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MG MGF Technical - Hydragas - 368mm or 400psi. Which is best.

Hi,

I know the suspension height should be 368 from centre of wheel to arch lip - but would 400psi per side be equally sufficient.

I only ask because my local garage wants to charge me £70 to refill based on the fact it will need to stand in the garage for 4 hours. In the past I have just turned up to tyre centres, depressured and refilled to 400psi per side and driven off. This has been fine with no problems - but I'm finding it more difficult to find tyre centres that have hydragas machines nowadays.

Do any of the Northwest F'ers know of any hydragas stations in Cheshire, (my local tyre centre used to only charge £8 per side).
Derren

No, the ride height is the important thing. The workshop manual tells you to pump it up until the ride height is correct. I know you are supposed to leave it to settle, but I ran mine into a local one-man business and we did it on the spot. He operated the pump and I held the tape measure. We certainly didn't empty the system first, just topped it up. It took about 15 minutes and he charged me a tenner. It was fine and there seemed to be no detriment from not leaving it to stand. Find a little back street garage with a helpful guy inside.
Mike Howlett

The reason that you let it stand is to allow the suspension fluid to cool to ambient temperature. Once youve done that it's only a case of pumping it up, rolling tha car back and forward a bit and bouncing on the front and rear to move the fluid about.
David Clelland

Hi,

I can't afford to leave my car at a garage for four hours. Is it not possible to hook it up the the pump, de-pressurise it completely, then fill it to the correct level, (instead of waiting for the existing gas to cool/settle before a top up).
Derren

One last thing. Do both sides ultmately need the same psi in each side. The last time I had the gas pumped up using the 368mm method - when I got it home, it looked like a tank and had rissen to nearly 500mm and each side was a different height . Not sure what had happened there ???

Since then, I have stuck to the 400psi method with no problems.
Derren

Derren you could always try the mgf centre at wolverhampton
sr foster 81

The MGF Centre does seem to be my best bet - just that little bit too far away though.
Derren

Don't forget that the ride height is based on an ambient temperature of 17 degrees centigrade. For every degree above or below this you should adjust the trim height by 0.6mm.

Ralph
Ralph Gadsby

Darren,

It depends where you live in Cheshire but if you are near to the Wirral, I used to use a garage in Birkenhead that specialises in MGs - Very friendly and knowledgeable.

I ended up buying my own pump when a sphere burst and the car was left stranded on the drive, so I haven't been for a while but they charged about £30
Mark Clayton

This thread was discussed between 04/02/2008 and 08/02/2008

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