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MG MGF Technical - Hydragas - alternatives?

Is there anyway of replacing the F’s hydragas suspension with ‘normal’ setup .. ?

My trophy’s handling is worrying me at the minute. This afternoon I accelerated hard up duel carriageway after coming off a roundabout .. quick left and right – the front of the car felt like a wheel was loose, steering was very light and the car generally felt twitchy. Even on my fav stretch of country road it just doesn’t feel right.

Each corner of the car seems to be at a different height, and the rear driver side is lowest (this was a suspected leaking sphere, but after a re-gas has been fine for 3-4 months).

From looking at the pictures from the 10th birthday – my car looks to sit a lot higher than others :(

Any thoughts, suggestions or remedies?

Cheers, Neal
N McNamara

I know you are a long way away but you seem like an ideal TechSpeed 4 nipple and setup candidate.
John Ponting

Neal, one of the things that arose from the MGF10 Q&A session was that part of the TF suspension design brief was that it should be possible to retro-fit to the MGF. Rob Oldaker and Brian Griffin explained that as Hydragas would become unavailable in future, a perfectly good car may have to be scrapped due to lack of parts. To get around this, you can fit all the TF suspension to the F (albeit with a bit of fettling with regard to the upper damper mounts, etc).

So if you wanted a more conventional suspension, this would be one, expensive, option to look at.

What I would suggest for your car is to check all the basics.
1. What tyres have you got fitted?
2. What are the tyre pressures?
3. Are the tyres wearing more evenly?
4. Check the chassis alignments - toe angles, ride height, camber etc
5. Is there wear in the track rod ends?
Rob Bell

Agree with Rob
What you ahve is more related to condition of bushings, tyre pressures etc than hydragas. hydragas is basically a spring. Put a coil spring in with stuffed bushings or wrong tyre pressures or bad alignment and you get the same vague results
Paul Walbran

Thanks guys...

Tyres seem fine, they are G'year F1's with plenty of even tread, pressure is a little down.

As I couldn't do the retro fit myself, I reckon that's out the window already - too pricey!

Is there an easy way to check the wear in the track rod ends - car on jack - check for any lateral movement in the wheel?

on this mornings (nursery)school-run the i noticed that the front mud flaps weren't scrapping on the speed-bumps (more like mountains IMO) as they normally do and that the passenger side of the car is raised up a good 'three-fingers' worth higher than the drivers side.... this is probably the sign of needing to be re-gassed - but I must have slow leak somewhere.

With the vague steering at speed - I'm right in saying the Trophies have speed-sensitive power steering ... wouldn't be anything to do with that?





N McNamara

The Trophy's do have the speed sensitive set up but this is controlled by the EPAS which IMO would have nothing at all to do with it.

If you have a Trophy (If I'm reading into this correctly, you have.) then it sounds to me like you are riding way way too high!

When mine comes back from it's service MGR always reset my hydragas to the standard height and the first thing I do is have it lowered back down to Trophy spec as the car feels too "bouncy" that high up.

Currently, it is only possible for me to fit one finger between my arches and the tyre. I am also running Goodyear F1's.
Kris Ford

Neal, time to get out with that measuring tape! :o)
Rob Bell


Can't find the measuring tape at the minute ... so using the fat finger measuring guide:

Driver side:
front 3 fingers
rear 1 finger

Passenger side:
front 4+ fingers
rear 4 fingers

Is this something I'm goingt o have to get the dealer to set right?

I did have a problem from the beginning with this car were the rear drivers side 'sunk' leading the dealer to think I had a leaking sphere - but I've never seen any discharge and after they re-gassed it everything has been fine for the past few months.

Thanks again, Neal
N McNamara

Both sides should be the same and the drivers side is the one to aim for if you don't have a tape measure. It is a simple job to release some fluid from the passenger side just to even up the suspension. This alone would transform the handling.
Andrew Regens

BLO@DY HELLS BELLS!!! :-)

I think you must have the very first Trophy 4X4!
(Sorry, couldn't resist)

The hydragas lines run front to back, so theoretically (spelling??) the passenger rear should be the same height as the passenger front and likewise for the drivers side. Confusing!

Not necessarilly (spelling again?) a dealer issue, more along the lines of a mechanic you trust who has access to a pump as it may be time consuming for them to drain/pump the lines and get all 4 corners equal.
Kris Ford

HAHAHA LMAO .. actually - the rear passenger side is the same height wheel - arch as my Jeep!!!

Just found a local speciallist - i'll get him to have a look!

There must be something wrong - each wheel being different :(
N McNamara

Rob,

Missed the suspension Q&A at MGF10 and would appreciate a bit more info on your comment >>Rob Oldaker and Brian Griffin explained that as Hydragas would become unavailable in future, a perfectly good car may have to be scrapped due to lack of parts<< - this sort of comment dosn't help my MGF induced paranoia one bit :)

Steve_P

Hi,

<.. i noticed that the front mud flaps weren't scrapping on the speed-bumps (more like mountains IMO) as they normally do and that the passenger side of the car is raised up a good 'three-fingers' worth higher than the drivers side.... this is probably the sign of needing to be re-gassed - but I must have slow leak somewhere ..>

Hmmm, here's me thinking for the last seven years that any loss of fluid or pressure will lower the car....

