Vintage VW Fuel Pump Flange – An Important Discussion

I was working on another fuel related issue, when Fuel Pump Pressure became the focus at one point. While Insufficient Pressure will be a problem—a plugged Fuel Strainer at the Tank or plugged Fuel Filter or disintegrating Fuel Hose or other supply problems; the contrasting problem can be Excessive Fuel Pressure.

Over the years, Excessive Fuel Pressure has become more and more of an issue. After-market Fuel Pumps which are, perhaps, not manufactured to exacting standards, can fail to deliver Fuel properly. Buying smart—purchasing quality products–often can save the day. While most of us don’t want to spend money needlessly, it does make sense to purchase quality products, especially those products which are so essential to the good/safe operation of our vintage Volkswagens.

A lot of us have discovered the benefit in having our original equipment, such as Fuel Pumps, remanufactured. This preserves the original integrity of the vintage vehicle but also affords a piece of equipment which was specifically engineered for our cars—in our case, the 1967 Beetle.

For this discussion, I am concerned with the Fuel Pump Flange. This is the Bakelite piece which installs directly into the Engine Case. The Fuel Pump then is installed atop the Flange. See the article below which goes into detail about the Flange and Fuel Pump and Fuel Pressure.

The Flange also may be referred to as an “intermediate flange, a “spacer”, a “block” or a “base”. I see that in my former discussion I have called it a “block”.

For all of the years during which I have been driving Volkswagens, I have been blessed by being able to reuse Original German Brown Bakelite Flanges. I still see used examples being sold—some for as little as $5.00 each. They need some cleaning, but they will do their job and do it well.

However, it isn’t always the case that an Original German example is available. That’s when we reach for the computer and purchase a Reproduction Flange. Although most of these seem to be black in color, they also may come in brown.

Over the years, I have been told that the Reproduction Flanges are not manufactured to exacting standards. In order to obtain proper Fuel Pressure, it has been standard procedure to add a second gasket atop the Flange (or even several Gaskets, if by adding one Gasket proper Fuel Pressure cannot be achieved).

Bentley’s Blue Official Service Manual for Beetles 1966-1969 discusses proper Fuel Pressure in Section 3, Fuel System, page 7, where we are told to:

“Place two new gaskets on the crankcase studs for (the) pump and install the intermediate flange on top of them.”

On the following page, page 8, the installer is told to:

“Place one or more gaskets on (the) crankcase studs to adjust (the) push rod stroke, (then) install the intermediate flange on them (the two studs).”

As an aside–I cannot recall ever seeing two Gaskets beneath the Flange. In the case of needing to add Gaskets to shorten the stroke of the Push Rod, I recommend to not remove the Flange, due to the danger of breaking the snout and having to retrieve it from the “bowels” of the engine case. Simply add Gaskets to the top of the Flange to achieve similar results.

Comparing Original Flanges with Reproduction Flanges

All of this brings us to those Reproduction Flanges. Specifically, to their lack of exacting precision during manufacture.

I spoke at length with a representative of a major VW parts retail outlet. He agreed to measure some of the Reproduction Flanges which his company retails. The result was a considerable variance. The height (meaning that part of the Flange which is visible once the Flange has been installed into the Engine Case—see photo #1) varied in measurement from 10mm-12mm.

Measuring some Original German, Brown Bakelite Flanges, which I had on hand, revealed a solid 12.7mm in height–across the board.

I ordered 3 more used Original German Brown Bakelite Flanges from our good friends Dustin and Cassie Carter at Don’s Bug Barn in Athens, Texas. These also are consistently 12.7mm in height.

Barry Blythe of Blythe Enterprises (VW engine builder) in Garland, TX, obliged my request to borrow more used Flanges. He had two used black Reproduction Flanges. These two black Flanges vary in height. Both are shorter than the Brown German Flanges.

Wanting to become more in touch with the contemporary reproduction market, I chose to purchase two new Reproduction Flanges from another large VW parts company. A note here—a lot of, and perhaps most, VW parts companies obtain their parts from only a few warehouses. Usually, a company which reproduces (or has specially manufactured) a part, will say so in their advertisements.

I ordered the “top” (OE) Quality Flange and also a “good” Quality Flange. When my order arrived, I eagerly opened the container. I was shocked to find that the “good” Quality Flange was absolutely useless. Even the “top” (OE) Quality Flange is going to need some corrective effort before it will be ready for use.

The “good” Quality Flange was of varying measurements…it appears that at manufacture, once the Flange was removed from the mold, a worker used (probably) a belt sander to remove casting “burrs” to make a smooth top surface (where the Fuel Pump would sit). The worker apparently did not hold the Flange steady, resulting in a very uneven top surface. The Local VW Engine Builder did some measurements and concluded that the Flange could be successfully milled to correct specifications, since it already was too thick. This Flange bears no maker’s logo but does have the following Part Indication: 040-127-3031—which can be used as a cross reference to the original VW Part Number. Exacting measurement was impossible to obtain but, generally speaking, varied from 13.64—13.01mm.

