Churchill Hydrolastic pump

[111Robin]

Nice work. I'll have a go at mine at some point.

[Peter Laidler]

Just move down here Rob and we'll do it together! Photograph it along the way and put it all up on the forum. - and offer a rebuild service! . Probably a bit to cold for me to move up there!

[spoon.450]

I'll donate mine if anyone wants a project as Peter suggests.......so long as I can borrow it when done

[111Robin]

Just move down here Rob and we'll do it together! Photograph it along the way and put it all up on the forum. - and offer a rebuild service! . Probably a bit to cold for me to move up there!

Just think though Peter, you could probably buy a country estate up here if you sold up, complete with forest to keep the wood burner going. Then employ me as your lachie

[iain1967s]

Pressure side is working now. I had the outlet restrictor of the one-way valve upside down, so the solid face was blocked by the ball bearing on the pressure stroke instead of allowing fluid through the cross-cut flutes.

For anyone else attempting a repair, the assembly order of the pressure side from top to bottom is:

Overflow hose to top of tank
Black handled brass valve
Threaded union
Long banjo bolt
Dowty washer
Banjo splitter to gauge and pressure hose
Dowty washer
Long restrictor - cross cuts facing downward
Ball bearing
Pressure pump outlet
Pressure pump body
Pressure pump inlet
Ball bearing
Short restrictor - cross cuts facing upward
Dowty washer
Banjo on inlet hose from bottom of tank
Dowty washer
Short banjo bolt

Now all I need to do is fix the leaky Schraeder valve connectors at the other end of the hoses. I think the rubber grommets are replaceable so that shouldn't be too hard, and worst case equivalent parts are still available new.

[111Robin]

Just noticed that my pump only has a single hose and the instruction plate designates it as a single hose pump. It also refers to an internal changeover valve, automatically switching between pressure and vacuum as opposed to switching hoses. Another complication to deal with.

20170808_194226 by robin_derrick, on Flickr

[iain1967s]

Could anyone who has a two hose UK model pump possibly email me a good quality photo of the top instruction plate please?

Mine has no plate and the only one I can find online is for the single hose version. I want to try and get one printed up on plastic sheet to finish my refurb.

Email address is iwbarker at mac dot com

Thanks !

[minimk1man]

I have emailed you a scanned image of the instruction plate on mine. Hope its OK for you.

[iain1967s]

I have emailed you a scanned image of the instruction plate on mine. Hope its OK for you.

Thanks Trevor, that's exactly what I needed. I should be able to use it to create artwork for engraving a new plate at one of the online services.

Update: PDF and MSWord file of my recreated placard attached, in case anyone else needs one.

[111Robin]

So is the twin hose pump the earlier version, later superseded by the single hose ?. I had never seen the twin hose style until now.

[cheleker]

And I've never heard of a single hose one before!

Supports my saying: The more I know about Minis, the more I know I don't know about Minis.

[minimk1man]

I agree Chuck.

I have 2 pumps here and both twin hose. You never stop learning.

[BLT]

I have emailed you a scanned image of the instruction plate on mine. Hope its OK for you.

Thanks Trevor, that's exactly what I needed. I should be able to use it to create artwork for engraving a new plate at one of the online services.

Update: PDF and MSWord file of my recreated placard attached, in case anyone else needs one.

Iain, just sent you a pm.

[BLT]

Found a cap that fits if anyone else needs one.

Jerry Can Cap for 1412 / 1415 - Blue 5001B ROYAL
eBay item number: 322444925319

[Seamist Green 1100]

I wonder if Inpress Plastics was the original supplier of tanks?

[Seamist Green 1100]

Something I discovered on my pump was the vacuum Schrader chuck is a Turner "Renrut" chuck off a Kismet foot pump.

[iain1967s]

Sometghing I discovered on my pump was the vacuum Schrader chuck is a Turner "Renrut" chuck off a Kismet foot pump.

Yeah, I've been tracking a few of those on eBay. Trouble is the pumps are also collectors items so it gets expensive real quick...

A modern alternative is to use the couplers used for refilling nitrogen in aircraft landing gear struts. There are two designs available, one with a 1/8" male and one female. Both have separate Schrader thread clamps and screw-in pin depressors, which is the whole point of the original adaptors on both sides of the pump. Obviously if you have a single line pump you only need one of these - they aren't too cheap...

Note that the thread clamp on these strut couplers uses a copper washer to seal against the top of the Schrader stem, so it will need tightening down with a spanner to seal properly, not just finger tight as with the original coupler. I might try using a small O ring instead of the copper washer.

The male version plus a 1/4" to 1/8" reducer seems to fit well for the pressure side of the pump. Note: It feels like it will screw directly on to the thread of the bleed screw even though one side is NPT and the other is BSP, but if you want to do it properly use a thread converter.

I haven't tried it but I think the female version with a 1/8" NPT to a hose barb would be a good replacement for the renrut on the vacuum side, since that connects directly to the 5/16 ID hose rather than to a screw coupling.

Here is a photo with the assembled pressure side, this is just hand tightened using plumbing PTFE tape as I don't have the NPT to BSP thread converter yet - waiting for delivery. Amazon numbers for the parts I used so far are below.

For pressure side:

Stainless strut valve no-loss coupler 1/8" NPT male
https://www.amazon.com/gp/product/B005VR4M88

Brass 1/4" NPT female to 1/8" NPT female adapter
https://www.amazon.com/gp/product/B013RWMGAY

Brass 1/4" BSP female to 1/4" NPT male converter
https://www.amazon.com/gp/product/B015ROAYWC

For vacuum side:

Stainless strut valve no-loss coupler 1/8" NPT Female
https://www.amazon.com/gp/product/B00JJND6AK

Stainless 1/8" male to 5/16" ID barb (5pk)
https://www.amazon.com/gp/product/B017N4U13Q

[BLT]

Did you manage to get the instruction plate engraved then, looks new.

[BLT]

Can anyone tell me if the neck of their tank where the cap goes has thread all the way round, like a regular jerry can, or if it's just a couple of short lengths like mine? Thanks

[iain1967s]

Did you manage to get the instruction plate engraved then, looks new.

No, I could not find anywhere to make a custom 3.75" x 9" size, so I just printed it on white card using a regular lazer printer then had it laminated in 30mil plastic at the local stationer.