240L31
Club Member
As my electrical fuel pump installation failed due to too little flow, I decided to rebuild the stock mechanical fuel pump. I ordered OEM parts but still had a similar looking american fuel pump. As I was curious, I took it apart and pictured the differences.
Findings:
- Castings are identical
- Afermarket rubber diaphram looks better (there's a reinforcement webbing layer in the middle), T style plunger is identical in size
- Aftermarket main spring is slightly stronger (most likely as the OE one settled a bit)
- Aftermarket helper spring is slightly weaker (1.0mm vs. 1.2mm OE)
- Aftermarket valves are pressed in place and can't be changed. Additionally, the movable valve part is a rubber disk as opposed to a solid disk (OE)
- The aftermarket pump has a 8mm inlet and 6.5mm outlet - this is a big plus! As the fuel rail is 6.5mm and the fuel filter 8mm
All in all the aftermarket pump is a great parts donor!
Findings:
- Castings are identical
- Afermarket rubber diaphram looks better (there's a reinforcement webbing layer in the middle), T style plunger is identical in size
- Aftermarket main spring is slightly stronger (most likely as the OE one settled a bit)
- Aftermarket helper spring is slightly weaker (1.0mm vs. 1.2mm OE)
- Aftermarket valves are pressed in place and can't be changed. Additionally, the movable valve part is a rubber disk as opposed to a solid disk (OE)
- The aftermarket pump has a 8mm inlet and 6.5mm outlet - this is a big plus! As the fuel rail is 6.5mm and the fuel filter 8mm
All in all the aftermarket pump is a great parts donor!