[hypoxia]

I have rebuilt one, a long time ago. If I remember correctly, all the seals are normal o rings. I don’t have a record of their sizes. Easy on the lube when reassembling, there are a few small orifices that you do not want to occlude.

Our coach has a built in shutoff valve to the multiplier.

Mine also has a shutoff valve which is probably a good idea to install while it is torn apart.  But then, I have installed shutoff valves on a lot of supply lines.  I don't consider brass NPT fittings very susceptible to leakage but some folks think adding any fitting is not worth the risk.