Oil pump piston leaks

[LuisPaz]

Hi
I have observed that my pump when it is working, leaking oil through the pistons.

The pump should work without oil leaks as seen in this Ariel 500?

https://youtu.be/0_30mWuSqcw

[LuisPaz]

That cooper pistons are correct?

[nevhunter]

Someone may have had them copper plated to rectify the wear. They are made of steel. If there's any slack you can actually see, it's worn too much. It only needs the end to be worn and it won't pump reliably especially when hot. Some of the springs that seat the balls that are supplied are not correct. The straight ones are for a later holder (The square bit that screws in to the body.) The originals have a tapered spring that is quite light, and goes small end in first (against the ball) .They sometimes tend to jamb in the threads. The balls are a weird size as well and can wear oval and seat unreliably.
Remove the pump and put some thin oil in the holes and push the plungers in further by hand. They both should "POP" quite readily, even with a 50/50 kero/oil mix. Nev