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MG MGF Technical - hydra gas system

Hi All
can i have some help please my hydra gas units have gone down so far that i cant drive the f till i get them pumped up .
so that i can drive in to town to have it done am i Abel to pump them up with just air so i can drive it the 25km
thanks Andrew
AR Cayzer

Hi Andrew,

I'd suggest not with the air as the units usually operate at around 400 psi, and also if you pump air in it will need to be fully evacuated before the fluid goes in. How far down are they? If you measure from the underside of the wheel arch to the centre of the wheel you will get the height. Mine was right down after a long period of hibernation and I drove it carefully to Brisbane (100km) with a height of only 330mm on one side and didn't encounter any problems. It depends a lot on your road conditions too - no nasty bumps or potholes is good!

Pete

Pete Cornell

All 4 wheels are rubbing i think .
i went for a drive today and on the way home i could just feel the front rubbing every now and again .
when i drove in to the garage it rubbed on the ground being so low
do you think it would be all the way down i would off thought it would have a clearance of at least a few inches

Andrew
AR Cayzer

Do you mean the car was rubbing on the ground or the wheels rubbing on the wheel arches?
Pete Cornell

You can usually drive the car gently on the bump stops without doing any damage. We drove our F about 40 kilometers in Germany when one of the rear units failed, ( letting the passenger side down flat ), without causing any other damage. Kept to 30mph and avaioded any potholes!
David Karle

wheels rubbing on the wheel arches

i thought it should be ok .
it could be a very slow trip in to town
its funny how they just went down i could see when i went out yesterday morning it was low but i have never had this happen and i have had the car 5 years i must say its well over 2 years since i have had them pumped
Andrew
AR Cayzer

Are both sides affected to the same extent, or is one side lower than the other? It sounds like they may have been slowly losing fluid over time if it's 2 years since you last had the units recharged.

Pete
Pete Cornell

yes all 4 corners are the same

the liquid must evaporate over time there is no leak its kept in the garage all the time not a drop on the cement
Andrew
AR Cayzer

Yes, it's a fairly volatile liquid and mine go down slowly with no sign of leaks or dripping on the garage floor either. I pump mine up myself with a mixture of 50% mono ethylene glycol (concentrated antifreeze) and 50% methylated spirit. I bought a suitable pump from the UK for about A$120 landed here. It might be worth looking at that option once you have it pumped up again, as you can pump it up as often as needed at almost zero cost once you have the pump.

Pete
Pete Cornell

Could be that you're not loosing fluid but loosing nitrogen from the top sphere. If the ride is getting progressively harder over the years then this is most likely the cause. They can be pumped up ( fluid ) but this does not replace the gas which is the spring of the system and only corrects the ride height. The car will be harder as a result until ultimately the gas is exhausted and you will have no spring.
JR Mailer

I pumped my F yesterday. Obviously de Nitrogen evaporates as the riding is harsh, even with the car recently pumped.
The other noticeable event is that I pumped until 39 cm of height -wheel center to rim-Why so high? Because I have learned that next day the height will be about 37cm. And that was evident today: Both front sides at 37cm, and I am sure will be lower in a few days. I wonder if we could use some different solution for pumping up the spheres, a light oil maybe.
JM Vega-P.

This thread was discussed between 14/03/2011 and 24/04/2011

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