also inspect door bottoms for evidence of work. The magnet can work well here. 

Next open the door and inspect the sills, latch and hinge post. The section where the sill (top of outer rocker) transitions into the latch panel is prone to rust. The factory leaded this joint. Acid which eventually precipitates out of the factory leading will eat the steel rocker/latch panel joint below. The area is also a shelf on the underside as the latch panel lays on top of the outer rocker. The rear wheel will throw road debris up here, trapping moisture. Use a magnet and your screwdriver here and see if the filled with bondo. It will be less magnetic due to the lead filling. Do the same on the lower edge of the hinge panel (front of the door). 

You now need to inspect the rear wheel wells. See if you can lift the car with a jack. This will also help you look for rust around the jack tube. The car should feel solid when you lift the car. Listen for strange creaks or groans. Crunchy sounds are very bad here. This is usually an indication that the jack tube and support are bad. This is major sheet metal surgery and will require lots of money to repair. 

Lifting the car will allow the wheels to drop giving access to the fender wells. Start by looking at the front fender well years of road spray often wears away the undercoating at the rear/bottom of the front wheel well where the longitudinal/rocker panel begin. Any holes here, no matter how small, are of grave concern. Holes at the leading edge of the longitudinal mean that water has been able to leak into the longitudinal. This will result in extensive damage inside the longitudinal that is impossible to see. Given enough time, the longitudinal will eventually rust out, first at the rear of the car, near the torsion bar tube. This is where the water that entered at the front of the car made its home and did its evil deed! Look up inside rear fender well to the corner of latch panel, B pillar/targa bar and inner/outer fender. Should be clean. If you are looking at a targa, pay particular attention to the attachment points for the targa bar. There is a large drain here that should be clean. If it is clogged, the integrity of the bar is probably compromised. Poke around any cracked undercoating as this is usually a sign of trouble. Follow the seam to the back of the car. Coupes can have rust migrate from the inside out under the C pillar. Go the other direction and look at the back side of the latch post. Do the visual results agree with the front side? You can also now inspect the inner fender support (commonly called the kidney). Look down along the torsion bar tube and spring plates. Water inside the longitudinals will rust out this area. It is now easy to inspect the spring plate bushings for wear. These are typically collapsed if original and will need to be replaced. 

Follow the longitudinals around to the underside by the seam. Then look under the car by the transmission. Look for rust in the longitudinals by the torsion bar tube. This can also be near the rear sway bar mounts (if present, not all T's or E's had them). I would be very cautious about a car with rust in this area. The longitudinals are the structural members that create the strength of the car. Do not drive a car with rust in this area. While you are under the car look at the seam where the floor meets the rear bulkhead and also the bottoms of the rear seat pans. 

I now inspect the top of the car near the engine lid. Look at the lower corners of the decklid. As before, clogged drains usually lead to rust. With the engine bay open inspect the backside of the rear deck/firewall. You can push on the sound pad and listen for crunchy sounds. If the pad is deteriorated or missing you can visually check. You can usually peel down the top corners of the pad and look for rust. Targas are usually not rusty here as water sheds easily off the glass. Coupes can rust easily if water pools in the lower corners of the rear windscreen. Again, check the seal and push down on the corners like you did on the front of the car. 

You can now work your way around the opposite side of the car in reverse order to above. You have now looked at the exterior of the car. Hopefully it has not been neglected or subject to too many harsh winters in its lifetime. If the exterior of the car is very rusty you may want to discontinue the interior inspection. If it seems solid so far, read on...in many cases, you have enough information by now to know it is time to politely thank the owner and go home. 


Inside the car I like to pull both seats forward. Pull the rear carpets and look for rusty floors. Targa tops leak as do coupe pop-out quarter windows. Water easily pools in the back of the floor by the longitudinals and rear bulk head. Rust can also migrate from inside the longitudinals and jack tube. You will find evidence of this about an inch behind the outer seat support near the seam with the floor. There is a small access hole there which is concealed with a plastic plug. 

Next check the rear seats. Water can easily pool under the rear seat bottoms. The seat bottoms are glued in place. If they remove easily it could be a sign of rust underneath. One good thing to check is that the rear deck panel and surrounding areas are not wet. You can press on them and find a squishy sound or feel its a good indicator that the factory horse hair backings are wet. If left wet they are a major indicator of rust. You may want to request removing the rear seats to further check for rust. They can easily be reattached with adhesive. This would be at the owner's discretion.

Next, slide the seats back and pull the front carpets. Inspect the floors especially at the seams. Look for cracking in the tar like floor coating. Pull the front floorboards. If the bottom edges are all rotten its a sign the car gets wet often. A flat screwdriver and 10mm socket/wrench are needed for the driver's and passenger side respectively. Look for rust behind the passenger floor board and around the pedal cluster. Brake fluid from a leaking master cylinder often compromises the paint on the floor pan and causes advanced rust that may not be visible from underneath the car (yet). This is also a good time to look for bad bushings on the pedal cluster. Pay attention to rust inside the center tunnel. Water can collect here and cause major problems. 

If the car is a targa, inspect the top. The targa top should come off easily and latch easily. If not, the tub may be sagging. Check condition of seals while top is off. These are very expensive to replace. Another indicator of a weak chassis on a targa is the door gaps. Look out for even door gaps. The gap at the top rear of the door will close up if the car starts to sag from rust. Look for damage to the paint here as may indicate major sagging if the door and latch panel touch. It is also very important to make sure the longitudinals are rust free on a targa. They support the entire car. 

Congratulations! You now have the skills to inspect an early 911 for rust. If you feel like you need help, contact your local PCA Chapter or look for help on the numerous internet bulletin boards. 

Now check out the gallery of horrible rust. Don't let this happen to your car.