Churchill Hydrolastic pump

[Peter Laidler]

I bet, somewhere on this forum is a bloke who has become a maestro at using, working on and mending these pumps. I wonder why he isn't offering his services to travel round and fix these wayward hydro pumps. There could be a good profit in it. Just like the bloke you phone up and comes along to fix your old power washer on-site (mines an old Warwick pump). Like IK said, most of the worn bits are the seals and gaskets etc etc and will be readily available from the specialist suppliers in imperial or the dreaded metric

[mk1]

Like IK said, most of the worn bits are the seals and gaskets etc etc and will be readily available from the specialist suppliers in imperial or the dreaded metric.

That's what I thought, but I came totally unstuck on the double seal on the pressure pump.

That's what ground me to a halt.

[111Robin]

There was a NOS service kit on eBay a while back but it went for daft money so I stopped bidding. Pressure side on mine works but the gauge is bypassed. Vacuum side hasn't worked for years. Wouldn't mind getting it fully operational again.

[Peter Laidler]

There will be a simple way around these hydro pump problems, there always is. It just needs a bit of in-depth problem solving. It's a shame Rob lives up in deepest Jockland and Mk1 lives up north somewhere, Daz lives somewhere else, so does Iain '67S. We all ought to convene somewhere. I'm sure that the illusive missing parts could be concocted using something else.......... You know the sort of thing where a not available imperial threaded part can be used by using an oversize metric threaded part can be used if you machine this and thread that and block up the secondary output thinggy..... You get my drift. I missed the perfect opportunity with my friends '.....I'm going to fix it one day' project pump that eventually went to the tip! Tosser!

[iain1967s]

After a quick inspection, the Churchill pump I recently disassembled seems at least to be complete except for the instructions plate which is missing from the top face.

Inside, apart from all the spider webs (a good sign that it's been dry stored) there is a little surface corrosion on the alloy/pot-metal parts, some furring/electrolytic corrosion at the copper to steel joints, an inch long crack in the plastic reservoir, and all of the rubber parts are all hardened of course due to many years of neglect.

I think I can fix all that... WD40 and a brass wire brush should sort out most of the corrosion issues. Not sure about what plastic the tank is made of yet - an epoxy such as Araldite/JB-Weld might work.

For the custom seals on the pump pistons that are NLA, the originals will need to be reused. Classic motorcycle restorers rejuvenate rubber parts by a week's soaking in rubbing alcohol + wintergreen oil mix (3:1 ratio). I've never tried that but it's worth a shot.

Anyway, it gives me something to tinker with in the basement during the long winter months

ps. I am in Cambridge, Massachusetts, USA (expat from Cambridge, UK)

[trevorhp]

Surely this cannot be a coincidence?
https://www.amazon.com/ACDelco-18G703-P ... B000S2PJ60

Any meeting up of the Hydro Pump Union should be in Cambridge MA but only in the summer

[Peter Laidler]

Unless you want pin-point authenticity the plastic tank should be simple fix unless it's a high pressure tank but I doubt it. There will be a local hydraulic pump that could be used as a replacement I'm sure I learned with my EPCO hydraulic jack that the fancy seals could easily be replicated by machining nylon bar and 'O' rings. As I said, the Imperial threaded bits....... Anyway, it's still working. Naturally I let wifey get under the car first of course. We've got a Cambridge here that was probably named after your Cambridge Mass. Iain.

To be honest I don't think Churchill went out of their way to complicate matters and would have used what was available off the shelf first. Just my view. Maybe we could have this Hydro Pump convention at your place............

['S'-type]

Before I realised there were so many old abandoned Churchills out there (joke), I cobbled this together for about £50. Idea nicked from the MG forum.

The joint between the flexi pipe and low loss valve is home made. I asked at Pirtek if they could make me a joint but they either couldn't or wouldn't. So it doesn't look very neat.

As you'd expect it can't evacuate the hydrolastic system but it works a treat when filling.

In reference to the use of master cylinders, I remember taking a hydro car for a pump-up at a local Mini 'experts' back in the 80s. I noticed they just used a kind of home made contraption of a mastercylinder on a base with a lever mechanism. They charged about £30. So armed with this knowledge next time I needed a re-fill I plumbed in a pipe from the master cylinder still in situ on a (scrap) Mini to the Schrader valve on another car and pumped it up that way. After that success I was planning on building my own portable set-up but never did until I discovered the version below on the MG forums.

I'm sure a Churchill is better but there's not a lot to go wrong with this simple 'fix'.

[mab01uk]

Another DIY pump solution is detailed in the link below on the Austin America website:-
Building your own hydrolastic suspension pump & service tools:
(scroll down)
http://members.tripod.com/austin_america/id63.html

[Peter Laidler]

S-type, you could have saved yourself a whole lot of money, time and effort by just buying a simple hydrolastic hand pump from Ebay. The maker has also incorporated a simple modification that I suggested to make use/life a bit easier. But really, it's not pumping fluid under pressure IN that is a problem of any sort, especially given the little pump I mentioned. It's getting the air in the system OUT or evacuating it. After all, you can compress any air remaining within the hydrolastic system and that's the last thing that you need!!!!!

You can sort-of evacuate the system by adapting a powerful vacuum cleaner (it\s a vacuum don't forget...) to it, via a catch tank (for the remaining fluid) and........... anyway....., it works. Alas, I'm banned from using our Mr Henry vacuum cleaner after setting fire to the last one! But that's another sad story. What we're about is fixing the old Churchill cabinets.

I firmly believe that a major cause of problems now is the fact that the cabinets and cabinet users still in use just recycle old fluid time and time again until it needs topping up and then - again and again and so on. I am minded to suggest that each drain down, evacuation the tank should be emptied somehow, discarded, tank sloshed out clean and refilled with new fluid THEN the system refilled. More time consuming, yes. More expensive, yes. Better in practice, yes. Just my view and readily accept being told I'm talking crap and to get a life

Incidentally, that little lo-loss valve that you're using isn't necessary. If you use a standard screw-on schrader threaded end connector, just screw it onto the hydrolastic schrader valve loosely. Pump the handle to clear the air out of the line and as soon as you see the green fluid oozing out of the schrader valve connector at the valve, tighten the connector up finger tight. This shows that the fluid feed line if free of air and you can pump away until your hearts content and the car is at the right height

['S'-type]

Now you tell me Peter!

As you can tell, I'm no engineer. More of a backstreet tin basher

Oh well it was fun mucking around with it and rest assured, no Churchills were harmed in the making of this product.

Good luck with your quest to save the Daleks from extermination!

[111Robin]

I'm surprised that the original pumps weren't fitted with a two way valve so that the old fluid could be directed into another container leaving the pump filled with only clean new fluid. However I'm sure they weren't thinking 40+ years ahead hence any cars using the pump would still have relatively fresh fluid in them anyway. I know ours has never been emptied and I certainly don't like the smell coming from the tank. Once I get the Wolsley finished I'm going to have a go at stripping the pump. I still have contacts with several seal manufacturers from work, I'm sure they could come up with something suitable.

[ChrisM]

I have a pump sitting at my place. It pumps and wees everywhere, doesn't vac. Gauges are shot. Its not mine and I have a lot on my plate at the moment. But I will check with its owner if it can be stripped. I just can't afford anything else lying around in bits at the moment. I'm in the SE and have milling , turning and grinding facilities.

Chris.

[Peter Laidler]

Depending on where you are Chris, it could be a nice winter project for someone in Oxfordshire. Unless you are a concourse freak, a gauge is depression/pressure gauge is a D/P gauge and a cheapo e-bay gauge replaced the pressure gauge I kicked off my pressure washer. In the same way a hand pump is a hand pump and so on

[Aussie Bill B]

The vacuum side on ours doesn't work either but its not a problem at all.

We pump the suspension up and then let right back down again, which pretty much evacuates all the air. Then re-pressurise and set to height.

The vacuum side of the pump isn't for removing air from the system; it's for pulling the bags up to allow for easy removal of struts, ball sockets, displacers, etc. Once you get 27 inches Hg on vacuum, the vacuum connector has to be removed from the schrader valve and air will move back into the line before it can be repressurised.

As Andrew says, air is removed by pumping up and quickly depressurising several times to remove old fluid and most of the air. Any air left in the system doesn't seem to have any effect.

I have modified my pump to catch old fluid into a soft-drink bottle and not to contaminate the main reservoir of new fluid.
The old fluid can be left standing for a few days to allow the sediment to settle. The clear fluid can be reused.

[Peter Laidler]

Not sure that I'd necessarily agree with that Aussie Bill says honourary Aussie Pete the Pom! The machine depresses/vacuums the hydro system to rid it of air. Air is the very LAST thing you need in a hydrolastic system - or it'd be called a hydro-pneumatic system surely! Of course, you can release the air into the system and remove the valves etc etc to do what you want* but when you've done everything, you've got to de-aerate/vacuum/depressurise/evacuate - call it what you want - and then pressurise it with fluid.
Or am I missing something in the explanation?

Obviously you'll never(?) completely de-aerate/evacuate the system and there'll always be a bit of air present (because the physics tells us that the fluid will contain a bit of air) but the 27Hg depression spec quoted in the EMER/manual is the figure that ensures that the HYDRO/FLUID system works at its best. That's my take on things.

I take on board the idea that if you pressurise and depressurise (D&P) the system a few times it will certainly evacuate a lot of the air from the system but believe me, no amount of this D&P will remove all of the air, certainly to the spec given. Basic physics tells us that the air will ALWAYS, always form a natural bubble at the high point. That's what air does. That point is at the inverted U bend where the front displacer hose rises up from the displacer and then down to meet the F to R hydro pipe. Now, if someone could invent a set of front hoses with a small vent-off valve at that point, life could be sooooooooo much easier. But, alas, such an invention is impossible because there ain't no room!

* in my limited experience the average Jo can do most hydro related jobs by depressurising the car so that it bottoms out. In doing so, there's no need to evacuate the system again because if you are careful and follow the simple instructions detailed earlier, no air will have entered while you carefully depressurise the system and none will enter while you pressurise it either, Eureka. A better method of re-using old fluid is to filter it through a good quality coffee filter. But........ unless you can vouch for its SG, you don't know how weak or effective the fluid is. I say always use new.

[111Robin]

Agree. Same principle when evacuating the cooling system then releasing the vacuum to draw in coolant to ensure there are no air locks. The tool I have for this purpose runs off compressed air to create the vacuum then flick the valve to draw in coolant. Never been 100% successful though.

[Aussie Bill B]

Not sure that I'd necessarily agree with that Aussie Bill says honourary Aussie Pete the Pom! The machine depresses/vacuums the hydro system to rid it of air. Air is the very LAST thing you need in a hydrolastic system - or it'd be called a hydro-pneumatic system surely! Of course, you can release the air into the system and remove the valves etc etc to do what you want* but when you've done everything, you've got to de-aerate/vacuum/depressurise/evacuate - call it what you want - and then pressurise it with fluid.
Or am I missing something in the explanation?

Obviously you'll never(?) completely de-aerate/evacuate the system and there'll always be a bit of air present (because the physics tells us that the fluid will contain a bit of air) but the 27Hg depression spec quoted in the EMER/manual is the figure that ensures that the HYDRO/FLUID system works at its best. That's my take on things.

I take on board the idea that if you pressurise and depressurise (D&P) the system a few times it will certainly evacuate a lot of the air from the system but believe me, no amount of this D&P will remove all of the air, certainly to the spec given. Basic physics tells us that the air will ALWAYS, always form a natural bubble at the high point. That's what air does. That point is at the inverted U bend where the front displacer hose rises up from the displacer and then down to meet the F to R hydro pipe. Now, if someone could invent a set of front hoses with a small vent-off valve at that point, life could be sooooooooo much easier. But, alas, such an invention is impossible because there ain't no room!

* in my limited experience the average Jo can do most hydro related jobs by depressurising the car so that it bottoms out. In doing so, there's no need to evacuate the system again because if you are careful and follow the simple instructions detailed earlier, no air will have entered while you carefully depressurise the system and none will enter while you pressurise it either, Eureka. A better method of re-using old fluid is to filter it through a good quality coffee filter. But........ unless you can vouch for its SG, you don't know how weak or effective the fluid is. I say always use new.

Hello Aussie-Pom Pete.
For the sake of the discussion...
My main point was that when the vacuum connector is removed from the valve on the car, air will pass through the schrader valve anyway, so there will be air present when repressurising.
I used to think about air in the system as you have said. But in over 30 years I've never actually had any issues likely due to air in the system. I think people get far too obsessed about it. I assume the air bubbles are compressed, like CO2 in soft drinks and appear when the pressure is released.
As you say, I suspect that if air in the system was a problem like air in the brake lines and needed to be removed, the factory would have put a bleed valve at the other end of the cars. I think it isn't needed.
1100s had their valves up on the front firewall. If that location was needed for bleeding, the minis would have had them there as well.

[Seamist Green 1100]

I have never had a problem bleeding off air out of the system without using a vacuum pump. I have proved it worked by using a vacuum pump and finding no air.
Some people just overthink hydrolastics. If you have a vacuum pump use it. If you don't have a vacuum pump just bleed it out.

[iain1967s]

Unless you want pin-point authenticity the plastic tank should be simple fix unless it's a high pressure tank but I doubt it.

The old tank is made of some kind of olefin plastic, but of course it pre-dates the introduction of material content labeling regulations so no markings to work from...

I tried four different epoxies to fix the cracks in the old tank. JB Weld Plastic Bonder seems to be the only one which will bond effectively to the original tank.

I also found a similar tank from US Plastic, part number 8819 if anyone else needs similar. It’s 5 US quarts, so around one imperial gallon. Less than the original, but unless you’re running a 1960s BMC dealership I doubt that will be a limitation.