My home-made hydragas pump

[mr rusty]

With Miss Rusty's Metro and it's hydragas suspension beig in need of a bit of a pump up and garages charging around £35 a go these days I thought I'd better get a pump sorted. My first attempts with a grease gun weren't too successful.......some people claim to have had success with these but I didn't, my gun was just too leaky.

However, I didn't give up and a dig around the shed turned up a forgotten bottle jack. This was put under a car, it held pressure, no leaks, so to work!!

The key to a good working pump is the proper Schrader 556 low-loss connector, aka 'strut coupler' in aeroplane speak, used for proper hydragas pumps and also gassing aircraft struts-£55 plus post from liquid levers on ebay, the robbers!!! But £38 from an aerospace supplier (LAS aerospace ltd) This is the thing- you attach it to the valve and then open the valve by turning the tap...it enables you to get the whole thing sealed up before opening the schrader valve up so there's no loss of fluid or pressure whilr you're faffing about connecting up. I adapted this to a grease gun hose by using the threaded part of a grease nipple connector and a suitable nut.



Now to make the pump- dead easy,no machining facilities required, all you need is a drill, a grinder, and a mig welder. On ye standard cheapie bottle jack there's a big nut- undo this and remove the outer cylinder- which didn't happen in my case because the nut wouldn't budge- never mind, I just literally chopped the top off the jack with the grinder, and pulled off the outer cylinder and the piston.Leave the inner cylinder in place and degrease the whole lot. I then simply drilled a hole in the side of the inner cylinder and welded on the threaded part of a grease gun connector, and welded a plate over the top of the cylinder. Connect the grease gun hose to the cylinder and you're more or less done! You see three holes i the base of the pump- these are for pressure release, overload protection, and transferring oil from the pump to the cylinder when it's a working as a jack. To test it I sank it in a bowl of water/antifreeze mix, enough to cover the holes, and connected it to the car.



Here it is connected under the car and 'on-line' so to speak.



I started pumping and woohoo it worked far better than I thought it would, the car rose visibly with each pump of the handle. So there you have it, all I need to do now is rig up some sort of remote fluid reservoir so i don't need to immerse it in fluid and it'll be complete

So up yours liquid levers and your shockingly expensive pumps!!! It's paid for itself first time out, and is a lot cheaper also than the grease-gun versions being sold on the 'bay.

[rich.]

i like that! are you near gloucester?

[mr rusty]

Afraid not! I'm in Essex, but the thing was surprisingly easy to knock up and I don't know how Liquid Levers can justify 299 notes for their basic topping-up pump,that doesn't do anything this one doesn't do. Their even more expensive ones have the vacuum facility that the old Churchill Dalek pumps have, but the general concensus among MGF folk is that you can manage without it because very few people would be starting from a completly dry system....in any case it's not something a bit of home ingenuity can't get round!

I prettied mine up a bit today by cleaning up the plate on top-it was only roughly cut out with snips and banged on with the mig, it now looks a bit tidier, not strictly neccessary though, and rounded up some bits for a remote reservoir, basically some plastic tubing and a squeezy bottle it's on the low pressure side so doesn't have to be particularly robust.

[rich.]

oh well, impressive bit of kit! i need to pump up my vdp princess 1300.. ill get it done one day..

[hillmanimpman]

very interesting i made a grease gun version a few years ago i managed to pump up the allegro but it was leaking i really needed then a new connector where did you get yours mr rusty?

[mr rusty]

This is where I got mine from- http://www.lasaero.com/site/products/ar ... =N04HO75SL. I couldn't find them any less than this, not in the UK anyway, it's a bit of a specialist item and so not that many people sell them. Or alternatively you could pay through the nose for one from liquid levers http://cgi.ebay.co.uk/HYDROLASTIC-SUSPE ... 4aa95bdb9a who I presume rely on people not knowing what they're looking for and not bothering to look elsewhere....it's amazing how much money a few minutes of web research can save!!

I found the best way to use it was to loosely couple it up first, pump some fluid through until it oozed from the connector, and then tighten it up with a spanner to seal it fully before opening the tap..this minimises the loss of system fluid before you start pumping.

[Geavsie]

I found that you can use a standard tyre Schrader adapter, with a grease gun, if you jack the car completely off the ground, with suspension fully extended. Done this with MGFs, landcrabs & wedges.