Vintage Werks offers rebuilding service for mechanical fuel pumps of various European manufacture, principally Solex, Pierburg, and Fispa. While most of our pump service centers on pumps for VW Beetle and Transporter (25hp, 36ph, 40hp and some later pumps), and Porsche 356, 912 and 911 models, we also service pumps for early Mercedes, Alfa-Romeo, Volvo, Fiat, BMW and other makes.

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PHOTO 1. Diaphragm BEFORE restoration.

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Vintage Werks fuel pump restoration involves complete disassembly of each fuel pump we receive followed by a thorough cleaning of all parts.  Cleaning includes a solvent wash and for metal parts, blasting with a very fine resin media that polishes the surfaces without unnecessary abrasion. Special care is exercised in bead blasting fuel pump body elements to remove dirt, oxidation and discoloration while resurrecting the original casting finish and imperfections. Smaller hardware parts such as machine screws, clips, washers and nuts if reusable, are likewise cleaned, bead-blasted and then plated in clear zinc. Inlet and outlet valves and valve seats, which meter flow through the pump to the carburetor, are removed and resurfaced to assure proper seating. The fuel pump mating surfaces are then carefully faced to create flat surfaces that will improve seating between the top and base and between the base and the resistex pump block.  All larger parts are washed thoroughly again in solvent to remove any residual blast media.  The original diaphragm is restored by grinding off the rivet which secures the old gasket material, drilling and tapping a hole for a machine screw to install a new gasket.  New diaphragm gaskets precisely cut to original dimensions from material of similar weight and performance characteristics are then fitted to the diaphragm post. The fuel pump is then reassembled with the restored diaphragm and tested to assure the internal valves are seating to allow proper pump function.

About the Fuel Pump Base

Fuel pump bodies for both the early VW and Porsche engines consist of lead-zinc metal castings which are relatively soft yet brittle. With age, they can oxidize and when subjected to continual pressure as from the pushrod, they can warp. On virtually every fuel pump we have seen. the pump base is warped which in turn creates the nearly ubiquitous oil leakage around the fuel pump commonly associated with the 25 hp and 36 hp VW engines but also found on later engines. While we resurface the fuel pump base to create a better fit between it and the resistex base, you must be aware that warping of the base will resume as soon as the pump is put into service again although this progresses relatively slowly. The base can of course be refaced periodically to minimize the affects of the warping in terms of oil leakage. However, eventually enough metal will be removed that the base will no longer be serviceable.


PHOTO 1. Diaphragm AFTER restoration.

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About the Diaphragm

In our experience, the part which most often causes a problem in the fuel pump is the diaphragm. With age, it hardens and cannot be actuated or develops a leak in which case it fails to hold pressure. At one time of course original German rebuild kits with quality replacement diaphragms were available but these are essentially no more. About the only rebuild kits currently available are manufactured in Brazil. Put simply, our experience with the diaphragms in these kits has been disappointing--they utilize material of inferior quality and weight and are cut to incorrect dimensions. As a result, leakage or premature failure often result.

To avoid these problems, we refuse to use commercial fuel pump rebuild kits. Instead, we remanufacture the original German diaphragms using gasket material of like quality cut to original dimensions. This is in the best interest of the customer to restore proper fuel pump function, maintain originality and keep costs manageable. In the process, we make the diaphragm indefinitely rebuildable by replacing the central rivet with a machine screw which can be removed and new gasket material put in place at any time. To accommodate our customers, we offer precut gasket material separately for those who which to carry a spare.

Vintage Werks charges a minimum labor rate of $145 to $175 for a basic fuel pump rebuild. Any parts used or special machining to repair damage or wear, as well as nominal fees for plating services and shipping, are additional. Your fuel pump is tested after reassembly to assure the diaphragm is providing pressure within the appropriate range and that the one way valves are seating properly. This way the pump will work on installation provided you follow installation procedures outlined in the Bentley manual. Failure to follow proper installation procedures on your part may void any warranty on our part. Your pump is return shipped to you with flange gasket ready for installation.