Thursday 16 May 2024

Pierburg fuel pump rebuild

Apologies for another long absence, it seems that I may be unofficially trying for the longest classic car restoration in history. Maybe I should reach out to Guinness and have it recognised as such when Gretchen finally gets back on the road in 2050? Anyway, I will explain in due course why things seemingly stalled yet again, but it is an exciting story for another time. 

Back to business. The last time I updated on reviving the old engine and getting her purring once again. That was a thrill and since then I have been thinking about reinstating some original components as a lot of the ancillaries currently installed are inferior aftermarket parts. Back when I was a young student (and thus dependent on the car as my daily driver) my motivation was always just to keep the car on the road. So when things would fail I would simply buy the cheapest generic replacement part and toss the old parts as though they were worthless scrap (little did I know!). Fast forward to the present day and I am acutely aware that original VW parts are far superior and fortunately there are serviceable parts available to enable the rebuilding of certain things.

So, I picked this original Pierburg fuel pump up from a swap meet for £10. It is period correct to my car (manufactured in 1965) and was a prime candidate for a rebuild:


 The old pump was stripped down:


I than ran it through the ultrasonic cleaner, which brought it up almost like new:



The rebuild kits are comparatively expensive, but I am grateful they exist:


 All parts laid out and ready for assembly:


It was then a case of checking the serviceability of the used parts and replacing the old stiff and cracked diaphragm:
 

Everything went back together easily and it occurred to me just how relaxing this part of the process is:


To set the main diaphragm to the required assembling position (as stipulated by VW) I used a bolt clamped firmly in the vice and ensured that it protruded exactly 14mm:


With the top portion only loosely held on by the machine screws, I clamped down the base of the pump with the bolt pushing up on lever with the correct lift. I was then able to tighten down the machine screws which clamps the diaphragm into the correct position:


Rebuilt and looking great. I will fit this up to the engine soon and give it a test run, just need to renew my old fuel hoses first: