Thanks guys, lots to think on there.
I realised I had overtightened the Perspex cover until it bent, this won't happen with the metal cover but also proves the o ring as a wee bitty too thick and the 1.5 will hopfully do the trick.
Having backed off the bolts a tad so they're only just nipped up, I re-tested it and it passes the 6 bar pressure test.
Yes please and thanks Paul, yes a spare cover would be good for pressure testing.
Pressure testing will rule out this seal from the list of potential leak points.
That just leaves the body and the nuts, the body has a gasket so "shouldn't" leak, the o ring mod I thought was to improve pump efficiency? although the double o ring idea might help keep the oil in.
That leaves the "special" nuts. I used the yellow sealant on plain nuts, so they maybe need attention. Nylocs and dirko maybe.
I was told by a reputable engineer just today, that you should put the cover gasket on dry and the oil in the groove will wet it and expand it. sounds plausible to me.
Cheers for having changed the pump in situ Paul, that gives me hope, good point about the water bottle, that'll save draining the coolant.
I'll see what I can do about sealing the distributor tower when I change the temp sensor. shame it's not a removable cap. oh well, one more drip.
The bus is booked in for it's MOT a week today, I asked about oil leaks and he said "if it drips, it's an advisory, if it pours it's a Fail." so that's good, what about rust? I asked, he just laughed and said "well it's a VW camper..."
So I have a week to fix the oil leak, I'd rather do it before Yorkshire.
'86 1.9 DG, 4 spd, tintop, camper conversion.
Split case club member.