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MG MGF Technical - Hydragas Pressures

I have replaced a leaking rear hydragas unit on my VVC. However to get the trim levels equal the drivers side is at 480psi and the passenger side at 360psi. I have evacuated and repressurised both sides but still get the same readings.
Is this difference ok?

Thanks Ian.
I Dale

Did you re-use the washer that fits between the knuckle and the hydagas sphere you replaced? Washers of different thickness are used at each corner to equalize height at roughly the same pressure. I guess a difference of 15-25psi would be acceptable but any more would give significantly different spring rates at each site.
Spyros Papageorghiou

> 15-25psi
It is.

Beside of the missing washer idea. Are you sure you got no air to the system while re-pumping ?
Dieter K.

I made sure the washer and spring were put back. I've completely emptied and refilled the system a few times just to make sure all the air is out. I'm beginning to think the nitrogen may be lost from one of the units as the replacement wasn't brand new. Would this cause the problem?

Ian
I Dale

Sounds reasonable, unfortunately.

Looks like requirements to testing them independant.
Do you have such tool ?
http://www.mgfcar.de/hydragas/4single_3039.jpg
*diect connector pipe* with tyre valve on the right and displacer connection thread on the left.
Got this from Ebay recently. It has a 18G??? part number I can't remember.
Dieter K.

Thanks Dieter & Spyros for your help. I haven't got one of the testing tools you mention. I will probably have to try another replacement unit.
I Dale

18G.1743 is the tool number. I think it's known from the Metro.

btw. has anyone an idea how to rust protect second hand empty displacers for storage ... inside of course.
Dieter K.

How soon after pressurisation did you take the pressure readings Ian?

Pressure recordings after altering the ride height are frequently unreliable, as you probably know. Best taken after the suspension has had time to equilibrate properly, and performed at the correct temperature (17ºC).

At the end of the day, if the car handles and rides okay, and you have equal ride height from side to side, then I wouldn't worry too much about it.

However, I agree, a 100+ psi difference from side to side is far greater than I'd be happy with too... :o(
Rob Bell

Hello Rob, it looks like it is down to a faulty hydragas unit. I'm getting it swapped.

Thanks
I Dale

Bad news regarding the faulty hydragas unit, but good news that you are getting it sorted! :o)
Rob Bell

This thread was discussed between 13/07/2003 and 14/07/2003

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