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MG MGF Technical - spheres

How do you know when you need to change the
spheres.As this is the first mgf i have
owned & the ride seems a little firm my
mgfs tyres ar standard = 215/40/16 & i have
just fitted toyos which has improved the
ride & handling no end. But still feels
a little firm. As this is the first sports
car i have owned & my other car is a merc
E class i do not have any thing to compar
it with.
STEVE MGF75LE BLACK

Rob should be along soon. Anyway I have very recently changed mine and they had going on 100,000 miles on them. That said there wasn't anything really wrong with them and were changed as a precautionary measure only.

Really most people only change them when they leak ie the hydragas fluid starts to drip out of them. This will be very obvious in two ways.

1 The car will lie low on the side that has the burst sphere.

2 There will usually be evidence of green hydragas fluid on the ground.

Don't worry too much about them, just check the ride height which should be 368mm +/- 10mm from the centre of the hub to the wheel arche liner. That is for a non lowered car.
S Laithwaite

There is no need to change, unless any is broken.

Anyway, please read how it should work
@ http://www.mgfcar.de/hydragas/hydragas.htm

Most important is the correct ride height in relation to the front and rear Toe Angles. (tracking)

The height is usual at the front 368mm +
/-10 mm at 17° C ambient temperature, cut by 0.6mm per degree below 17°.
The height can be corrected at your friendly dealer.

Anyway, check the archives and you will find loads of instructions regarding the tracking and hydragas units or displacer (spheres)

HTH
Dieter
Dieter K.

Ooops, better use the english version http://www.mgfcar.de/hydragas/ehydragas.htm

This is about a change (DIY)
http://www.mgfcar.de/defects/blownhydra.html

Dieter
Dieter K.

Car is a 2000 W reg & has only done 25000
miles & had a brand new engine fitted by
rover 2002 = HGF at 23000 miles while still
under waranty. But they still charged me
£500 for the labour. Ride height is spot
on so it might be the shocks or just me!
as i had not driven it for a while.
(SON HAD THE CAR ONLY GET TO SEE IT WHEN IT NEEDS FUEL)

THANKS.STEVE.
STEVE MGF75LE BLACK

I agree with what Stephen and Dieter have already said - hydragas spheres last the life the vehicle, and unless damaged (leaking) do not require maintenance or replacement - other than maintaining the fluid volume/pressure to keep the correct ride height.

If your car's ride height is 368mmħ10mm (measured on both front wheels, from centre of the MG logo to the wheel arch lip vertically above - as pictured here: http://www.mgf.ultimatemg.com/pump_raising_images/measuring_rideheight.JPG ), then there should be no problem with the ride - at least from a suspension perspective.

I suspect that your problem, such as it is Steve, is likely to be down to the profile of the tyres: many have commented on how much more firmly the car rides when changing from 15" wheels with 50-55% profile tyres to 16" wheels with 40% profile. I think what you are experiencing is a 'feature' - but to be sure, you ought to seek out a similarly specified car to see if yours is any different.

Hope this helps
Rob Bell

>you ought to seek out a similarly specified car to see if yours is any different.

Could be as well wrong direction mounted tyres, or anything with worn rubber bushes, worn bearings at the rear.

The car should normally have a comfortable ride and steering without any problem for normal drivers and speed up to 135 mph.
If the steering feels wobbly the anything is wrong.

Dieter K.

Went for a long drive and it felt better
the more i drove it must have been that i
had not driven it for a while as i said my
son has been driving it also forgot how
much fun they are to drive. So ive told him
to use his own car as i would rather drive
the mgf than the merc = more fun! & hes not
driving that one. I think you are right about the tyres.Thanks for all your help
STEVE.
STEVE MGF75LE BLACK

Good to hear that Steve - enjoy the driving! :o)
Rob Bell

This thread was discussed between 20/10/2003 and 22/10/2003

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