The “top” (OE) Quality Flange also varied in measurements but was closer to specifications. It, also, will need some milling to bring it into specifications. It bears the VW and Audi Logos and the same cross reference Part Indication as the above “good” Quality Flange. This Flange shows more care during the manufacturing process. However, unless one is proficient and has the proper machinery, the milling needed would eliminate its use—Fuel Pressure would be affected if used as it comes from the parts supplier—even if the casting burrs were removed by sanding. Measurements varied from 12.7mm to 13.16mm.

The two used Reproduction Black Flanges obtained earlier, were carefully cleaned and assessed. One measured 11.175mm while the other measured 12.039mm. Both of these Flanges have a circle where the VW Logo should be, but is absent. Both also bear the cross reference part number. Both also reveal that workers at the manufacturing plant used some sanding device to remove burrs which resulted from poor quality molds.

7 used Original German Brown Bakelite Flanges were obtained from several sources. These were carefully cleaned and assessed. Each bears the VW Logo as well as the original VW Part Number: 113-127-303. The size of the VW Logo varies from quite small to much larger from example to example. Every one consistently measured 12.7mm in height.

None of the Brown Original German Flanges reveals any attempt to remove casting faults. Each clearly has been molded using high quality techniques and each is quite smooth in appearance. Oiling openings are chamfered and smooth—contrasting with the Reproduction Flanges which exhibit crude drillings as well as other crude manufacturing techniques.

More Examples

Almost at the last minute, I was able to buy two more black Reproduction Flanges. Both came from the same Brazilian manufacturer. I purchased them from a major parts warehouse (wholesale).

I asked the local VW Engine Builder to examine these with me. At first glance, they appear to be superior to any of the other Reproduction Flanges which I have been able to acquire—either new or used. Measurements of each revealed disparate heights on each Flange—meaning that one end or side will have one measurement while the other side or end another measurement. Both had been “sanded” in order to remove casting imperfections—unfortunately, this effort resulted in the unevenness of the top surfaces.

Both demonstrate that the oiling holes had been drilled rather than formed during the injection process. One Flange exhibits a miss-drilling where the drill bit skipped along the surface. An examination by looking through the Flange opening revealed drilling burrs on the inside of the opening where the Pump Push Rod travels.

Manufacturing Fuel Pump Flanges

I visited a plastic injection molding plant in Garland, TX, where I live. I interviewed the Manager, who was happy to explain the processes involved in Injection Molding.

He examined the Original Brown German Bakelite Flanges, comparing them with the Black Reproduction Flanges. He agreed that the Reproduction Flange molds not only were poorly engineered but upon release from the molds, some, at least, of the fresh Flanges were carelessly cleaned to remove remnants left on the Flanges from the poorly engineered molds. This resulted in an even lesser quality product.

He deemed, from careful examination, that even these faulty Reproduction Flanges are of some type of Thermoset Bakelite. He explained that Bakelite still is used for many purposes, including in the automotive industry.

One of the things which he noted which helped him to draw his conclusions was the lack of any recycling indicators, which are cast into “plastics” as a rule, in the Industry. He explained that Bakelite products—which cannot be recycled due to the nature of their composition, once melted, become only so much melted material—contrasting with melted plastics, which can be reused time and again as “virgin plastic”.

We discussed creating fresh molds, using vintage German Flanges as models. These, he explained would be costly, into the thousands of dollars. Once production was initiated, using the fresh molds, individual Flanges could cost on the order of $25.00 each (factory price).

With a limited available market, such a venture could be extremely costly, both to the developer and to the consumer.

How Does This Study Affect Us Vintage Air-Cooled Beetle Owners?

To begin with, I would counsel Vintage Volkswagen owners to reuse the Original German Bakelite Flanges. Good, used Original Flanges still are available, as I said earlier in this conversation. Do not automatically think that only new products must be used when rebuilding an engine, for instance. Original Flanges can last for decades.

There is an alternative. If Reproduction Flanges can be acquired which are flat across the Fuel Pump seating surface, but they are shorter than the required 12.7mm, the Push Rod can be milled to a proper length to achieve the correct stroke required to generate the desired Fuel Pressure.

If a Reproduction Flange seating surface is NOT flat, it can be taken to a shop where a suitable surface can be achieved. It has been suggested that a person might be able to create a sanding block to produce a flat seating surface—if the amount of material to be removed is not too great.

Reproduction Flanges which exhibit molding burrs and other small imperfections, might more easily be corrected. Once proper re-surfacing has been accomplished, the
next issue would be, of course, proper Push Rod length.

