Great article, Jay. I’d have to agree, lack of care is the # 1 reason so many vintage VW fires happen. With some simple love and care, we can help keep these gems on the road for the next generation to enjoy. Keep an eye on those fuel lines! -ES
I continually receive questions and comments about Fuel Filter Placement. You will find a couple of Articles on 1967beetle.com regarding the subject.
The common warning is: Fuel Filter in the Engine Compartment? You are heading for a Fire!
So Beetle Owners hasten to place their Fuel Filters under the car near the back wheel or just under the Gas Tank.
And…we believe that we now are safe from an Engine Fire. Period!
This misconception is bound, sooner or later, to wreck havoc. Because we Beetle Owners become complacent.
Beetle Engine Fires generally have to do with a Lack of Maintenance. Here’s why:
Possibly the Number One contributor to an Engine Fire is:
Failure of Fuel Hose:
- Installation of the incorrect Fuel Hose. The stock metal fittings in our Beetles take a 5mm Inner Diameter Fuel Hose. American fuel hose has a larger than 5mm Inner Diameter. Thus, when a clamp is installed, the American hose can become “puckered”, giving rise to the possibility of leakage.
- Installation of correct Fuel Hose. The correct, stock Fuel Hose has an Inner Diameter of 5mm, which accommodates perfectly to the stock metal Fuel Lines of the Beetle. Fuel Hose should be clamped to the metal Fuel Lines, using care not to clamp so tightly that the Fuel Hose is distorted. The Clamp wants only to be firmly fixed so that the Fuel Hose cannot be pulled off the metal tubing and won’t leak.
- Regular Inspection of Fuel Hose. Here’s where most of us fall short. We do not regularly inspect the Fuel System of our cars. I hope that you are keeping a Written Maintenance Record of your car. This can be kept on a computer or in a notebook stored in the glove box. No matter the method—keep a meticulous Maintenance Record.
And one of the most important items on your check list should be the Fuel System. Especially Fuel Hose in the Engine compartment and especially Fuel Hose from the Fuel Pump to the Carburetor.
Know when Fuel Hose in the Engine compartment was installed. We forget these things. What may seem to be only a year, quickly turns into 3 years or 5 years. Fuel Hose weakens due to several factors: Age, Heat, Vibration, Chafing and Ethanol.
Fuel Hose that has been in the Engine Compartment for more than a year probably should be removed and new hose installed. This is so easy that most of us can do it in a half hour’s time.
Heat is the enemy of many automotive components—but especially of rubber. The Core of the Fuel Hose is rubber. Heat hardens rubber and causes eventual failure. Vibration contributes to the demise of hardened rubber.
Often, Fuel Hose comes into contact with other parts in the Engine Compartment. Rubbing, or chaffing, can cause even good Fuel Hose to wear prematurely. Mitigate losses by routing Fuel Hose so that there is a minimum of chaffing.
Now, we come to the Hidden Enemy—Ethanol in the Gasoline. Ethanol causes most rubber products in our Beetles’ Fuel Systems to deteriorate. Unfortunately, we cannot find truly Ethanol-resistant rubber products for most of our VW applications. It is up to us to monitor our Fuel Systems in order to avoid this Unseen Predator.
Signs of Fuel Hose Failure:
Frayed Cloth Covering of Fuel Hose is a sign of deterioration. Change the Hose.
Cracking Rubber seen at the end of Fuel Hose is cause for concern and replacement is in order immediately.
I have on my workbench specimens of Fuel Hose in varying states of deterioration. One specimen has good (in appearance) woven covering but when bent, a crackling can be felt. Meaning that the inner rubber core is old and brittle.
Here are a couple of illustrations which come to mind in my experience:
A customer stopped at the house for a part. When questions arose about the part, I asked if he had driven his Bug to the house. He told me that he had parked it out front. We went to the car and opened the engine compartment in order to verify the part which he needed. I put a finger onto the Fuel Hose where it leaves the Fuel Pump for the Carburetor. Immediately, the Hose became wet with Fuel! I told the customer to drive his car into the driveway, where we changed his Fuel Hose. I think that we avoided a catastrophe!
At some later date, I was inspecting my own ’67 Beetle and found a similar condition. You can bet that I went for the new Fuel Hose right away. I didn’t say…”I’ll change that one of these days.” I changed it then and there!
What—Another Cause of Engine Fires?
Now, I want to talk about a cause of Engine Fires that vies with flawed Fuel Hose for the Number One Cause of Engine Fires—it’s the Brass Inlet Tube of the Carburetor. This is the Tube where Gasoline enters the Carburetor. The Fuel Pump has pressurized the Fuel and sent it to the Carburetor Bowl. That means that there is at least 2.8 pounds per square inch of Fuel Pressure leaving the Fuel Pump.
If you were to remove the Fuel Hose at the Carburetor, with the Engine running, there’d be an awful lot of Gasoline squirting onto the Engine—immediately!
Here’s what happens. Over time, the pressed-in Brass Inlet Tube at the Carburetor can loosen due to vibration. And, due to pushing and pulling on the Tube when installing or removing Fuel Hose. And from cleaning the Carburetor from time to time.
It is possible that having the Fuel Filter located between the Fuel Pump and the Carburetor can add a dimension to the situation by putting a bit of extra weight/stress on that short length of Fuel Hose.
Over the years, I have made it my practice to “stake” around the Brass Inlet Tube by using a tiny center punch and a light-weight hammer. By placing the tiny center punch at several places at the base of the Tube (where it enters the Carburetor) and lightly taping with the hammer, a tiny indentation is created at each of those places. This expands the pot metal of the Carburetor, tightening it around the Brass Inlet Tube. This creates a more firm fit of the Tube.
There is a better method, however. This involves removal of the top portion of the Carburetor and taking/sending it to a qualified shop for the following procedure.
A technician will remove the original Carburetor Brass Inlet Tube. The orifice then will be drilled to a specific diameter. Once the orifice is the correct diameter, it will be tapped to produce threads to receive a Threaded Brass Inlet Tube.
A shop in my area uses a special sealant on the threads to ensure a sealed fit with no leakage.
The Tube part of this Threaded Fitting has what is known as a “Barb”. The Barb is a raised ring which grips the rubber core of the Fuel Hose when the Hose is pushed onto the Tube.
Although the Tube has the Barb, I recommend a Clamp at this point as well.
Once the Threaded Tube is properly installed, it never should loosen and fall out. Done!
Occasionally, the High Pressure Tube on the Fuel Pump also will loosen and fall out. The same procedure that is described above can be used on Stock Fuel Pumps 1966 through 1970.
Here’s the Trivia Question and Answer for the day:
Why does Fuel Hose for Air-cooled applications have a woven exterior layer? The answer is that the exterior layer helps to keep the Fuel Hose cool. It forms an insulating barrier against heat.
I want to thank Doug Smith of R & D Engineering for his advice and the Barbed Inlet Tube prop for this Article. Doug has been very supportive of the Volkswagen Community locally and farther afield.
His shop has installed a Barbed Fitting into the Carburetor of one of the Salser cars.
I’m always grateful to my wife, Neva, for concentrating on photography for these Articles.