Measure the I.D., O.D., and length of the gaps where the seals go, and then come up with something to fill the openings, with a bit of over sizing so they will seal. When you get the numbers of the openings, you might post them here, the answer might be easy for some of us when we see the numbers...
Cheers Bob. I stripped the whole thing down today and some of the washers are in a better condition so I was able to see what was going on.
Each of the seals is made up of 4 separate washers, three fitted in the barrel of the compression fitting, then a sprung split ring that locates in a groove on the tube and then one more washer seating inside the union. Easier to show in the following photograph than to describe:
The washers are don't appear very uniform, but probably distorted after 50 years in compression. Approx dimensions are OD=0.71", ID=0.5" and width is 0.1" - one face of each washer appears to be concave, but not sure this would be essential. I shall have a browse around and see if I can find any suitable sealing washers, but worst case I',m sure I can cut/improvise some from a suitable piece of silicon or nitrile rubber hose.
I shall probably customise the tap and fitting to connect two 1/2" BSP fittings, then I can mount some of the modern flexible outlets and retain the riser and tap.
I've now made and replaced the corroded foot plate of the cooling pump, using stainless rather than the original aluminium, and soldered up a cylindrical stainless mesh filter to collect and prevent the swarf recirculating. All working rather nicely, but it does spray a lot of suds around the workshop, particularly when working up towards the chuck. To catch the worst of the spray I've now fitted a rubber curtain to my chuck guard, which helps keep the floor and my feet dry