Basement Project
Posted: Tue Mar 14, 2023 1:09 pm
This was a miniature project I could do in the basement. Last Fall, I got a Pierburg fuel pump at a swap meet. Then, about two weeks later when I was cleaning out my garage, I found two more -- probably from about 35 years ago. I decided to buy one of the WW rebuild kits that everyone complains about to see if they really are as crappy as people say. So, a little while ago, I rebuilt one of the pumps in the warmth of my basement -- figuring that the cheap pump I have in the bus will eventually jettison the lever arm shaft.
Pump before disassembly.
How the lever arm engages the diaphragm pull-rod (sorry about the photo):
Disassembled: The only parts I ended up replacing were the main diaphragm, the cut-off diaphragm with spring, the filter, and the lever arm spring. Everything else didn't need replacing or was not properly functional from the kit.
The kit.
The replacement diaphragm and spring looked identical to the original, bit I've heard that the new spring is too stiff and results in fuel pressure that's too high. So, I took the springs off and compared -- the new one was definitely stronger, so I cleaned up the original and put it on the new diaphragm.
Original spring on right:
The new diaphragm/old spring connected to lever arm/shaft after casting surface for the diaphragm was cleaned. I used the new spring for the lever arm.
I used the original shaft, because the new one was too large for both original and new e-clips! The problem was, the new e-clips were too large for the original shaft, and the original e-clips were sprung (probably from removing and reinstalling). So, I used new 4mm clips I had in my stash.
Left: New from kit (way too large); Center: Original (slightly loose); Right: New (good fit)
Pump before disassembly.
How the lever arm engages the diaphragm pull-rod (sorry about the photo):
Disassembled: The only parts I ended up replacing were the main diaphragm, the cut-off diaphragm with spring, the filter, and the lever arm spring. Everything else didn't need replacing or was not properly functional from the kit.
The kit.
The replacement diaphragm and spring looked identical to the original, bit I've heard that the new spring is too stiff and results in fuel pressure that's too high. So, I took the springs off and compared -- the new one was definitely stronger, so I cleaned up the original and put it on the new diaphragm.
Original spring on right:
The new diaphragm/old spring connected to lever arm/shaft after casting surface for the diaphragm was cleaned. I used the new spring for the lever arm.
I used the original shaft, because the new one was too large for both original and new e-clips! The problem was, the new e-clips were too large for the original shaft, and the original e-clips were sprung (probably from removing and reinstalling). So, I used new 4mm clips I had in my stash.
Left: New from kit (way too large); Center: Original (slightly loose); Right: New (good fit)
