1966 Ambassador water pump leaks

We just recently purchased our first AS. It's a 1966, 28' International Ambassador. The trailer has not been used for two years. It was winterized with RV anti-freeze throughout. The "city" water system works great but the water pump for self contained mode leaks at the base where the two valves (intake/output) is. As per the original manual I cleaned the "very clogged" screen. The pump works great other than the leak. Also per the manual I removed the (4) screws that is on top of the valves, intake/output. I cleaned all of the debris and torqued the screws evenly but can't stop the leak. I've cleaned and re-torqued (3) times to no avail.



Can I apply some Permatex form-a-gasket around the surfaces ? There is no gasket between the two surfaces. Any advice is appreciated.



Thanks,

Danny