<.. the passenger rear should be the same height as the passenger front ..>

No, the hydrogas spheres might sit at the same level, but the relative height of the subframes, the suspension geometry, and above all the fact that you're measuring to the bodywork, not to a fixed reference point, makes the front and rear measurements different.

I'm in agreement with the others. Sort the suspension/tyres etc out and the car will handle fine.

Regards, Kes.
Kes



<Hmmm, here's me thinking for the last seven years that any loss of fluid or pressure will lower the car....>

Not sure of the 'tone' of that comment, I'm sure Kes your not trying to be condescending. I'm the first to admit I'm limited mechanically, but was led to believe that if one of the spheres lost fluid or pressure it would cause that corner to sink and the others to rise.

I’ve the car booked in next week with a local specialist – I will let you know the eventual (if any) diagnosis.

Thanks for the help, Neal
N McNamara

>> this sort of comment dosn't help my MGF induced paranoia one bit :) <<

LOL

I think that they were thinking into 30 or 40 years into the future Steve. The time when people come over all nostalgic for the last truely British mass-produced sports car.

I suspect that there will always be hydragas units available for the MGF - but they will almost certainly be second hand.

However, perhaps a hydragas unit does become unavailable in those years ahead? The decision taken by MG has provided us with another option - to fit more "conventional" suspension to keep our cars on teh road.

No more, no less than that! :o)
Rob Bell

Have they also come up with an option to dump the MEMS and injection and go back to good old carbs:-) ??
Ted Newman

As you have an MPi Ted, you have a distributor, so surely it is a short step to bolting on a couple of carbs, and figuring out how to wedge in a set of points... ;o)
Rob Bell

I know of severl people with twin webers on k-series cars and some type of elec-trick ignition.

I also know someone who has retrofitted injection to a 1500 engine. He is using MegaSquirt (free as in speech)- anyone here used it?

And the speed signal comes from the gearbox and is shared with the speedo, and it prolly wont go 'light' for very long before cutting out (designed like that).
Will Munns

So all is not doom for when the computer trickery gives up the ghost and replacements are no longer available!

Might have to do away with some boot space to accommodate those Webers and a pair of K&N cones!
Ted Newman

I have always wondered whether it would be possible to get rid of the hydragas units and replace them for a tradicional system. I have heard of Fs that have been successfully modified, but have not seen any report neither known of any particular car. Do you people know of any case?
Alan Patton

Why would you want to get rid of the hydrogas units?

Because they may not be available.

they said that about the Citroen DS units and they appear to still be available. I have had two companies look at giving a repair/exchane replacement for the hydro units and the do not appear to see any problems given the correct volume.

Because they will be too expensive.

That was not the feed back I was given from the people I spoke to and remember now MG is in China where better a place to seek out low cost replacements (practicing my Chinese as I type( no 24 with rice just wont do). This line is open.

Because they dont work.

Oh yes they do. There are quite a few people who have had mods and changes to the units,i.e race/rally.
I now run a system that is fully controllable linked left to right and am now trying to take the experiment to a higher level. My setup has been tested at the 'Ring and by MGF CUP racer Bill Solis, who before trying he car on track was to say at the very least, doubtfull of the effect of the changes, however as they say the proof of the pudding is in the eating, when he actually put the foot down at Curborough for the video his smile said it all( see the vidoe).
One or two other bbs members have also had rides in the car and I have not heard any put downs of the hydros.

But the main and most reliable test was the transporting of Scarlet Fever's owner down the Black Forrest valey and hearing him remark ' it really holds the road'. now even Andy will admit that the left to right weight distribution on that trip was tipped to his side (gerry 11.5 stones - Andy !!!more).
There is so much more we can do to improve , type and viscosity of fluids, electronic control of balance and pressures, automatic raising and lowering of hieghts the list goes on.
Surely a coiled piece of metal bar is a throwback to the start of the horseless carraige.
So back to my question,

Why would you want to get rid of the hydrogas???
I dont.
gerry h

Nor I Gerry :o)
Rob Bell

Neal,
The hydragas units have two spheres each, one filled with fluid and connected front to back and one filled with nitrogen. A nitrogen leak will not leave any physical evidence and the only way to check is with a pump which has a vacum facility and is connected directly to the sphere (not through the filling valves in the front) - has your garage checked that? From what you describe I think you may have a leak.

Spyros
Spyros Papageorghiou

Got Ohlins on mine. Not a name everyone in the car arena is acquainted with, but they truly are second to none!
Alex T

I didn't realise Ohlins did car stuff.
I've ridden a Yamaha R1 with Ohlins forks and shock and would have to agree with Alex-easily the best for bikes.
ninja

Exactly.. I've raced bikes for years, most recently GSXR1000's. First realised Ohlins did car shocks when I got some for my old Elise, and they're just as good. Choice of models from basic after-market to fully adjustable top notch jobs. Not cheap, but I suppose you get what you pay for.
Alex T

Flippin' eck! Yes, I've heard of Ohlins - and they definitely aren't cheap, but are of unrivalled quality. If Bilsteins and Eibachs are good - Ohlin's are better by all accounts. The Renault Clio Trophy uses them...
Rob Bell


Looks like Spyros is correct - now the fun of finding a new sphere, apparently the trophy spheres are different from standard.

To add insult to injury - driving home from the garage - I got a bad puncture :( on the passenger rear and realised I had a huge chunk out of the drivers rear .. so 2 new F1s about to be fitted :(
N McNamara

This thread was discussed between 20/10/2005 and 22/10/2005

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