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There are four non return valves on the pump but only two are of the ball bearing type and these are located on the pressure pump inlet and outlet. The photos below show the correct orientation of the ball and cross cut bush (top photo is the outlet, bottom is the inlet). They are located in opposing orientation such that the inlet valve seals and the outlet passes when pressure is applied to the pump and vice versa. The other two NRVs are on the vacuum pump inlet and outlet but these are comprised of thin hexagonal shaped pieces of rubber.

These are the NRVs from the vacuum pump inlet & outlet

111Robin wrote: ↑Wed Oct 25, 2023 1:58 pm There are four non return valves on the pump but only two are of the ball bearing type and these are located on the pressure pump inlet and outlet. The photos below show the correct orientation of the ball and cross cut bush (top photo is the outlet, bottom is the inlet). They are located in opposing orientation such that the inlet valve seals and the outlet passes when pressure is applied to the pump and vice versa. The other two NRVs are on the vacuum pump inlet and outlet but these are comprised of thin hexagonal shaped pieces of rubber.

Thank you Robin, that makes sense, unfortunately then I'm missing one of the NRV on the Vacuum pump, it appears to be some kind of Bakelite material....

I think you could just experiment with an alternative material for these. Are you sure one of them isn't stuck in the valve ?. I think I had to persuade mine to come out when I stripped mine.

111Robin wrote: ↑Wed Oct 25, 2023 3:22 pm I think you could just experiment with an alternative material for these. Are you sure one of them isn't stuck in the valve ?. I think I had to persuade mine to come out when I stripped mine.

Thanks again Robin, I'll check that once I strip it down again to fit the new seals which are due shortly...

Andrew 1967 suggested I contact All Seals in Norfolk and they have come up trumps: Here are the details for anyone looking for new seals:


allseals (East Anglia) Ltd
17 & 18 Roundtree Close
Roundtree Way
Norwich
NR7 8SX
Tel: 01603-486851

Email sales@allseals.co.uk www.allseals.co.uk

I extrapolated information from earlier posts from the Hallite and MFP part no's here then are the reference no's of the seals from the above company:

Pressure seal: Hallite Ref - Series 511 part no: 8806510 - All seals part number: IUP 075 125 025 EU Polyurethane U Ring

Vacuum Seal: Hallite Ref - Series 58 part no: 6504850 - All seals part number: IDD 150 100 062 (Black Rubber & Fabric Seal

MFP seals: XP-250-01.000-375. (BU2145) - All Seals Part number: IUP 100 150 037 EU Polyurethane U Ring

That's great news .. not tried them myself for these seals but if all good I'll get a set for my second pump.

What is the specification of the nylon hose and where can it be obtained?

Something like this will be fine.

5/16 Tube is good to 560 psi working pressure & 2100psi burst.

https://www.ebay.co.uk/itm/323774574654 ... R6aD2__tYg

111Robin wrote: ↑Wed Oct 25, 2023 3:22 pm I think you could just experiment with an alternative material for these. Are you sure one of them isn't stuck in the valve ?. I think I had to persuade mine to come out when I stripped mine.

I've checked the housing for a possible missing Bakelite valve - nothing there. I wonder however whether there were any modifications to this particular 'side' valve. The design of it seems more set up for use as a ball bearing valve a little like the slash cut fitting on the pump side..

I fitted one (ball bearing) and tried it and certainly the valve works when sucking on that pipe - that pipe incidentally is for the vacuum gauge - any thoughts? Oh and on one of the many images I've found they do show a third ball bearing.. I appreciate a difficult one to answer!

I'm not sure about the third ball Richard but I don't think it's intended for the vacuum valve. The references below are from (I think) the chap in Australia who has produced a lot of information on the pumps. On my vacuum valve the inlet and outlet ports were flat bottomed holes so wouldn't work with the ball as a valve. Maybe there are different versions of the valve, it wouldn't surprise me.

Here is the explanation for the third ball.

111Robin wrote: ↑Wed Nov 01, 2023 6:31 pm I'm not sure about the third ball Richard but I don't think it's intended for the vacuum valve. The references below are from (I think) the chap in Australia who has produced a lot of information on the pumps. On my vacuum valve the inlet and outlet ports were flat bottomed holes so wouldn't work with the ball as a valve. Maybe there are different versions of the valve, it wouldn't surprise me.

Thank you for that Robin,

I did come across the Australia diagram, the curious thing on the side outlet (to the gauge) was that it differed from the lower vertical outlet in that it wasn't flat it has a slightly raised outlet like a cup that the ball sits in perfectly - I should have taken an image. So the flat one would if trying to fit one - been left sitting on a small raised centre. With a sucking test on the pipe to the gauge it (reduces) when sucked I'll see what happens when I come to use it.

I didn't come across another ball bearing and must investigate the high pressure connector - thanks again...

I'm restoring the vacuum side of my pump (pressure side is already all restored) and I managed to find/build all the needed parts besides the new diaphragm for the valve. Does any one know what is the partnumber for such a diaphragm by saunders?

Does someone has a photo of how does the no-loss connector look like inside? I have the spare copper washer and the 19g703c bulletin which says to remove the "threaded union" after removing the wire circlip and the collars...
UPDATE: there are several types of no-loss connector. The one that I have on the machine is one without the threaded tip and without the washer.