Fuel Pump Restoration

VINTAGE FUEL PUMPS RESTORATION SERVICES

In addition to distributor rebuilding, Vintage Werks offers a rebuilding service for original German fuel pumps manufactured by Solex of the type used on 25 hp and 36 hp VW beetle and transporter engines and early 356-A and pre-A Porsche models. More recently we have added rebuilding of Pierburg fuel pumps for 40hp and 1300/1500 VW engines as well as mechanical pumps used on later 356, 912 and early 911 Porsche models.

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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 resurecting the original casting finish and imperfections. This is in contrast to many other rebuilders who either do not effectively clean the bodies or use abrasives or pressure settings that ruin the original appearance. Smaller hardware parts such as machine screws, clips, washers and nuts, if reusable, are then plated in clear zinc.  The fuel pump mating surfaces are then carefully faced to create a 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.

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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 $95 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.