Reproduction Flanges which are too tall will cause the Pump to produce weak pressure because the Push Rod cannot extend far enough to adequately operate the Fuel Pump Lever.

History of The Flange

David Brown, now retired VW Technician, says—“…the Fuel Pump Block, having no letter designation at the end of the Part Number (113-127-303), means that neither the Part Number nor the Part changed for the full production life of the Part (through 1974). What we know today was the Part used on the first 40 Hp Engines in 1959. BTW—during late 1961, this same Fuel Pump Block was used for the Type 3-1500cc series engine.”

Definition of Bakelite

“Polyoxybenzylmethylenglycolanhydride, better known as Bakelite (sometimes spelled Baekelite), was the first plastic made from synthetic components. It is a thermosetting phenol, formed from a condensation reaction of phenol with formaldehyde. It was developed by the Belgian-American chemist Leo Baekeland in Yonkers, New York, in 1907.

Recognition of Those Who Helped To Make This Study Possible

I made appointments with several people to meet at a predetermined location for a photo shoot and examination of Fuel Pump Flanges

  • Janeva Sulman, our daughter has helped on numerous occasions with photography for Articles and Videos pertaining to 1967 Beetles. She also helps to arrange subjects so that the desired results can be obtained.
  • Barry Blythe, Owner and Operator of Blythe Enterprises is a VW Engine Builder and General VW Mechanic. He agreed to meet us for measuring the Flanges. Thank you, Barry for lending 3 specimens for the study and for ordering two new Reproduction Flanges for us.
  • Geoff Lohmann, Owner and Manager of Christian Brothers Collision, allowed us the use of his office and table space for examination and photography. Geoff owns a ’67 Savannah Beige Beetle.
  • Mike Minshew, Co-Worker at Christian Brothers Collision, sat at the computer to obtain metric equivalents of the inch measurements.
  • Both Geoff and Mike have helped with other 1967 Beetle projects.

I thank each of these people who gave time and effort to help the 1967 Beetle Community!

Posted by Jay Salser

My wife, Neva, and I have been driving and working on VWs since 1976. In fact, we raised our family in these cars. Now, we are retired and enjoy VWs as a hobby. The ’67 Beetle always has been our favorite year. We own a '67 Beetle and a '68 Karmann Ghia.

  1. Really great article, Jay. The ’67 Beetle community thanks you!

  2. More great in depth info and discussion from Jay. Thanks Jay!

    1. Hello, James…Thank you for being a faithful Reader of! I would have had many more photos to illustrate the article, but at the last minute, my Studio Photo program quit on me. I am working to get that solved. The use of Bakelite is not limited to the Flange–it also is used for the Distributor Cap, the Distributor Rotor and the Spark Plug Connectors–probably more than I can think of at the moment. Keep enjoying your VW! jay

  3. Hi Jay. Yeah we did back and forth emails discussing the flange thickness differences and variations across 3rd party suppliers that caused my new pierburg floods my 61 type 1 carb. Thanks for your support at the time. BTW one of the supplier now offers much thicker upper gasket. Helps me a lot to reduce total 15 “thin” gaskets to reach 13mm and 2.8 psi. Cheers

    1. Hello, Lukas–It is good to hear from you! I suffered with you during all of the problems which you were having!!! One would think that with today’s technology, parts would be precise. The Fuel Pump Flange is not a difficult part to produce. You have done a lot of research–I applaud your efforts! Keep up the good work and keep loving your VW Beetle!

  4. Hi Jay, another very good tech article. So much valuable information. I went down the road of dialing in the correct fuel pressure many years ago. Also, came up with a fuel press gauge arrangement so I could measure the fuel pressure at the fuel pump to help get the correct pressure. Thanks again for the great article and details. Merry Christmas.

  5. Hello, Richard. Good to hear from you! Good for you for taking into account this “villain” we call Fuel Pressure. Once you have achieved a “balance”, probably all things will stay pretty well tuned. Wear seems not to be a big problem. But, deterioration of rubber diaphragms will eventually cause a reassessment and renewal effort. Y’all have a great Family Christmas, too, Richard!

    1. Good info, Jay!

  6. Hello Jay ! Thank you for sharing this valuable information to the VW community. By experience, I learned a lot on a broken flange, its tricky removal and with your guidance, obtaining a proper VW one with the proper specs at Don’s Bug Barn. Best regards Jay and Eric!

    1. Hello, Guy.. …I recall vividly your removal of the broken flange piece from your engine! You did a really good job of that tricky maneuver! Good thinking! Eric and his wife make this Site available and, as you say, it has proven to be valuable to many of us.
      I return to read some of my articles to refresh my own memory! Thank you for reading and commenting, Guy! jay

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