I have not actually done it but I secured all the parts & started to measure things up, .... & it isn't quite that easy.

The idea is to use the 'L' series internals in an 'A' series pump body, so the first things to measure are the two shafts.
You will find that the L series shaft is too short & it measures 1/2" in diameter. [well, mine did]

The A series shaft is 12mm in diameter, which is smaller, so the hole in the pump body will be smaller than the L series shaft.

The length problem can be overcome by pushing out the pin in the rotor, then pushing the shaft outward untill the protrusion matches the A series & filling the resulting hole in the bottom of the rotor with silicon or some other suitable material, but you still need to be able to get it into the A series pump body. This can be done by enlarging the hole or machining down the shaft.

If you enlarge the hole in the pump body, then you will also need to enlarge the hole in the drive gear so it will fit the larger shaft size.


If you machine the shaft down, then you can only machine the part that goes into the pump body because you will still need the larger diameter inside the pump rotor to hold it

Next, you need to realise that the L series pump is driven by a tang on a drive shaft. This means that the end of the shaft where the drive gear will now sit has a slot in it which will weaken the shaft right where it needs to be dimentionally stable in order to properly secure the gear.

My preferred solution is to have a new shaft made up that has the proper 1/2" diameter for the rotor to sit on & the remainder at 12mm diameter where it fits into the pump body & of the correct length for the A series application.

This way it all goes together like a factory job.

As for the spacer to allow the use of the L series rotors, .... that's your problem.