15 replies to this topic

[msgorbra]

Hi,

 

I'm about to switch from hydrolastic to rubber suspension and want to know how to depressurise when I don´t have access to a real pump.

 

regards Goran

 

 

 

 

[minidaves]

jack car in air all 4 wheels off the ground to take the pressure out the system then wear eye/full face protection and gently crack the pipe nuts, slowly lower car back on wheels and the fluid will come out. job done

[msgorbra]

Thanks a lot, when you say "crack the pipe nuts", I suppose you mean the first smaller nut after the valve?

[Spider]

I just leave them on the ground, then using a Schrader Valve Tool (or even some valve caps have them on the other end), crack the valves about 1/2 to 1 turn until the fluid stops flowing, then remove the valves altogether.

 

It will stink and it will make a bit of a mess but nothing that won't hose away.

[nicklouse]

how about this.

 

get a suitable cycle pump flex hose. you remember it screws into the old style pump and then onto the valve.

 

at least that would give you a means of directing the fluid into a container.

 

not tried it yet but it could be a plan.

[msgorbra]

Thanks for replies! The car stands without hubs so it´s in the air.

[CobraV8]

I watched a guy do this once, on the front of the rear subframe poked a screwdriver into valves and let it all out.

[Ethel]

Wear goggles and waterproofs, or use a very long scrfewdriver (like 6ft) if you go for that option!

[mini13]

Ive let it out on metro's loads of times with just a screwdriver, i'm not saying its a good idea though.

 

however, once the fluid comes out its not at pressure, much like when pressure vesels are pressure checked, they use a liquid as its incompressible so if the vesel splits the presure is gone and there is no explosion. that said you do have a spring in there on the hydrolastic....

 

another analogy, bleeding brakes, most people are happy to crack a bleed nipple with somone pressing on the peddle, the pressure behind it is similar, possibly ore in a braking system

[Ethel]

I'm not saying it's particularly dangerous, just very messy. Sticking your thumb on a running tap makes a better analogy. I learned that lesson the hard way!

[mini13]

not as bad as a metro thats been filled with Citroen LHM fluid! LOL  that was apopular mod back in the day to increase damping by the way

[Magneto]

Really? That green fluid was/is expensive!

[mini13]

Yep, Motobuild used to do it as a service at one point for the K series metro's.

[Ethel]

Hydrolastic fluid is reputedly just water with a rust inhibitor/antifreeze in it. 

[Magneto]

Yep, I heard it was just a glycol/water mix......